Enhanced photocatalytic degradation of levofloxacin over heterostructured C3N4/Nb2O5 system under visible light.

The growing usage of antibiotics and their subsequent release in water bodies have become a serious environmental concern. In this study, heterostructured photocatalysts C3N4/Nb2O5 have been synthesized using a simple hydrothermal method and applied to facilitate the degradation of the widely used antibiotic levofloxacin. The structural, morphological, and optical properties of the photocatalysts were characterized using XRD, SEM, TEM, UV-Vis and PL to establish the structure-property relationship. The type-II heterojunctions C3N4/Nb2O5 show remarkable activity under visible light irradiation, where Nb2O5 facilitates preferential adsorption of levofloxacin at the catalyst surface while C3N4 extends visible light absorption. This synergy resulted in superior catalytic performance (91%) in the optimized system, exceeding that of individual materials (Nb2O5 30% and C3N4 56%). The effect of catalyst dosage, pH, oxygen and point of zero is also investigated. The process is mainly photo-driven, and the trapping experiments reveal superoxide radicals as key species responsible for the degradation. Additionally, the adsorption behaviour, reformation of the degraded pollutant and reusability factors are evaluated to assess the practical feasibility of the photocatalytic system.

Cardioprotective effect of tetra(aniline) containing terpolymers through miR-15a-5p and MFN-2 regulation against hypertrophic responses.

OBJECTIVE: Cardiac hypertrophy is a condition of abnormal cardiomyocyte enlargement accompanied by ventricular wall thickening. The study aims to investigate the role of miR-15a-5p in the regulation of mitofusin-2 (MFN-2) and to explore the cardioprotective effect of terpolymers ES-37 and L-37. METHODS: In this study, the Sprague Dawley rats' cardiac hypertrophic model was established by administering 5 mg/kg Isoproterenol subcutaneously every other day for 14 days. As treatment rats received NAC (50 mg/kg), NAC treatment (50 mg/kg NAC + 5 mg/kg ISO), ES-37 (1 mg/kg) and ES-37 treatment (1 mg/kg ES-37+5 mg/kg ISO), L-37 (1 mg/kg) and L-37 treatment (1 mg/kg L-37+5 mg/kg ISO). subcutaneously every other day for 14 days. NAC, ES 37 and L-37 were given after 1 h of Isoproterenol administration in treatment groups. Cardiac hypertrophy was confirmed through morphological and histological analysis. For estimation of oxidative stress profiling, ROS and TBARS and antioxidative profiling superoxide dismutase (SOD), Catalase, and Glutathione (GSH) levels were checked. Triglyceride, cholesterol, alanine transaminase (ALT), and aspartate transaminase (AST) were performed to evaluate levels of lipid profiling and liver profiling. Molecular expression analysis was checked through real-time PCR, and western blotting both at the transcriptional and translational levels. Molecular docking studies were performed to study the interactions and modes of binding between the synthetic polymers with three proteins (Mitofusin-2, DRP-1 and PUMA). All the studies were carried out using the AutoDock Vina software and the protein-ligand complexes were visualized in Biovia Discovery Studio. Cardiac hypertrophy was confirmed by the relative changes in the cellular structure of the heart by histopathological examination and physiological changes by estimating organ weights. Biochemical profiling results depict elevated oxidative and lipid profiles signify myocardial damage. N-acetyl cysteine (NAC), ES-37, and L-37 overcome the cardiac hypertrophic responses through attenuating oxidative stress and enhancing the antioxidative signaling mechanism. miR-15a-5p was identified as hypertrophic microRNA directly regulating the expression of Mitofusin-2 (MFN-2). Significantly increased expression of miR-15a-5p, Dynamin related protein 1 (Drp1), and P53 upregulated modulator of apoptosis (PUMA), was observed in the disease group, whereas MFN-2 expression was observed downregulated. N-acetyl cysteine (NAC), ES-37, and L-37 showed increased expression of antiapoptotic maker MFN-2 and decreased expression of miR-15a-5p, Drp1, and PUMA in treatment groups suggesting their cardioprotective role in attenuation of cardiac hypertrophy. An analysis of the docking results shows that ES-37 has greater binding affinity with the target proteins compared to L-37, with the highest binding values reported for MFN-2. CONCLUSION: The physiochemical properties of ES-37 and L-37 predicted it as a good drug-like molecule and its mechanism of action is predictably through inhibition of ROS. Molecular docking results shows that the polymer ES-37 has greater binding affinity with the target proteins compared to L-37, with the highest binding values reported for MFN-2. Thus, the study validates the role and targeting of miR-15a-5p and MFN-2 in cardiac hypertrophy as well as the therapeutic potential of NAC, ES-37, and L-37 in overcoming oxidative stress and myocardial damage.

Light-Driven Catalytic Activity of Green-Synthesized SnO2/WO3-x Hetero-nanostructures.

