Showing papers by "Ranjan K. Singh published in 2017"

Curcumin Quantum Dots Mediated Degradation of Bacterial Biofilms.

Abstract: Bacterial biofilm has been reported to be associated with more than 80 percent of bacterial infections. Curcumin, a hydrophobic polyphenol compound, has anti-quorum sensing activity apart from having anti-microbial action. However, its use is limited by its poor aqueous solubility and rapid degradation. In this study, we attempted to prepare quantum dots of the drug curcumin in order to achieve enhanced solubility and stability and investigated for its antimicrobial and antibiofilm activity. We utilized a newer two-step bottom up wet milling approach to prepare Curcumin Quantum Dots (CurQDs) using acetone as a primary solvent. Minimum inhibitory concentration against select gram-positive and gram-negative bacteria was performed. The antibiofilm assay was performed at first using 96-well tissue culture plate and subsequently validated by Confocal Laser Scanning Microscopy. Further, biofilm matrix protein was isolated using formaldehyde sludge and TCA/Acetone precipitation method. Protein extracted was incubated with varying concentration of Curcumin quantum dots for 4 hrs and was subjected to SDS-PAGE. Molecular docking study was performed to observe interaction between curcumin and phenol soluble modulins as well as curli proteins. The biophysical evidences obtained from TEM, SEM, UV-VIS, fluorescence, Raman spectroscopy and zeta potential analysis confirmed the formation of curcumin quantum dots with increased stability and solubility. The MICs of curcumin quantum dots, as observed against both select gram positive and negative bacterial isolates, was observed to be significantly lower than native curcumin particles. On TCP assay, Curcumin observed to be having antibiofilm as well as biofilm degrading activity. Results of SDS-PAGE and molecular docking have shown interaction between biofilm matrix proteins and curcumin. The results indicate that aqueous solubility and stability of Curcumin can be achieved by preparing its quantum dots. The study also demonstrates that by sizing down the particle size has not only enhanced its antimicrobial properties but it has also shown its antibiofilm activities. Further, study is needed to elucidate the exact nature of interaction between curcumin and biofilm matrix proteins.

Investigation of liquid crystalline property of a new calamitic liquid crystalline system methyl 4-(4ʹ-(4ʹʹ-(decyloxy)benzyloxy) benzylideneamino)benzoate

Abstract: A new polar calamitic liquid crystal, methyl 4-(4ʹ-(4ʺ-(decyloxy)benzyloxy) benzylideneamino)benzoate (M3BA) containing ether and Schiff base groups as linker with terminal polar ester group, has been synthesised and mesomorphic properties are studied by differential scanning calorimetry, polarising optical microscopy, density functional theory, temperature-dependent X-ray diffraction and temperature-dependent micro- Raman study. The smectic A (SmA) mesophase with focal conic texture has been observed with wide mesomorphic range. Layer thickness in SmA phase is greater than the optimised length of the molecule, indicating partially bilayer SmA phase. Analysis of Raman marker bands of C–H in-plane bending of phenyl rings, C=C stretching of rings, C=N stretching and C=O stretching shows structural changes at molecular level at Cr → SmA phase transition and provides proper intermolecular interactions responsible for dimeric unit in partially bilayer SmA phase.

Integrated Effect of Rhizobium and Azotobacter Cultures on theLeguminous Crop Black Gram (Vigna mungo)

Abstract: A pot experiment was performed to evaluate the integrated effect of Rhizobium and Azotobacter sp. on the plant growth, nodule appearance, no of leaf, shoot length, root length, chlorophyll contents and carbohydrate content in black gram during 2016 growing period at the Department of Microbiology, Dr. Ram Manohar Lohia Avadh University Faizabad, UP, India. Different treatments viz., T1: Control (Sterile soil+Seeds without culture treatment), T2: Sterile Soil and Seeds both are treated with Azotobacter sp., T3: Sterile Soil and Seeds both are treated with Rhizobium sp., T4: Sterile Soil and Seeds both are treated with mixed culture of Azotobacter sp. and Rhizobium sp., T5: Sterile Soil+Seeds treated with Azotobacter sp., T6: Sterile Soil + Seeds treated with Rhizobium sp., T7: Sterile Soil+Seeds treated with mixed culture of Azotobacter sp. and Rhizobium sp. All experiments were carried out in triplicate set. The T4 treatment showed maximum shoot length (51.6 cm), root length (17.3 cm), fresh and dry shoot biomass (12.99 and 3.21 g), fresh and dry root biomass (3.54 and 0.99 g), no. of leafs (20.4), root nodules per plant (18.2) and chlorophyll content (1.3 mg/g) and reducing (867.4 μg/g) and non-reducing sugar (1905.5 μg/g) content per plant biomass respectively. The Azotobacter and Rhizobium sp. have friendly associations and they have different physiology and habitat. Therefore, they help plant growth promotion by them own system. Therefore, such combination can be recommended for field application for sustainable agriculture. Excessive application of chemical fertilizers causes environmental and economic problems; hence the use of PGPR and Rhizobium bacteria can be acceptable due to cut contribution expenditure, increase in grain yield and environmental friendly.

Effect of neodymium doping on structural, electrical and magnetic properties of multiferroic GdMn2O5

Abstract: Neodymium doped gadolinium manganate with general composition (Nd0.1Gd0.9Mn2O5) was prepared by co-precipitation method. Microstructural and compositional analysis has been carried out by X-ray diffraction and scanning electron microscopy. The optical studies have been carried out by Raman and FTIR. The electrical properties studied include dielectric constant, dielectric loss, ac conductivity and activation energy in the temperature range 20–400 °C. The shift in the dielectric peak towards higher temperature side with increasing frequency indicates frequency dispersion and suggesting the relaxational behaviour of the material. Frequency dependence of ac conductivity obeys the universal power law. The value of activation energy depends on increase in frequency. The room temperature magnetic behaviour has been analyzed from the magnetic field dependent magnetization curve. The grown material exhibits the paramagnetic behavior at room temperature.

Structural and Magnetic Studies of Thermally Treated NiFe 2 O 4 Nanoparticles

Abstract: The heat treatment of nanoparticles can have a direct effect on their particle sizes, which, in turn, can influence many of their structural and magnetic properties. Here, we report the effect of sintering temperature on the chemically synthesized high-quality NiFe2O4 nanoparticles. The structural studies show the formation of pure NiFe2O4 nanoparticles with the space group $$ Fd{\bar{\text{3}}}m $$ . The inverse spinel structure was also confirmed from the lattice vibrations analyzed from Raman and Fourier transform infrared spectroscopy (FTIR) spectra. The presence of strong exchange interactions was detected from the temperature-dependent magnetization study. Moreover, at higher sintering temperatures, the grain growth due to fusion of several smaller particles by coalescing their surfaces enhances the crystallinity and its magnetocrystalline anisotropy. Coercivity and saturation magnetization were found to depend significantly on the sintering temperature, which was understood in the realm of the formation of single-domain-like structure and change in magnetocrystalline anisotropy at higher sintering temperatures.