Validated High-Performance Thin-Layer Chromatographic Method for the Simultaneous Determination of Quercetin,Rutin, and Gallic Acid in Amaranthus tricolor L.

JPC – Journal of Planar Chromatography – Modern TLC - A simple, rapid, quantitative, and validated high-performance thin-layer chromatographic (HPTLC) method has been developed for the...     

Redox‐Active Peptide‐Functionalized Quinquethiophene‐Based Electrochromic π‐Gel

An electrochromic system based on a self‐assembled dipeptide‐appended redox‐active quinquethiophene π‐gel is reported. The designed peptide‐quinquethiophene consists of a symmetric bolaamphiphile that has two segments: a redox‐active π‐conjugated quinquethiophene core for electrochromism, and peptide motif for the involvement of molecular self‐assembly. Investigations reveal that self‐assembly and electrochromic properties of the π‐gel are strongly dependent on the relative orientation of peptidic and quinquethiophene scaffolds in the self‐assembly system. The colors of the π‐gel film are very stable with fast and controlled switching speed at room temperature.     

One-Pot Dual C−C Coupling Reaction via Site Selective Cascade Formation by PdII-Cryptate of an Amino-Ether Heteroditopic Macrobicycle

Selectivity of aryl iodo over ethynyl iodo toward the Suzuki cross coupling reaction is explored by utilizing a palladium complex of amino-ether heteroditopic macrobicycle. Subsequently, unreacted ethynyl iodide undergoes homocoupling reaction in the same catalytic atmosphere, thereby representing a cascade dual C−C coupling reaction. Furthermore, this approach is extended for novel one-pot synthesis of unsymmetrical 1,3-diynes.     

Synthesis, biological evaluation and in silico metabolic and toxicity prediction of some flavanone derivatives

Flavones chemically are anthoxanthins, occur either in the free state or as glycosides associated with tannins (flavanoids). Flavanoids (derivatives of flavone) possess various pharmacological activities and due to its xanthine-oxidase enzyme inhibitory effect it also has superoxide-scavenging activities. A series of 2-phenyl-2,3-dihydrochromon-4-one derivatives (flavanone derivatives) were synthesized from chalcones by cyclization method and their activities were evaluated against some gram positive and gram-negative bacteria. IR, NMR and CHN analysis confirmed the structure of the synthesized compounds. The results of the antibacterial studies shows that compounds 2b, 2e, 2f and 2h possess activity against many bacterial strains. Among that the compound (2h) has remarkable activity against all strains viz. 25 microg/ml inhibitory concentration against S. aureus, S. sonnei, E. coli, S. typhimurium and V. cholerae. Compound 2f possess minimum inhibitory concentration of 200 microg/ml against E. coli and S. typhimurium and 25 microg/ml against S. sonnei, S. dysenteriae and V. cholerae. In silico metabolic and toxicity study of the synthesized compounds were performed and the predicted result showed that the compound having hydroxyl functional group undergo sulfate and O-glucuronide conjugation reaction and methoxy derivatives undergo demethylation reaction. The biologically active compounds are free of toxicity in oncogene, teratogen, sensitivity and immunotoxicity.     

Characterizing chaos and multifractality in noise-assisted tumor-immune interplay

Nonlinear Dynamics - We propose a noise-assisted tumor-immune system based on the Wiener process. Stochastic sensitivity and chaos both are studied with the variations of noise strengths. The...     

Channeling and axial to planar channeling transition of protons in magnesium oxide

The channeling of 1.7 MeV protons along 〈100〉 axial direction, (100), (110) and (111) planar directions in magnesium oxide single crystals and axial to planar channeling transitions from 〈100〉 to (100), (110) and (210) have been studied experimentally. The experimental data and preliminary analysis of results are presented.     

Phase synchronization of instrumental music signals

Signal analysis is one of the finest scientific techniques in communication theory. Some quantitative and qualitative measures describe the pattern of a music signal, vary from one to another. Same musical recital, when played by different instrumentalists, generates different types of music patterns. The reason behind various patterns is the psycho-acoustic measures – Dynamics, Timber, Tonality and Rhythm, varies in each time. However, the psycho-acoustic study of the music signals does not reveal any idea about the similarity between the signals. For such cases, study of synchronization of long-term nonlinear dynamics may provide effective results. In this context, phase synchronization (PS) is one of the measures to show synchronization between two non-identical signals. In fact, it is very critical to investigate any other kind of synchronization for experimental condition, because those are completely non identical signals. Also, there exists equivalence between the phases and the distances of the diagonal line in Recurrence plot (RP) of the signals, which is quantifiable by the recurrence quantification measure τ-recurrence rate. This paper considers two nonlinear music signals based on same raga played by two eminent sitar instrumentalists as two non-identical sources. The psycho-acoustic study shows how the Dynamics, Timber, Tonality and Rhythm vary for the two music signals. Then, long term analysis in the form of phase space reconstruction is performed, which reveals the chaotic phase spaces for both the signals. From the RP of both the phase spaces, τ-recurrence rate is calculated. Finally by the correlation of normalized tau-recurrence rate of their 3D phase spaces and the PS of the two music signals has been established. The numerical results well support the analysis.     

Intricate packing in the hydrophobic core of barstar through a CH–π interaction

Identification of specific packing interactions within in the hydrophobic core of proteins is important for understanding the integrity of protein structure. Finding such interactions is challenging because few tools allow monitoring of a specific interaction in the presence of several non‐specific forces that hold proteins together. It is important to understand how and when such interactions develop during protein folding. In this study, we have used the intrinsic tryptophan residue, Trp53, as an ultraviolet resonance Raman probe to elucidate the packing interactions in the hydrophobic core of the protein barstar. Barstar is extensively studied for its folding, unfolding and aggregation properties. The Trp53 residue is known to be completely buried in the hydrophobic core of the protein and is used extensively as an intrinsic probe to monitor the folding and unfolding reactions of barstar. A comparison of the resonance Raman cross sections of some bands of Trp53 with those observed for N‐acetyl‐tryptophanoamide in water suggests that Trp53 in barstar is indeed isolated from water. Intensity ratio of the Fermi doublet suggests that Trp53 is surrounded by several aliphatic amino acid residues in corroboration with the crystal structure of barstar. Importantly, we show that the side chain of Trp53 is involved in a unique CH–π interaction with CH groups of Phe56 as well as a steric interaction with the methyl group of Ile5. Copyright © 2014 John Wiley & Sons, Ltd.     

Fréchet Means for Distributions of Persistence Diagrams

Given a distribution \(\rho \) on persistence diagrams and observations \(X_{1},\ldots ,X_{n} \mathop {\sim }\limits ^{iid} \rho \) we introduce an algorithm in this paper that estimates a Fréchet mean from the set of diagrams \(X_{1},\ldots ,X_{n}\) . If the underlying measure \(\rho \) is a combination of Dirac masses \(\rho = \frac{1}{m} \sum _{i=1}^{m} \delta _{Z_{i}}\) then we prove the algorithm converges to a local minimum and a law of large numbers result for a Fréchet mean computed by the algorithm given observations drawn iid from \(\rho \) . We illustrate the convergence of an empirical mean computed by the algorithm to a population mean by simulations from Gaussian random fields.