This work reports an environmentally friendly and economically feasible green synthesis of monometallic oxides (SnO2 and WO3) and their corresponding mixed metal oxide (SnO2/WO3-x) nanostructures from the aqueous Psidium guajava leaf extract for light-driven catalytic degradation of a major industrial contaminant, methylene blue (MB). P. guajava is a rich source of polyphenols that acts as a bio-reductant as well as a capping agent in the synthesis of nanostructures. The chemical composition and redox behavior of the green extract were investigated by liquid chromatography-mass spectrometry and cyclic voltammetry, respectively. Results acquired by X-ray diffraction and Fourier transform infrared spectroscopy confirm the successful formation of crystalline monometallic oxides (SnO2 and WO3) and bimetallic SnO2/WO3-x hetero-nanostructures capped with polyphenols. The structural and morphological aspects of the synthesized nanostructures were analyzed by transmission electron microscopy and scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy. Photocatalytic activity of the synthesized monometallic and hetero-nanostructures was investigated for the degradation of MB dye under UV light irradiation. Results indicate a higher photocatalytic degradation efficiency for mixed metal oxide nanostructures (93.5%) as compared to pristine monometallic oxides SnO2 (35.7%) and WO3 (74.5%). The hetero-metal oxide nanostructures prove to be better photocatalysts with reusability up to 3 cycles without any loss in degradation efficiency or stability. The enhanced photocatalytic efficiency is attributed to a synergistic effect in the hetero-nanostructures, efficient charge transportation, extended light absorption, and increased adsorption of dye due to the enlarged specific surface area.

MoO3 Nanobelts Embedded Polypyrrole/SIS Copolymer Blends for Improved Electro-Mechanical Dual Applications.

This research endeavor aimed to develop thin film blends of polypyrrole (PPy) and poly (styrene-isoprene-styrene) (SIS) with MoO3 as a nanofiller for improved mechanical and electrical properties to widen its scope in the field of mechatronics. This study reports blends of polypyrrole (PPy) and poly (styrene-isoprene-styrene) (SIS) tri-block copolymer showing improved mechanical and electrical attributes while employing MoO3 nanobelts as nanofillers that additionally improves the abovementioned properties in the ensuing nanocomposites. The synthesis of PPy/SIS blends and MoO3/PPy/SIS nanocomposites was well corroborated with XRD, SEM, FTIR, and EDS analysis. Successful blending of PPy was yielded up to 15 w/w% PPy in SIS, as beyond this self-agglomeration of PPy was observed. The results showed a remarkable increase in the conductivity of insulating SIS copolymer from 1.5 × 10-6.1 to 0.343 Scm-1 and tensile strength up to 8.5 MPa with the 15 w/w% PPy/SIS blend. A further enhancement of the properties was recorded by embedding MoO3 nanobelts with varying concentrations of the nanofillers into 15 w/w% PPy/SIS blends. The mechanical strength of the polymeric nanocomposites was enhanced up to 11.4 MPa with an increase in conductivity up to 1.51 Scm-1 for 3 w/w% MoO3/PPy-SIS blends. The resultant product exhibited good potential for electro-mechanical dual applications.

Biferrocenyl Schiff bases as efficient corrosion inhibitors for an aluminium alloy in HCl solution: a combined experimental and theoretical study.

The corrosion inhibitive capabilities of some ferrocene-based Schiff bases on aluminium alloy AA2219-T6 in acidic medium were investigated using Tafel polarization, electrochemical impedance spectroscopy (EIS), weight loss measurement, FT-IR spectroscopy and scanning electron microscopic (SEM) techniques. The influence of molecular configuration on the corrosion inhibition behavior has been explored by quantum chemical calculation. Ferrocenyl Schiff bases 4,4'-((((ethane-1,2-diylbis(oxy))bis(4,1-phenylene))bis(methaneylylidene))bis(azaneylylidene))bisferrocene (Fcua), 4,4'-((((ethane-1,2-diylbis(oxy))bis(2-methoxy-1,4-phenylene))bis(methaneylylidene))bis(azaneylylidene))bisferrocene (Fcub) and 4,4'-((((ethane-1,2-diylbis(oxy))bis(2-ethoxy-1,4-phenylene))bis(methaneylylidene))bis(azaneylylidene))bisferrocene (Fcuc) have been synthesized and characterized by FT-IR, 1H and 13C NMR spectroscopic studies. These compounds showed a substantial corrosion inhibition against aluminium alloy in 0.1 M of HCl at 298 K. Fcub and Fcuc showed better anticorrosion efficiency as compared with Fcua due to the electron donating methoxy and ethoxy group substitutions, respectively. Polarization curves also indicated that the studied biferrocenyl Schiff bases were mixed type anticorrosive materials. The inhibition of the aluminium alloy surface by biferrocenyl Schiff bases was evidenced through scanning electron microscopy (SEM) studies. Semi-empirical quantum mechanical studies revealed a correlation between corrosion inhibition efficiency and structural functionalities.

Synthesis, characterization and biological evaluation of novel benzimidazole derivatives.

