No abstract

Reaction of salicylaldehyde-2-picolinylhydrazone (HL) Schiff base ligand with precursor compounds [{(p-cymene)RuCl2}2] 1, [{(C6H6)RuCl2}2] 2, [{Cp*RhCl2}2] 3 and [{Cp*IrCl2}2] 4 yielded the corresponding neutral mononuclear compounds 5-8, respectively. The in vitro antitumor evaluation of the compounds 1-8 against Dalton's ascites lymphoma (DL) cells by fluorescence-based apoptosis study and by their half-maximal inhibitory concentration (IC50) values revealed the high antitumor activity of compounds 3, 4, 5 and 6. Compounds 1-8 render comparatively lower apoptotic effect than that of cisplatin on model non-tumor cells, i.e., peripheral blood mononuclear cells (PBMC). The antibacterial evaluation of compounds 5-8 by agar well-diffusion method revealed that compound 6 is significantly effective against all the eight bacterial species considered with zone of inhibition up to 35 mm. Fluorescence imaging study of compounds 5-8 with plasmid circular DNA (pcDNA) and HeLa RNA demonstrated their fluorescence imaging property upon binding with nucleic acids. The docking study with some key enzymes associated with the propagation of cancer such as ribonucleotide reductase, thymidylate synthase, thymidylate phosphorylase and topoisomerase II revealed strong interactions between proteins and compounds 5-8. Conformational analysis by density functional theory (DFT) study has corroborated our experimental observation of the N, N binding mode of ligand. Compounds 5-8 exhibited a HOMO (highest occupied molecular orbital)-LUMO (lowest unoccupied molecular orbital) energy gap 2.99-3.04 eV. Half-sandwich ruthenium, rhodium and iridium compounds were obtained by treatment of metal precursors with salicylaldehyde-2-picolinylhydrazone (HL) by in situ metal-mediated deprotonation of the ligand. Compounds under investigation have shown potential antitumor, antibacterial and fluorescence imaging properties. Arene ruthenium compounds exhibited higher activity compared to that of Cp*Rh/Cp*Ir in inhibiting the cancer cells growth and pathogenic bacteria. At a concentration 100 µg/mL, the apoptosis activity of arene ruthenium compounds, 5 and 6 (~30 %) is double to that of Cp*Rh/Cp*Ir compounds, 7 and 8 (~12 %). Among the four new compounds 5-8, the benzene ruthenium compound, i.e., compound 6 is significantly effective against the pathogenic bacteria under investigation.

No abstract

PurposeThe purpose if this paper is to examine the turn-of-the-month effect in the equity market of three major emerging countries – Brazil, India and China – from January 2000 to December 2017.Design/methodology/approachOrdinary least square regression analysis is used to examine the presence of the turn-of-the-month effect and to test the efficiency of the emerging stock markets. The characteristics of the returns during the turn-of-the-month days are compared with that of the non-turn-of-the-month trading days.FindingsThe average returns during turn-of-the-month days for all the considered emerging market indices are significantly higher than the non-turn-of-the-month days for the full sample. For the subsample analysis, the average returns for Brazil and India for pre-GFC period are higher on the turn-of-the-month days than on the non-turn-of-the-month days. However, the effect disappears in China during the GFC period. During the crisis period, the results show that the turn-of-the-month effect disappears in Brazil and India, whereas for China, the effect is significant. For the post-GFC period, the-turn-of-the-month effect reappears for all the countries.Practical implicationsThe results have important implications for both traders and investors. The authors’ results indicate that the market participants can time the stock markets of these countries by taking long positions especially during the times when the turn-of-the-month effect is highly significant.Originality/valueTo the best of the authors’ knowledge, this paper is the first to study the turn-of-the-month effect, in the key emerging countries such as Brazil, China and India. Second, the authors divide the sample into three subperiods based on the 2008 GFC such as pre-GFC, GFC and post-GFC to understand the dynamic behavior of turn-of-the-month effect over time. Most importantly, the authors control for the day-of-the-week effect while examining the turn-of-the-month effect.

No abstract

No abstract

The modulated bioactivity of proteins immobilized on nanoparticle (NP) interfaces is of tremendous interest toward designing better therapeutic and diagnostic tools. In this work, binding behavior and the antibacterial activity of free lysozyme (LYS) as well as its non-covalent assembly with silver (Ag) and gold (Au) colloidal NPs were compared in presence of two model drugs, viz. sulfadiazine (SDZ) and caffeine (CAF). Intrinsic protein fluorescence was found to quench due to the formation drug-protein complex in case of CAF resulting a linear Stern-Volmer (SV) plot with K = 1.83 × 10 M.On the other hand, a positive deviation beyond [SDZ] ~0.15 mM is explained due to the formation of a fluorophore - quencher sphere with radius of 13.85 ± 1.80 Å that results almost one order of magnitude higher K (1.75 × 10 M). Molecular docking calculation also predicts relatively more stabilized complex of SDZ with LYS in comparison to CAF (ΔE ~ 3 kJ mol). Synchronous fluorescence results corresponding to Trp and Tyr residues as well as FTIR spectra in the amide I region of LYS confirms minimal deformation in the LYS secondary structure on adsorption to spherical NP surface. Although the nature of LYS-drug interaction remains invariant, the extent of quenching interaction as well as the drug binding ability is strongly modulated in presence of NPs. Further, the antibacterial activity of LYS in presence of the investigated drugs shows 9-14% upsurge with AuNP, in sharp contrast to ca. 31-34% decrease in AgNP.

Isolation and characterization of actinomycetes from soil samples from altitudinal gradient of North-East India were investigated for computational RNomics based phylogeny. A total of 52 diverse isolates of Streptomyces from the soil samples were isolated on four different media and from these 6 isolates were selected on the basis of cultural characteristics, microscopic and biochemical studies. Sequencing of 16S rDNA of the selected isolates identified them to belong to six different species of Streptomyces. The molecular morphometric and physico-kinetic analysis of 16S rRNA sequences were performed to predict the diversity of the genus. The computational RNomics study revealed the significance of the structural RNA based phylogenetic analysis in a relatively diverse group of Streptomyces.