University of North Bengal

Green synthesis of silver nanoparticles has been proven to be an efficient, cost-effective, and eco-friendly method in modern research. For the current work, Macropanax undulatus aqueous extract was used for synthesizing silver nanoparticle (AgNPs). The synthesized AgNPs were characterized by UV-Vis spectroscopy, Dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), X-ray powder diffraction (XRD), transmission electron microscopy (TEM), and energy-dispersive X-ray analysis (EDX). Further antioxidant, anti-inflammatory, antidiabetic, cytotoxicity, and antimicrobial activities were done to evaluate pharmacological properties. MU-AgNPs characteristic absorption peak at 442 nm (lambda max) was visible in UV-Vis spectroscopy in response to surface plasmonic resonance. Functional groups of extract and MU-AgNPs were confirmed by the FT-IR. The particle size of 124.46 nm was determined through DLS. Further spherical shape and size were confirmed by the SEM and TEM. To determine the stability of the silver nanoparticles, Zeta potential study was carried out. Crystallin nature of MU-AgNPs was confirmed by XRD. Confirmation of presence of silver was confirmed by EDX. A protein corona (PC) forms when nanoparticles come into contact with proteins upon introduction into the body. To further investigate this function, protein, and DNA binding studies were carried out. MU-AgNPs showed potent antioxidant, anti-inflammatory, antidiabetic, cytotoxicity, and antimicrobial activities. The results concluded that MU-AgNPs might be potent therapeutic agent for novel drug delivery.

An interacting Holographic dark energy (HDE) with different infra-red (IR) cutoffs (Hubble horizon and future event horizon) is investigated in the background dynamics of flat Friedmann Lemaitre Robertson Walker (FLRW) universe where gravitational particle creation effects via different form of particle creation rates (1) r = 3/3H and (2) r = 3aH0 +3/3H are considered. The created particles are considered to be pressureless Dark Matter (DM) which interacts with the HDE through a phenomenological choice of interaction term Q = 3yHPm. We obtain an analytic solution of the cosmological dynamics with Hubble horizon as IR cutoff when the creation rate is taken as r = 3/3H. On the other hand, employing the Hubble horizon and the future event as IR cutoffs for the model of HDE does not provide the analytic solution when the creation rate is taken as r = 3aH0 + 3/3H. We then analyze the model separately using the dynamical systems theory. From the analysis, the model (with Hubble horizon as IR cutoff) provides two sets of critical points. One can give a late-time accelerated universe evolving in quintessence, the cosmological constant, or the phantom era. On the other hand, by applying the future event as an IR cutoff, the model provides the complete evolution of the universe. Global dynamics of the model are investigated by defining the appropriate Lyapunov function. The squared sound speed calculated and plotted to find stability of the models.

Xylooligosaccharides (XOS) are excellent prebiotic which improve health through selective modulation of beneficial gut microbiome. Its production from agroresidues using microbial xylanase is considered as sustainable and economic approach. In this study a xylanase producing bacterium isolated from decaying wood soil was phylogenetically identified and designated as Bacillus stercoris DWS1. Xylanase (BsXln1) purified from the bacterium had pH and temperature optima of 7 and 37-60 degrees C, respectively, and it retained 85 % activity upon preincubation at 60 degrees C for 40 min. Indicating its moderate thermostability. Zymogram analysis of partially purified BsXln1 revealed its molecular weight of similar to 35 kDa. B. stercoris DWS1 produced 200 U mL(-1) of BsXln1 in presence of 1.5 % sugarcane bagasse (SCB) as carbon source; which was enhanced to 591 U mL(-1) through optimization of cultural conditions. Xylan extracted from SCB was morphologically and structurally characterized, and then depolymerized by BsXln1 to yield XOS (400 mg g(-1)). Analysis of purified XOS by TLC, followed by ESI-MS showed predominance of xylobiose and xylotriose. XOS exhibited in vitro antioxidant activities against DPPH and ABTS free radicals, however, it had limited prebiotic activity on Lactobacillus plantarum and Lactobacillus fermentum under anaerobic condition. In conclusion, the xylanase, BsXln1, produced by B. stercoris DWS1 can be used in food industries for efficient production of bioactive XOS from agroresidues.

Antibiotic resistance presents an alarming threat to global health, with bacterial infections now ranking among the leading causes of mortality. To address this escalating challenge, strategies such as antibiotic stewardship, development of antimicrobial therapies, and exploration of alternative treatment modalities are imperative. Metal-organic frameworks (MOFs), acclaimed for their outstanding biocompatibility and in vivo biodegradability, are promising avenues for the synthesis of novel antibiotic agents under mild conditions. Among these, zeolitic imidazolate frameworks (ZIFs), a remarkable subclass of MOFs, have emerged as potent antibacterial materials; the efficacy of which stems from their porous structure, metal ion content, and tunable functionalized groups. This could be further enhanced by incorporating or encapsulating metal ions, such as Cu, Fe, Ti, Ag, and others. This perspective aims to underscore the potential of ZIFs as antibacterial agents and their underlying mechanisms including the release of metal ions, generation of reactive oxygen species (ROS), disruption of bacterial cell walls, and synergistic interactions with other antibacterial agents. These attributes position ZIFs as promising candidates for advanced applications in combating bacterial infections. Furthermore, we propose a novel approach for synthesizing ZIFs and their derivatives, demonstrating exceptional antibacterial efficacy against Escherichia coli and Staphylococcus aureus. By highlighting the benefits of ZIFs and their derivatives as antibacterial agents, this perspective emphasizes their potential to address the critical challenge of antibiotic resistance.

Redox-active quinoline-containing [NiII(2PyN2Q) (H2O)]2+ complex (1) has been developed for the electrocatalytic (e) hydrogen evolution reaction (HER) in the presence of organic acids and water and for the hydrogen-atom-transfer (HAT) reaction with styrene in the presence of acids. Complex 1 shows promising e-HER performance in water up to pH 9. It exhibits a stepwise (E)ECEC mechanism with AcOH, while a potential-dependent bimolecular homolytic pathway and CEEC mechanism is operative with p-toluene sulfonic acid during the e-HER. The one- and two-electron-reduced species of 1 are characterized by spectro-electrochemistry, optical, and EPR studies. Moreover, the inverse kinetic isotope effect (KIE = 0.83) between AcOH and d4-AcOH during the e-HER and e-HAT with styrene for the hydro-functionalization reaction using catalyst 1 possibly suggests the involvement of nickel hydride species. The e-HER and e-HAT reactivity of 1 have been compared with redox-inactive redox-inactive [NiII(N4Py)(H2O)]2+ (2), demonstrating the prominent effect of quinoline in the e-HER and pyridine in the e-HAT. The proposed mechanism of the e-HER with AcOH is well supported by DFT studies.