Temperature Dependent Raman Spectroscopic Study of the Fe Doped La0.67Sr0.33MnO3 Prepared Using Ball Milling Method

Physics of the Solid State - Polycrystalline samples of La0.67Sr0.33Mn0.65Fe0.35O3 (LSMFO) were synthesized using the standard ball mill method with different calcination temperatures ranging from...     

Ultrasound-aided rapid and enhanced adsorption of anionic dyes from binary dye matrix onto novel hematite/polyaniline nanocomposite: Response surface methodology optimization

In recent times, polyaniline (PANI), a conducting polymer, has been studied widely for environmental remediation application due to its controllable electric conductivity with high surface area, which makes it a suitable adsorbent material. But lower mechanical stability of PANI is considered to be a serious drawback for its large-scale industrial application. To improve the mechanical strength of PANI, in this study, hematite nanoparticles were impregnated onto PANI by oxidative polymerization method in order to fabricate a novel organometallic nanocomposite (hematite-PANI-NC). The hematite-PANI-NC was used as adsorbent for removal of methyl orange (MO) and eosin yellow (EY) dye from binary dye matrix under ultrasonic-assisted adsorption. Excellent MO and EY dye removal (more than 98%) was observed from binary matrix at a wide solution pH from 2.0 to 6.0, and under ultrasound wave the adsorption equilibrium was achieved within 15 min only. Both MO and EY dyes adsorption experimental data strictly followed Langmuir isotherm, and maximum monolayer adsorption capacity of 126.58 mg/g and 112.36 mg/g was observed for MO and EY dye, respectively. The uptake mechanism of MO and EY dyes onto hematite-PANI-NC is governed by electrostatic interaction, π-π bonding and hydrogen bonding between dye molecules and nanocomposite. Response surface methodology analysis reveals maximum MO and EY removal of 98.43% and 99.35% at optimum experimental conditions. This study implies that the hybrid organometallic material hematite-PANI-NC has high potential for quick and enhanced sono-assisted uptake of anionic dyes from water near neutral solution pH.     

Effect of Chain Length of Polyethylene Glycol and Crosslink Density (NCO/OH) on Properties of Castor Oil Based Polyurethane Elastomers

The equilibrium swelling study of polyurethanes (PU) was carried out in various solvents in order to calculate their solubility parameter. The kinetics of swelling and sorption have also been studied in 1,4‐dioxane at 30°C. The PU was synthesized by reacting a novel polyol (castor oil derivative and epoxy based resin, EpxR) and one of the polyethylene glycols (PEG 200, PEG 400, PEG 600) with different weight compositions, with a toluene diisocyanate (TDI) adduct (derived from toluene diisocyanate and R60 polyol). Different NCO/OH ratio viz. 1, 1.3 and 1.7 were employed in the study. The results were found to vary with the weight composition of polyol components, as well as the crosslink density of the samples. The sorption behavior is also found to vary with the molecular weight of polyethylene glycol employed in the preparations of the polyurethanes. Kinetic studies of swelling revealed that the sorption is anomalous in nature. The diffusion coefficient (D) increased with an increase in the NCO/OH ratio and decreased with an increase in chain length of polyethylene glycol. The sorption coefficient (S) decreased with an increase in crosslink density (NCO/OH) and increased with increasing polyethylene glycol (i.e., PEG 200, PEG 400, and PEG 600) moieties in the polyurethanes. The molecular weight between two crosslink points was calculated using the Flory Rehner equation (24), and hence, the number of chains per unit volume (N) and degree of crosslinking (ν) in all the samples were determined.     

Allylic Hydroxylation Through Acid Catalysed Epoxy Ring Opening of Betulinic Acid Derivatives

Acid catalysed epoxy ring opening of several lupane type triterpenoids leads to unusual allylic hydroxylation. The reaction involves the formation of epoxide by m‐chloroperbenzoic acid followed by the treatment of mineral acid. The simple methodology finds utility to introduce a hydroxyl function at the allylic position in these triterpenoids, which is otherwise quite difficult.     

An Efficient Method for Agrobacterium-Mediated Genetic Transformation and Plant Regeneration in Cumin (Cuminum cyminum L.)

