Crocetin from the tubular calyx of Nyctanthes arbor-tristis

A carotenoid aglycone Ag-NY1 was isolated from the orange coloured tubular calyx of flowers of Nyctanthes arbor-tristis. The elucidation of the structure through a detailed spectroscopic study revealed that the carotenoid molecule is crocetin, which is the major aglycone present in the stigma of Crocus sativus. The compound exhibited a good membrane stabilising activity as compared to the corresponding glycoside crocin.     

Mechanical characterization of sintered piezo-electric ceramic material using scanning acoustic microscope

Lead Zirconate Titanate (PZT) is a piezo-electric ceramic material that needs to be characterized for its potential use in microelectronics. Energy dispersive X-ray analysis (EDX) is conducted to determine the chemical composition of the PZT ceramics. The scanning electron microscope (SEM) is performed to study the surface morphology, grain structure and grain boundaries. The SEM image helps us to understand the surface wave propagation and scattering phenomena by the PZT and the reason for its anisotropy and inhomogeneity due to the grain structure. In this paper scanning acoustic microscopy at 100 MHz excitation frequency is conducted for determining mechanical properties of PZT. Earlier works reported only the longitudinal wave speed in PZT while in this paper longitudinal, shear and surface acoustic wave speeds of sintered PZT are measured from its acoustic material signature (AMS) curves, also known as V(z) curves. AMS or V(z) curve is the variation of the output voltage as a function of the distance between the acoustic lens focal point and the reflecting surface. The average velocities of longitudinal, shear and surface acoustic waves in a PZT specimen are determined from its V(z) curve generated at 100 MHz excitation frequency and found to be over 5000 m/s, over 3000 m/s and between 2500 and 3000 m/s, respectively. From these velocities all elastic constants of the specimen are obtained.     

Synthesis and Antimicrobial Activities of Novel Series of 1-((4-Methyl-2-Substituted Thiazol-5-yl)Methyleneam INO)-2-Substituted Isothiourea Derivatives

A novel series of 1-((4-methyl-2-substituted thiazol-5-yl)methyleneamino)-2-substituted isothiourea derivatives was synthesized by alkylation of (Z/E)-1-((4-methyl-2-substituted thiazol-5-yl)methylene)thiosemicarbazide with alkylhalide in acetone. All the newly synthesized compounds were characterized by spectral (IR, ¹H NMR, ¹³C NMR, and mass spectrometry) methods. The newly synthesized compounds were screened for in vitro antimicrobial activity. Most of the compounds show moderate to excellent antimicrobial activity.

[Supplementary materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfer, and Silicon and the Related Elements for the following free supplemental files: Additional figures and tables.]     

A simple model for a two-stage chemical reaction with diffusion

We analyse the evolution of a two-stage chemical reaction betweentwo neighbouring plumes of reactants. Under the assumption thatthe plumes are approximately Gaussian we derive a system ofordinary differential equations for the total amount, the centroidand the variance of each reactant. We compare the solution ofthese equations with full numerical simulation of the reaction.Excellent agreement is obtained, with solution of the near-Gaussianmodel requiring considerably less computational effort thanthe full simulations. Of key importance is the yield of thereaction, and we discuss this feature in particular.     

Structural, optical and electrical properties of cadmium zinc oxide films for light emitting devices

Structural, optical and electrical properties of Cd_yZn_1-yO (y=0–0.1) ternary alloy thin films have been investigated for the films prepared using the spin coating method on the glass substrate. XRD pattern confirmed the nano-size polycrystalline hexagonal wurtzite structure for all the samples. The size of nano-crystals was found to be varied in between 21 and 30 nm. Optical band gap calculated from the absorption coefficient signifies the shift in direct band gap from 3.2 to 2.97 eV with cadmium composition. Through EDAX spectrum, it was confirmed that Cadmium was successfully incorporated into ZnO. SEM studies make clear that even after Cadmium incorporation, the surface morphology of the films remained smooth. The current–voltage characteristics obtained from semiconductor characterization system reveals that resistance of the films was found to be decreased with the increase in cadmium composition. Our investigations lead to the applicability of CdZnO as an active layer in CdZnO/ZnO heterostructure for light emitting devices.     

Crystal structure,DFT study,and Hirshfeld surface analysis of ethyl 5-(3,4-dimethoxyphenyl)-7-methyl-3-phenyl-5<Emphasis Type="Italic">H</Emphasis>-thiazolo[ 3,2-A]pyrimidine-6-carboxylate

The structural characterization of fused thiazolopyrimidine 1 (C₂₄H₂₄N₂O₄S) is performed using the single crystal X-ray study, the DFT calculation, and the Hirshfeld surface analysis. The molecular packing of the crystal is mainly stabilized by C–H…O and C–H…π interactions. A DFT calculated HOMO-LUMO energy gap of 3.90 eV indicates a high kinetic stability of the compound. The 3D Hirshfeld surfaces and the associated 2D fingerprint plots are investigated for short contact interactions. The relative contribution of different interactions to the Hirshfeld surface indicates that the H…H, C…H, and O…H contacts account for about 83.4% of the total Hirshfeld surface area.     

Sensitivity enhancement in saturation transfer difference (STD) experiments through optimized excitation schemes

Investigation of ligand-protein interactions by the saturation transfer difference (STD) experiment has been well established in the drug discovery process through numerous examples. Thus, binding epitopes may be mapped by comparing signals of the ligand with and without saturation of the protein. Herein, it is shown that a less selective process allows more protons to assist in the saturation of the protein, thereby considerably enhancing the sensitivity of the STD experiment. Increasing the saturation power entails a greater risk of perturbing the ligand; however, an amplitude modulation of the waveform assists this procedure by distributing the applied energy in sidebands.     

Gas-phase deprotonation of arylalkylamines. A collision-induced dissociation study

The collision-induced dissociation (CID) of deprotonated arylalkylamines of general formula R(1)C(6)H(4)CHR(2)CH(2)NR(3)(2) (where R(1) = H, OH, F or NO(2); R(2) = H or OH; R(3) = H or CH(3)) generated by negative chemical ionization with H(2)O and D(2)O as ionizing reagents, is discussed. The negative chemical ionization mass spectra show that, in the absence of a hydroxy group in the aromatic ring, deprotonation takes place at the benzylic position whereas the proton is lost from the OH group when present. The nitro compound forms only M(-.) ions. The CID spectra of the deprotonated molecules show that fragmentations are strongly dependent on the structural features of the molecules, namely the presence or absence of substituents in the aromatic ring or aliphatic chain. Copyright 1999 John Wiley & Sons, