Tuning the Photometric Properties of Ternary Sm3+ Complexes Involving Mixed-Ligands

This research article deals with the synthesis of ternary Sm³⁺ complexes with 6,8-dichlorochromone-3-carboxaldehyde through solution-precipitation method. The photometric properties of resultant complexes were tuned by coordinating N-donor heterocyclic ligands with Sm³⁺ ion. The emission spectra, obtained in the visible region have been studied. Under optical excitation of 370 nm, the complexes displayed characteristic Sm³⁺-centered emission peaks at?~?563, 600 and 647 nm in solution as well as in powder state. The complexes showed thermal stability up to 175 °C. The complexes delivered quantum yield as high as 7.91% and longest emission lifetime of 0.564 ms. The color coordinates of the complexes, located in deep orange (in solution) and red (in powder) spectral region, matched well with the Society of Motion Picture and Television Engineers and European Broadcasting Union. The properties of complexes have been investigated to a significant extent due to their easy synthesis and potential applications as orange-red light emitter in a wide range of photonic applications such as display devices, OLEDs, dashboards, optical systems.

     

Nanostructured microspheres of silver @ zinc oxide: an excellent impeder of bacterial growth and biofilm

Au@TiO₂ core–shell hollow nanoparticles were prepared by a simple hydrothermal method without surfactants or templates. The core–shell structure materials were characterized by transmission electron microscopy, X-ray powder diffraction, scanning electron microscopy, and specific surface area of the test (BET). The catalytic activity was tested in a stainless reactor with a fixed bed and connected with a gas chromatograph. The results show that the microstructure, crystallography, and morphology were correlated with the hydrothermal reaction time and temperature, and the properties of the solvent. The crystallinity degree of TiO₂ and the particle size increased with the reaction time and temperature. Particles with different morphologies can be obtained when using different solvents. The size of microsphere can be controlled easily by changing the amount of TiF₄. This material exhibited the complete CO conversion temperature to be about 130 °C and no deactivation was observed after 1,000 min reaction.     

Simultaneous Quantification of Three Bioactive Lignans,viz., Phyllanthin,Hypophyllanthin, and Niranthin from Phyllanthus amarus Using High-Performance Thin-Layer Chromatography

JPC – Journal of Planar Chromatography – Modern TLC - Phyllanthus amarus, a well-known drug of the Indian Systems of Medicine, possesses a wide variety of pharmacological activities...     

Synthesis of the first poly(diaminosulfide)s and an investigation of their applications as drug delivery vehicles

This paper reports the first examples of poly(diaminosulfide)s that were synthesized by the reaction of a sulfur transfer reagent and several secondary diamines. The diaminosulfide group has the general structure of R(2)N-S-NR(2) and, although it has been used in the synthesis of small molecules, it has never been utilized in the synthesis of macromolecules until this report. A series of poly(diaminosulfide)s were synthesized at elevated temperatures, and the molecular weights of the polymers were as high as 12,400 g mol(-1) with conversions for the polymerization reaction up to 99%. The rate constants for the transamination reactions that lead to the polymers were measured in several solvents to provide an understanding the reaction conditions necessary to polymerize the monomers. The degradation of diaminosulfides were studied in D(2)O, C(6)D(6), CD(3)OD, CDCl(3), and DMSO-d(6)/D(2)O to demonstrate that they were very stable in organic solvents but degraded within hours under aqueous conditions. These results clearly demonstrated that diaminosulfides are very stable in organic solvents under ambient conditions. Poly(diaminosulfide)s have sufficient stabilities to be useful for many applications. The ability of these polymers to function as drug delivery vehicles were studied by the fabrication of nanoparticles of a water-insoluble poly(diaminosulfide) with a dye. The microparticles were readily absorbed into human embryonic 293 cells and possessed no measureable toxicity towards these same cells.     

Review on augmentation in photocatalytic activity of CoFe2O4 via heterojunction formation for photocatalysis of organic pollutants in water

In previous years, cobalt ferrite has gained huge consideration in the field of semiconductor photocatalysis for waste water treatment. Cobalt ferrite and its derivatives own tunable magnetic properties which results in higher absorption capability in comparison with other photocatalyst semiconductors. In the current review, a brief overview of CoFe₂O₄ as a semiconductor photocatalyst is presented and ferromagnetic behaviour of CoFe₂O₄ is also discussed. Few drawbacks such as agglomeration, photocorrosion and recombination rate of electrons-holes are also discussed. For the enhancement of photocatalytic action of cobalt ferrite, the role of cobalt ferrite with type I, type II, direct Z-scheme, solid state Z-scheme heterojunctions, Schottky and p-n heterojunctions based on different heterostructures were also discussed. In conclusive outlook formation of cobalt ferrite based heterojunctions is best approach for the enhancement of photocatalytic performance. This is because heterojunction formation enhanced the rate of charge separation and thus reduced the electron–hole recombination. Herein, this review highlights the CoFe₂O₄ based heterojunctions for the photodegradation of noxious organic pollutants in water. Furthermore, the future expectations and challenges in exploiting CoFe₂O₄ nanocomposites for water treatment, also discussed in precise conclusion of this review.     

Iridoid glycosides-Kutkin,Picroside I,and Kutkoside from Picrorrhiza kurroa Benth inhibits the invasion and migration of MCF-7 breast cancer cells through the down regulation of matrix metalloproteinases: 1st Cancer Update

Ethnopharmacological relevanceIridoid glycosides have been associated with decreased risks of cancer, such as hepatocarcinoma. Although Picrorrhiza kurroa has shown activity against hepatocarcinogenesis, its mechanism of action is poorly understood, further the anticancer activity of iridoid glycosides present in this plant has not been tested so far.Aim of the studyHere, MCF-7 cell lines (Human breast cancer) were used to test whether P. kurroa extract (PE) and its isolated iridoid glycosides Picroside I (PS), Kutkoside (KS), and Kutkin (KT) exerts the anti-invasion activity via down-regulation of the expression of matrix metalloproteinases (MMPs). MMPs play an important role in solid tumor invasion and migration.Materials and methodsThe activity and expression of gelatinases (MMP-2 and MMP-9) and collagenases (MMP-1 and MMP-13), protein, and mRNA were detected by gelatin zymography, and RT-PCR. The migratory and invasive capacities of MCF-7 cell lines were measured by the wound scratch migration assay. The preliminary cytotoxicity testing was done by MTT assay and propidium iodide staining. Further the inhibition of inflammatory mediators was also done by quantification of nitrite inflammatory mediators.ResultsThe study showed that PE and its isolated iridoids glycosides PS, KS, and KT exhibited considerable cytotoxic potential in a dose-dependent manner. Further PE, PS, KS, and KT inhibited MCF-7 cell invasion and migration, and decreased MMP-2, 9 and MMP-1, 13 activities. Furthermore, PS, KS, and KT reduced MMPs expression at protein and mRNA levels, and suppression of the inflammatory mediators was also exhibited.ConclusionsOur results suggest that PS, KS, and KT may be the valuable anti-invasive drug candidates for cancer therapy by suppressing Collagenases and Gelatinases. PS, KS, and KT showed good results in comparison with PE. PS and KS exhibit almost comparable down regulation while KT exhibited maximum suppression of invasion, migration, and expression of MMPs.     

Molecular modeling simulations to predict compatibility of poly(vinyl alcohol) and chitosan blends: a comparison with experiments

Molecular modeling simulations are the most important tools to predict blend compatibility of polymers that are otherwise difficult to predict by experimental means. Conflicting reports have been reported on the blend compatibility of poly(vinyl alcohol), PVA, and chitosan, CS polymers. Since both the polymers are widely used in pharmaceutics as drug-loaded particulates and as separation membranes, we felt it necessary to investigate their compatibility over the practical range of compositions. In this paper, we attempt to study the compatibility of PVA and CS polymers using molecular modeling strategies to understand the interactions between CS and PVA polymers to predict their compatibility from atomistic simulations. Flory-Huggins interaction parameter, chi, was computed at 298 K to assess the blend compatibility at different ratios of the component polymers. Miscibility was observed for blends below 50% of PVA, while immiscibility was prevalent at compositions between 50 and 90% PVA. Computed results confirmed the experimental findings of dynamic mechanical thermal analysis, suggesting the validity of modeling strategies employed. Plots of Hildebrand solubility parameter and cohesive energy density calculated at 298 K supported these findings. The chi values for blends, which satisfied the criteria of miscibility of polymers computed by atomistic simulations, agreed with the solubility criteria related to order parameters calculated from mesoscopic simulations. Miscibility between PVA and CS polymers is attributed to hydrogen bond formation and to an understanding of which of the interacting groups of CS, i.e., -CH2OH or -NH2, are responsible in blend miscibility. This was further confirmed by molecular dynamics simulations of radial distribution functions for groups or atoms that are tentatively involved in interactions. These results are correlated well to obtain more realistic information about interactions involved as a function of blend composition. Computed free-energy from the mesoscopic simulation for blends reached equilibrium, particularly when the simulation was performed at higher time step, indicating stability of the blend system at certain compositions.     

Impact of extinction ratio of single arm sin LiNbO3 Mach-Zehnder modulator on the performance of 10 and 20 Gb/s NRZ optical communication system

We investigate the impact of extinction ratio of single arm sin² LiNbO₃ Mach-Zehnder (MZ) amplitude modulator on the performance of 10 and 20 Gb/s single-channel optical communication system. For different fiber lengths, the system performance has been analyzed with the increase in the extinction ratio. The effect of variation in dispersion parameter has also been illustrated. The impact of extinction ratio (ζ), dispersion parameter and length of the fiber has been further optimized with minimum bit error rate (BER) at optimal decision threshold (10⁻⁹) for 10 and 20 Gb/s bit rate. It is found that the system gives optimum performance at extinction ratio (ζ) value 20 dB. The increase in the transmission distance from 468 km for 10 Gb/s to 532 km for 20 Gb/s has been reported, and 8 dB improvement in the Q value has been observed as the value of ζ is increased from 10 to 20 dB. At 20 Gb/s, the system gives optimum performance for dispersion parameter value only up to 4 ps/nm km; however, at 10 Gb/s the system can operate for dispersion values up to 14.3 ps/nm km. Further we investigate the self-phase modulation (SPM) effect for the increase in the input power. It is observed that the SPM effect is negligible below 3 dB m input power and it increases at higher power levels.     

Synthesis and Luminescent Properties of M<Subscript>2</Subscript>V<Subscript>2</Subscript>O<Subscript>7</Subscript>: Eu (M=Sr,Ba) Nanophosphors

A solution combustion route for the synthesis of Eu³⁺-activated M₂V₂O₇ (M = Sr, Ba) and their luminescent properties have been investigated. Structure and luminescent characteristics of Sr₂V₂O₇:Eu³⁺ and Ba₂V₂O₇:Eu³⁺ nanophosphors have been studied by x-ray diffraction, scanning electron microscopy, transmission electron microscopy, fluorescence spectrometry and Fourier transform infra-red spectroscopy. The incorporation of Eu³⁺ activator in these nanoparticles has been checked by luminescence characteristics. These nanoparticles have displayed red color under a UV source which is due to characteristics transition of Eu³⁺ from ⁵D₀ → ⁷F₂ at 613 nm in both Sr₂V₂O₇:Eu³⁺ and Ba₂V₂O₇:Eu³⁺ nanophosphors. In addition, the optimal Eu³⁺ - doped contents of Sr_2(1-x)Eu_2xV₂O₇ and Ba_2(1-x)Eu_2xV₂O₇ nanophosphors for both were 4 mol%.     

Quantification of eugenol, luteolin, ursolic acid, and oleanolic acid in black (Krishna Tulasi) and green (Sri Tulasi) varieties of Ocimum sanctum Linn. using high-performance thin-layer chromatography

Ocimum sanctum (family Lamiaceae) is a reputed drug of Ayurveda, commonly known as Tulasi. In the present work, we quantified 4 marker compounds, viz., eugenol, luteolin, ursolic acid, and oleanolic acid, from the leaf of green and black varieties of O. sanctum using high-performance thin-layer chromatography (HPTLC) with densitometry. The methods were found to be precise, with relative standard deviation (RSD) values for intraday analyses in the range of 0.52 to 0.91%, 0.77 to 1.29%, 0.11 to 0.16%, and 0.34 to 0.42% and for interday analyses in the range of 0.73 to 0.96%, 1.02 to 2.08%, 0.11 to 0.12%, and 0.39 to 0.64% for different concentrations of eugenol, luteolin, ursolic acid, and oleanolic acid, respectively. Instrumental RSD values were 0.24, 0.39, 0.21, and 0.18% for eugenol, luteolin, ursolic acid, and oleanolic acid, respectively. Accuracy of the methods was checked by conducting a recovery study at 3 different levels for the 4 compounds, and the average recoveries were found to be 99.73, 99.3, 100.58, and 100.57%, respectively. Eugenol content ranged from 0.175 to 0.362% (w/w) and luteolin from 0.019 to 0.046% (w/w) in the samples analyzed. Green variety was found to contain higher amounts of ursolic acid [0.478 and 0.348% (w/w), from Sources 1 and 2, respectively] than the black variety [0.252 and 0.264% (w/w) from Sources 1 and 2, respectively]. Black variety had 0.174 and 0.218% (w/w) of oleanolic acid from Sources 1 and 2, respectively, while it was not detected in the green variety. Ursolic acid and oleanolic acid ran at the same Rf value and could not be resolved in several solvent systems tried. However, we observed that only ursolic acid gave yellow fluorescence under 366 nm ultraviolet light after derivatization with anisaldehyde-sulfuric acid reagent. The HPTLC-densitometry methods for the quantification of the 4 markers in O. sanctum leaf will have the applicability in quality control.