Synthesis of indole based novel small molecules and their in vitro anti-proliferative effects on various cancer cell lines

Indole based novel small molecules were designed as potential anticancer agents. Multi step synthesis of these compounds was carried out by using Pd/C–Cu mediated coupling–cyclization strategy as a key step. The single crystal X-ray diffraction study was used to confirm the molecular structure of a representative compound unambiguously. Many of these compounds were evaluated for their anti-proliferative properties in vitro against six cancer cell lines as well as noncancerous cells. All these compounds showed selective growth inhibition of cancer cells and several of them were found to be promising with IC₅₀ values in the range of 0.1–1.2 μM, comparable to the known anticancer drug doxorubicin.     

Self-energy analysis of multiple-bosonic mode coupling in Sr2RuO4

We report angle-resolved photoemission spectroscopy studies on Sr₂RuO₄. We observe multiple-bosonic mode coupling in the α and β band dispersions. To extract the self-energy from the data for which the usual fitting methods do not work well, we propose a scheme that exploits the relation between the spectral intensity and self-energy, termed as relative self-energy. The relative self-energy obtained in that way contains important features of the self-energy. We observe not only the features that can be obtained from the band dispersions but also additional features that were not seen.     

Reabsorption in a neodymium fibre laser

Resonance absorption, the reabsorption of laser light by the laser transition of the dopant material itself, is found to be the limiting factor for fibre lasers when extremely long fibres are used. We report on measurements of the temperature dependence of the losses in a 8.5 m long commercial Nd³⁺ doped fibre (York, ND 95020/E). To determine the reabsorption losses, the threshold power has been measured as a function of temperature between 243 K and 413 K. The results are compared with theory assuming a ⁴l level energy of 2110 cm^-1 and an absorption cross-section of δ = 1.15 x 10^-20cm². The comparison shows that reabsorption from the thermally populated ⁴l level is the dominant contribution to the measured losses.     

Radiative strength functions in odd-A spherical nuclei

The radiative strength functions for the partial γ-transitions from neutron resonances to the ground and low-lying states of odd-A spherical nuclei are calculated within the quasiparticle-phonon nuclear model. The fragmentation of one-quasiparticle and quasiparticle-plus-phonon states is calculated. This allowed one to calculate γ-transitions between the one-quasi-particle components (valence transitions) and γ-transitions between the quasiparticle-plus-phonon and one-quasiparticle components of the wave functions. The energy dependence of the strength functions $\text{C}$(E1, η) and $\text{C}$(M1, η) is calculated near the neutron binding energy B_n for ⁵⁵Fe and ^{59, 61}Ni. The corresponding experimental data are described qualitatively. The contribution of the valence E1 transitions to the strength function is shown to be from 20% to 90%, and M1 transitions about 1%. The influence of the M1 giant resonance is important for M1 transition probabilities.     

Development of a liposome-based immunochromatographic strip assay for the detection of Salmonella

Salmonella species are ubiquitous human pathogens which pose a dangerous threat to the elderly and children worldwide. In this study, to develop a more efficient assay procedure for the rapid detection of Salmonella Typhimurium, an immunochromatographic strip assay was developed using immunoliposome (anti-Salmonella IgG-tagged) encapsulated with sulforhodamine B (SRB). The detection sensitivity of the developed immunochromatographic assay was compared with a commercial immunochromatographic test strip using colloidal gold nanoparticles. The liposomes were prepared through a reverse-phase evaporation method by using a lipid and phospholipid mixture and SRB, a fluorescence dye, which was encapsulated in the phospholipid bilayer. Furthermore, the outer surface of the SRB-encapsulated liposome was conjugated with antibody (affinity-purified polyclonal goat anti-Salmonella IgG) to form an immunoliposome (size, 223 nm), used as the analytical reagent in the developed immunoassay. For this strip assay, a plastic-backed nitrocellulose strip was immobilized with two antibody zones. The lower zone of the strip referred to Salmonella antigen capture zone (test line), while the other zone served as a positive control (control line). The lower zone was coated with affinity-purified polyclonal goat anti-Salmonella IgG, while the upper zone was coated with rabbit anti-goat IgG. During capillary migration of the wicking solution (diluted liposome and Salmonella culture, each 50 μl), Salmonella was captured with surface-bound immunoliposomes at the antigen capture zone, while the unbound liposomes migrated upward and bound to another zone. The color density of the antigen capture zone was directly proportional to the amount of S. Typhimurium in the test sample. As a result, the detection limit of the immunochromatographic strip assay developed in this study against S. Typhimurium was found to be 10² CFU/ml, which was significantly higher than the detection limit (10⁷ CFU/ml) of the commercial immunochromatographic test strip assay.     

