This paper is dedicated to the numerical simulation of the flow of a liquid over a textured surface. Two cases are considered: the Cassie-Baxter wetting regime, where air is trapped in the cavities (diphasic flow), and the Wenzel wetting regime, where the cavities are filled with fluid (monophasic flow). The simulation results show that the flow over a textured surface is equivalent to a slip flow over a smooth surface. The amount of slip increases with the size of the cavity up to a maximum value, after which it decreases. The Cassie-Baxter wetting regime leads to twice as much slip as in the Wenzel regime. However, an increase in liquid pressure allows the liquid to enter the cavity, leading to a significant reduction in slip. A positive net force can be generated if the surface is partially textured, with fluid pressure generation controlled by the amount of slip.
This paper examines how bank loans evolve following unexpected deposit flows. Using bank-level U.S. commercial banks' data, we show that while large banks' lending is largely unaffected, loans at small banks significantly change after deposit shocks. Furthermore, the extent of this change among small banks depends on their exposure to off-balance-sheet liquidity risk, proxied by the level of unused commitments. Small banks with higher off-balance sheet exposures tend to extend fewer new loans following positive deposit shocks, suggesting that liquidity absorbed from the failure of other banks or market disruptions might not as easily be lent again to borrowers. Overall, these findings emphasize how off-balance-sheet risks can constrain the credit supply channel, even in the presence of liquidity surpluses.
Optofluidic photonic crystal fibers (PCFs) offer strong potential for optical biosensing due to their periodic air-hole microstructure, which allows the incorporation of biological liquid samples along the fiber length in close proximity to the core. This enhances the light-analyte interaction, thereby enabling highly sensitive biomolecular detection. However, most of the optofluidic PCF-based biosensing systems remain confined to laboratory environments because of the requirement for complex optical alignment, sensitive light coupling and bulky external imaging modules, limiting their translation to portable diagnostic platforms. In this work, we present a compact optofluidic PCF fluorescence biosensing platform, smartPCF that integrates a tapered suspended core PCF (SuC PCF) with a simplified optical configuration and smartphone-based imaging and computation. The tapered SuC PCF improves measurement reliability by providing robust and easy light coupling while enhancing optical confinement and fluorescence. The smartphone camera and light emitting diode (LED) flashlight provide real-time visualization and illumination for precise optical alignment. Following the alignment, fluorescence excitation is achieved using a compact laser diode, and emission from the fiber core is collected through the same optical path in a backscattering configuration. A custom-developed mobile application enables automated image processing, fluorescence quantification, and on-device evaluation of sample concentration. The modular magnetic fiber holder and shared optical architecture enable rapid installation and removal of the PCF without realignment of the primary imaging module, supporting plug-and-play operation. As a proof-of-concept, using smartPCF, we demonstrate the detection of interleukin-4 (IL-4) protein, an inflammatory marker over a concentration range of 0.05 nM to 50 nM.
The escalating threat of antimicrobial resistance (AMR) and the environmental impact of industrial pollutants, particularly synthetic dyes, emphasize the pressing requirement for novel solutions. This study investigates the green synthesis of ZnO/Fe2O3 nanocomposites using Urtica dioica extract with the aim of achieving dual functionality as both antimicrobial agents and photocatalysts for pollutant degradation. The nanocomposites were synthesized with varying loads of Fe2O3 (5-50%) and characterized using X-ray diffraction (XRD) and diffuse reflectance spectroscopy (DRS). XRD analysis confirmed the presence of both the hexagonal wurtzite ZnO phase and the alpha-Fe2O3 hematite phase in all the composites, while DRS analysis revealed that the bandgap energy decreased progressively (from 1.89 to 1.72 eV) as the Fe2O3 content increased. The photocatalytic efficiency of the composites was evaluated by degrading methylene blue (MB), Congo Red (CR) and safranin O (SO) dyes under visible light. This demonstrated that the degradation performance depends on the composition, with the best activity being observed at 5% Fe2O3. Antioxidant activity was assessed using a DPPH center dot free radical scavenging assay. This showed that Urtica dioica extract exhibits superior radical scavenging capacity (maximum inhibition of 38%) compared to ZnO/Fe2O3 nanoparticles (maximum inhibition of 18%). The antibacterial efficacy against Pseudomonas aeruginosa was evaluated using direct confrontation and disk diffusion methods. This revealed that the activity was dose- and light-dependent, with enhanced performance under light exposure (10 mm inhibition zone) compared to dark conditions (1 mm). This study demonstrates the successful green synthesis of biphasic ZnO/Fe2O3 nanocomposites with promising photocatalytic and antimicrobial properties. While the results suggest possible synergistic interactions between the oxides, the underlying mechanisms, including potential charge transfer effects, require further investigation using advanced characterization techniques. Using Urtica dioica extract as a biogenic source provides a promising eco-friendly approach to synthesizing nanomaterials, with potential applications in wastewater treatment and the biomedical field.
Unfilled Co4Sb12 skutterudites typically exhibit n-type conductivity at room temperature due to native donor-type defects associated with off-stoichiometric compositions arising from Sb loss during high-temperature synthesis. Achieving stable p-type conductivity in the absence of rare-earth fillers or transition-metal substitution at the Co site remains a significant challenge. Here, we report an in situ composite engineering approach in which elemental Bi (x = 0, 3, 6, 11 wt.