Cumin is an annual herbaceous medicinally important plant having diverse applications. An efficient and reproducible method of Agrobacterium-mediated genetic transformation was herein established for the first time. A direct regeneration method without callus induction was optimised using embryos as explant material in Gamborg’s B5 medium supplemented with 0.5-μM 6-benzyladenine and 2.0-μM α-naphthalene acetic acid. About 1,020 embryos (a mean of 255 embryos per batch) were used for the optimisation of transformation conditions. These conditions were an Agrobacterium cell suspension of 0.6 OD₆₀₀, a co-cultivation time of 72 h, 300-μM acetosyringone and wounding of explants using a razor blade. Pre-cultured elongated embryos were treated using optimised conditions. About 720 embryos (a mean of 180 embryos per batch) were used for transformation and 95 % embryos showed transient β-glucuronidase expression after co-cultivation. Putative transformed embryos were cultured on B5 medium for shoot proliferation and 21 regenerated plants were obtained after selection and allowed to root. T₀ plantlets showed β-glucuronidase expression and gene integration was confirmed via PCR amplification of 0.96 and 1.28 kb fragments of the hygromycin-phosphotransferase II and β-glucuronidase genes, respectively. In this study, a transformation efficiency of 1.5 % was demonstrated and a total of 11 transgenic plants were obtained at the hardening stage, however, only four plants acclimatised during hardening. Gene copy number was analysed by Southern blot analysis of hardened plants and single-copy gene integration was observed. This is the first successful attempt of Agrobacterium-mediated genetic transformation of cumin.     

Stereoselective tandem synthesis of oxazolo-fused pyrroloquinolines from o-alkynylaldehydes via Ag(I)-catalyzed regioselective 5-exo-dig ring closure

A tandem approach for the regio- and stereoselective synthesis of oxazolo-fused pyrroloquinolines 3a–l via the reaction of o-alkynylaldehydes 1a–i with chiral amino alcohols 2a–c under mild reaction conditions is described. The possible participation of the pyridine ring in the regioselective formation of 5-exo-dig cyclized products was supported by the controlled experiments. The structures and stereochemistry of the products were confirmed by NOESY and X-ray crystallographic studies.     

Selective fluorescence and naked eye detection of histidine in aqueous medium via hydrogen bonding assisted Schiff base condensation

Visible light excitable rhodamine B derivative (TARDHD) has been developed for fluorescence and naked eye detection of histidine in aqueous medium. TARDHD shows 45 fold fluorescence enhancement in the presence of histidine. It forms Schiff base with histidine and stabilizes via intra-molecular H-bonding. TARDHD can efficiently detect intracellular histidine.     

Assessment of inhalation exposure potential of broken uranium ore piles in low-grade uranium mine

This paper presents the assessment of inhalation exposure potential of broken uranium ore piles in different stopes of Jaduguda uranium mines of India. ²²²Rn emanation coefficient of broken uranium ore was measured in laboratory by collecting air sample from airtight glass jar containing ore sample. An attempt was also made to correlate the emanation coefficient with ²²⁶Ra content of the ore. The ²²²Rn progeny doses estimated based on radon activity concentration of broken ore, occupancy period and equilibrium ratio in different stopes were well below the prescribed limit of International Commission on Radiological Protection. The maximum ²²²Rn progeny dose contribution from broken ore piles was worked out to be 0.22 mSv year^?1. This suggests that the broken ore piles are not the significant contributor of inhalation exposure under the existing ventilation condition of Jaduguda uranium mine.     

Molecular structural investigations of quinoxaline derivatives through 3D-QSAR,molecular docking,ADME prediction and pharmacophore modeling studies for the search of novel antimalarial agent

In the present article, a dataset of 63 quinoxaline derivatives were taken for antimalarial activity and pharmacophore were developed. Atom based method was used to develop a three dimensional quantitative structure activity relationship (3D-QSAR) model. On comparison of all statistical parameters, model AHRRR23 was found to be the most effective and predictive QSAR model as it satisfied all statistical parameters of a good model. The model AHRRR23 showed an adequate R² value for the training set 0.9446, good predictive power with Q² of 0.6409, good F- value, low SD 0.1218 value and outstanding Pearson-R values and low RMSE 0.2779 values of the model. The docking studies also gives very good results with good RMSD values. 3D QSAR, docking and ADME studies exhibits that the developed model could be employed as a potential lead for further study as antimalarial drug.