Bioinspired Si subwavelength gratings by closely-packed silica nanospheres as etch masks for efficient antireflective surface

We experimentally investigate the antireflective properties of various silicon (Si) subwavelength grating (SWG) structures using closely-packed silica nanospheres monolayers with different sizes as etch masks and a subsequent inductively coupled plasma (ICP) etching, together with theoretical calculations based on a rigorous coupled wave analysis method. The geometric structure of Si SWGs is optimized by changing the size of nanospheres and ICP etching parameters. The antireflective properties depend strongly on the period, height, and shape of the hexagonally ordered SWG structures, especially correlated with ICP etching parameters. For an optimized Si SWG structure with a rounded cone shape, the reflectance is significantly reduced, indicating a low reflectance of <4.4% over a wide wavelength region of 300–1100 nm. From theoretical analysis, the reflectance of rounded cone-shaped Si SWG structures is minimized with a period of ∼300–350 nm and heights of >750 nm, which is reasonably consistent with the experimental results. The angle-dependent antireflection characteristics are also discussed.     

Photoluminescence studies of ZnO thin films on R-plane sapphire substrates grown by sol–gel method

Zinc oxide (ZnO) thin films on R-plane sapphire substrates were grown by the sol–gel spin-coating method. The optical properties of the ZnO thin films were investigated using photoluminescence. In the UV range, the asymmetric near-band-edge emission was observed at 300 K, which consisted of two emissions at 3.338 and 3.279 eV. Eight peaks at 3.418, 3.402, 3.360, 3.288, 3.216, 3.145, 3.074, and 3.004 eV, which respectively correspond to the free exciton (FX), bound exciton, transverse optical (TO) phonon replica of FX recombination, and first-order longitudinal optical phonon replica of FX and the TO (1LO+TO), 2LO+TO, 3LO+TO, 4LO+TO, and 5LO+TO, were obtained at 12 K. From the temperature-dependent PL, it was found that the emission peaks at 3.338 and 3.279 eV corresponded to the FX and TO, respectively. The activation energy of the FX and TO emission peaks was found to be about 39.3 and 28.9 meV, respectively. The values of the fitting parameters of Varshni's empirical equation were α=4×10^?3 eV/K and β=4.9×10³ K, and the S factor of the ZnO thin films was 0.658. With increasing temperature, the exciton radiative lifetime of the FX and TO emissions increased. The temperature-dependent variation of the exciton radiative lifetime for the TO emission was slightly higher than that for the FX emission.     

A maximum product criterion as a Tikhonov parameter choice rule for Kirsch’s factorization method

Kirsch’s factorization method is a fast inversion technique for visualizing the profile of a scatterer from measurements of the far-field pattern. We present a Tikhonov parameter choice approach based on a maximum product criterion (MPC) which provides a regularization parameter located in the concave part of the L-curve on a log–log scale. The performance of the method is evaluated by comparing our reconstructions with those obtained via the L-curve, Morozov’s discrepancy principle and the SVD-tail. Numerical results that illustrate the effectiveness of the MPC in reconstruction problems involving both simulated and real data are reported and analyzed.     

Study of alternating current conduction mechanism in polypyrrole-magnesium ferrite hybrid nanocomposite through correlated barrier hopping model

In the present work, both polypyrrole (PPy) and optimized polypyrrole–magnesium ferrite (PPy-MgFe₂O₄) hybrid nanocomposite were synthesized separately by simple oxidative chemical polymerization method and then structurally characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. The FTIR spectrum of the composite showed the presence of characteristic absorption bands of both PPy and MgFe₂O₄ in the composite confirming interfacial interaction of PPy with MgFe₂O₄. That this interaction is not affected by crystalline behaviour of predominant MgFe₂O₄ particles but that MgFe₂O₄ has embedded in PPy matrix was confirmed by XRD studies. Agglomerated granular spherical morphology of the composite was confirmed by SEM studies. Decrease in AC conductivity of the composite as compared to PPy due to the formation of interfacial heterojunction barrier between p-type PPy and n-type MgFe₂O₄ was confirmed experimentally and well supported theoretically by calculating binding energy, hopping distance and density of states at Fermi level of PPy and the composite as per CBH model.