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20202
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Subject: Chemistry × End date: 2020 × Start date: 2020 × Type: Thesis × Thesis Type: Ph.D ×
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    Synthesis of hybrid benzimidazoles-metal sulfide nanoformulations as antifungal agents
    (Punjab Agricultural University, Ludhiana, 2020) Radha Rani; Anjali
    Three samples of MS-NSs viz. CuS-NSs, FeS-NSs and MnS-NSs were prepared using sonochemical mediated reaction. Co-precipitation method produced three samples of MSNRs viz. CuS-NRs, FeS-NRs and MnS-NRs in solid form. Statistical analysis of antifungal potential of MS-NPs against phytopathogenic fungi of rice viz. D. oryzae, F. verticillioides, C. lunata and S. oryzae indicated that CuS-NSs exhibited the best antifungal potential. A series of 32 compounds containing benzimidazole and 1,2,4-triazole, in a single molecule, were designed using variety of spacers between the two bioactive moieties. Only four compounds viz. 1, 4, 5 and 8 were chosen for synthesis following the combined criteria of stronger binding to tubulin and lanosterol 14 -demethylase (with docking score -5.9 and - 8.9Kcal/mol, respectively), Lipinski filtrations, FMO approach and Toxtree analysis. Compound 8 (4-(1H-benzo[d]imidazol-2-yl)-2-methoxyphenyl 2-(1H-1, 2, 4-triazol-1- ylamino) acetate) was found to be the best antifungal compound against all the test fungi (ED50 16 μg/ml). U-CuS-NSs underwent in situ surface modification, via organic coating with most active benzimidazolyl-1,2,4-triazole i.e compound 8 to produce their nanohybrid (NH-CuS-8). Comparison of ED50 values led to the conclusion that hybridization of CuS-NSs with compound 8 worked well in enhancing antifungal potential of CuS-NSs against all test fungi. Priming the seeds with solutions of FeS-NSs and MnS-NSs resulted in improved seed health but CuS-NSs had negative impact. Seed treatment evaluation studies revealed great potential of NH-CuS-8 to reduce fungal infection.
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    ThesisItemOpen Access
    Evaluation of synthesized ternary doped ferrite nanoparticles and their graphene oxide composites as enzyme mimics and photocatalysts
    (Punjab Agricultural University, Ludhiana, 2020) Vibha; Manpreet Kaur
    Role of nanoferrites and their graphene Oxide (GO) composites as enzyme mimics and photocatalysts is a thrust area of research. In the present work, pure and ternary doped ferrite nanoparticles (NPs) of Mn, Co and Cu and their GO nanocomposites (NCs) were synthesized using facile sol-gel and sonication method respectively. FT-IR spectra and XRD patterns confirmed the formation of single phase ferrite NPs, GO sheets and their NC. Maximum saturation magnetization value was 65.0 emu/g for ternary ferrite NPs having formula Mn0.4Co0.4Cu0.2Fe2O4. SEM and TEM micrographs revealed the porous nature and fabrication of ferrite NPs onto GO sheets in the NCs. The larger surface area of NCs as compared to pristine NPs was confirmed by BET studies. Synthesized NPs, GO and NC were evaluated as peroxidase, superoxide dismutase (SOD) and polyphenol oxidase (PPO) enzyme mimics. MnFe2O4 NPs exhibited maximum peroxidase and PPO mimic activity, whereas SOD mumic activity was shown by CuFe2O4 NPs. Observed results were explained on the basis of structure of ferrite NPs. Synergistic adsorption and photocatalytic potential of ferrite NPs, GO and NC was studied using malachite green and methylene blue as model compounds. The adsorption data was best fitted into Langmuir adsorption isotherm and followed pseudosecond- order kinetic model. The NC exhibited better adsorption and photocatalytic activity as compared to ferrite NPs under visible light. The degradation mechanism was proposed on the basis of mass spectrometric analysis of products formed during photodegradation.