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In this study, a comparison of biofilm formation, extracellular polymeric substances (EPS) production, protein and polysaccharides estimation, and protein profiling through SDS-PAGE, FTIR, GC-MS, ESI-MS, SEM, and AFM analysis were done for EPS from epilithic bacteria Brevundimonas faecalis BC1 obtained from monumental rock under normal room temperature and heat stressed condition. Heat stress (60 ± 2 °C) that simulates hot monumental rock surfaces during the summer season caused bacteria BC1 to produce more EPS (8.56 g/L), biofilm, protein and polysaccharides, extra SDS-PAGE protein bands of different molecular weight than their control counterpart. FTIR and GC-MS analysis showed extra polysaccharide formation in the EPS under heat stress and ESI-MS analysis clearly showed differences in structural components of EPS from two different sources. Consistently, SEM and AFM showed more branching structural components with dentate spikes in the EPS obtained from a heat-stressed source than from its counterpart, suggesting their protective role toward heat stress and adhesive potential for biofilm. [ABSTRACT FROM AUTHOR]

Nowadays, miniaturization of high-performance electronic devices leads to higher heat generation, which needs efficient cooling to maintain device temperature below its operating temperature. This work proposed an efficient cooling technique using two-phase flow boiling in a recharging microchannel (RMC) and compared its performance with the conventional simple microchannel (SMC). A three-dimensional numerical investigation is carried out using the volume-of-fluid multiphase model and evaporation–condensation phase-change model in ANSYS Fluent V15. Water with mass fluxes of 100 and 500 kg/(m2·s) enters through the microchannel at inlet subcooling of 5 °C, whereas the substrate bottom surface is subjected to constant heat flux in the range of 10–40 W/cm2. The water saturation temperature is considered as 50 °C, corresponding to the saturation pressure of 12.352 kPa. Results reveal that the RMC shows enhanced heat transfer coefficient, reduced thermal resistance, reduced wall superheat, and reduced substrate temperature compared to SMC. Besides, the RMC shows a reduced pressure drop than the SMC at lower mass flux, whereas it shows an increased pressure drop at higher mass flux. The flow boiling instabilities can mitigate during the bubbly flow regime in RMC. This study suggests the possible application of flow boiling in RMC to cool high-performance electronic devices. [ABSTRACT FROM AUTHOR]

Background: Antimicrobial resistance has become a serious concern and threat to global health. This has triggered the need for the design of new antimicrobials. In this study, poly‐ionic liquid (PIL) homopolymers have been designed by varying the alkyl chain lengths to evaluate their pathogeneses against Gram‐positive (Staphylococcus aureus) and Gram‐negative bacteria (Escherichia coli). Results: The results demonstrated that the antimicrobial and antibiofilm activities depend on the alkyl chain length of PILs (C10 > C8 > C6). To support the experimental findings, in silico analyses were performed to explore the structural and functional information of bacterial RNA polymerase (RNAP) enzymes. A switch region was identified between RNAP β subunit (RpoB) and RNAP β' subunit (RpoC) with 1119 amino acids (aa) and 1504 (2–1505) aa, respectively. The docking analysis reflected the docking energies −5.313 kcal mol−1 for RNAP‐poly‐1‐vinyl‐3‐hexyl imidazolium complex, −4.634 kcal mol−1 for RNAP‐poly‐1‐vinyl‐3‐octyl imidazolium complex, and −3.456 kcal mol−1 for RNAP‐poly‐1‐vinyl‐3‐decyl imidazolium complex. Conclusion: The synthesized PIL samples exhibited antibacterial and antibiofilm activities against E. coli and S. aureus. However, the effect on E. coli was more prominent in comparison to S. aureus. The results indicated that both electrostatic interaction and hydrophobic effect played a vital role in enhancing the antibacterial as well as antibiofilm activities. In addition, in silico analysis identified the 'switch region' between RNAP β subunit (RpoB) and RNAP β subunit (RpoC). The novel target appeared to be a binding region for PILs and restricted the synthesis of bacterial RNA. It can be concluded that imidazolium‐based PILs can be used as safe antibacterial materials in the healthcare sector. © 2024 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

In recent years, bacterial infection has become one of the significant clinical challenges. The overuse or misuse of antibiotics increases the number of antibiotic‐resistant bacterial pathogens and causes enormous medical burdens with high morbidity and mortality. Several strategies have been adopted to tackle this; poly‐ionic liquids (PILs), a class of ionic liquids (ILs) systems demonstrating a broad spectrum of antimicrobial activities, have been widely used in biomedical applications. During polymerization, the charge density of the cations, molecular weight, and hydrophobic behavior can be regulated to accomplish more potent antibacterial efficacy with low cytotoxicity. However, inadequate literature is available highlighting the application of PIL‐based materials in biomedical applications. Keeping this in mind, the recent advances in PIL‐based biomaterials formed by conjugating PIL with natural and synthetic polymers as effective antimicrobial agents have been the focus area of this review. [ABSTRACT FROM AUTHOR]