In search of achieving less toxic and more potent chemotherapeutics, three novel heterocyclic benzimidazole derivatives: 2-(1H-benzo[d]imidazol-2-yl)-4-chlorophenol (BM1), 4-chloro-2-(6-methyl-1H-benzo[d]imidazol-2-yl)phenol (BM2) and 4-chloro-2-(6-nitro-1H-benzo[d]imidazol-2-yl)phenol (BM3) with DNA-targeting properties, were synthesized and fully characterized by important physicochemical techniques. The DNA binding properties of the compounds were investigated by UV-Visible absorption titrations and thermal denaturation experiments. These molecules exhibited a good binding propensity to fish sperm DNA (FS-DNA), as evident from the high binding constants (Kb) values: 1.9 × 105, 1.39 × 105 and 1.8 × 104 M‒1 for BM1, BM2 and BM3, respectively. Thermal melting studies of DNA further validated the absorption titration results and best interaction was manifested by BM1 with ΔTm = 4.96 °C. The experimental DNA binding results were further validated theoretically by molecular docking study. It was confirmed that the molecules (BM1-BM3) bind to DNA via an intercalative and groove binding mode. The investigations showed a correlation between binding constants and energies obtained experimentally and through molecular docking, indicating a binding preference of benzimidazole derivatives with the minor groove of DNA. BM1 was the preferential candidate for DNA binding because of its flat structure, π-π interactions and less steric hindrance. To complement the DNA interaction, antimicrobial assays (antibacterial & antifungal) were performed. It was observed that compound BM2 showed promising activity against all bacterial strains (Micrococcus luteus, Staphylococcus aureus, Enterobacter aerogenes and Escherichia coli) and fungi (Aspergillus flavus, Aspergillus fumigatus and Fusarium solani), while rest of the compounds were active against selective strains. The MIC values of BM2 were found to be in the range of 12.5 ± 2.2-25 ± 1.5 µg/mL. Thus, the compound BM2 was found to be the effective DNA binding antimicrobial agent. Furthermore, the preliminary cytotoxic properties of synthesized compounds were evaluated by brine shrimps lethality assay to check their nontoxic nature towards healthy normal cells.Communicated by Ramaswamy H. Sarma.

Synthesis of new Pro-PYE ligands as co-catalysts toward Pd-catalyzed Heck-Mizoroki cross coupling reactions.

The present research work describes the synthesis of five new ligands containing pyridinium amine, [H2L1][OTf]2-[H2L5][I]2 from two new precursors, [P3 Et][I] and [P2 Me][CF3SO3]. The structure elucidations of the compounds were confirmed by multinuclear NMR (1H, 13C), FT-IR and by single crystal XRD techniques. Theoretical DFT studies were carried out to get better insight into the electronic levels and structural features of all the molecules. These synthesized new Pro-PYE ligands [H2L1][OTf]2-[H2L5][I]2 were found to be significantly active as co-catalysts for Pd(CH3CO2)2 toward Heck-Mizoroki coupling reactions with wide substrate scope in the order of [H2L1][OTf]2 ≫ [H2L2][OTf]2 > [H2L3][OTf]2 > [H2L4][OTf]2 > [H2L5][I]2.

High-performance TiO2 nanoparticle/DOPA-polymer composites.

Many natural materials are complex composites whose mechanical properties are often outstanding considering the weak constituents from which they are assembled. Nacre, made of inorganic (CaCO3 ) and organic constituents, is a textbook example because of its strength and toughness, which are related to its hierarchical structure and its well-defined organic-inorganic interface. Emulating the construction principles of nacre using simple inorganic materials and polymers is essential for understanding how chemical composition and structure determine biomaterial functions. A hard multilayered nanocomposite is assembled based on alternating layers of TiO2 nanoparticles and a 3-hydroxy-tyramine (DOPA) substituted polymer (DOPA-polymer), strongly cemented together by chelation through infiltration of the polymer into the TiO2 mesocrystal. With a Young's modulus of 17.5 ± 2.5 GPa and a hardness of 1.1 ± 0.3 GPa the resulting material exhibits high resistance against elastic as well as plastic deformation. A key feature leading to the high strength is the strong adhesion of the DOPA-polymer to the TiO2 nanoparticles.

Defect-controlled hypersound propagation in hybrid superlattices.

We employ spontaneous Brillouin light scattering spectroscopy and detailed theoretical calculations to reveal and identify elastic excitations inside the band gap of hypersonic hybrid superlattices. Surface and cavity modes, their strength and anticrossing are unambiguously documented and fully controlled by layer thickness, elasticity, and sequence design. This new soft matter based superlattice platform allows facile engineering of the density of states and opens new pathways to tunable phoxonic crystals.

Engineering the hypersonic phononic band gap of hybrid Bragg stacks.

We report on the full control of phononic band diagrams for periodic stacks of alternating layers of poly(methyl methacrylate) and porous silica combining Brillouin light scattering spectroscopy and theoretical calculations. These structures exhibit large and robust on-axis band gaps determined by the longitudinal sound velocities, densities, and spacing ratio. A facile tuning of the gap width is realized at oblique incidence utilizing the vector nature of the elastic wave propagation. Off-axis propagation involves sagittal waves in the individual layers, allowing access to shear moduli at nanoscale. The full theoretical description discerns the most important features of the hypersonic one-dimensional crystals forward to a detailed understanding, a precondition to engineer dispersion relations in such structures.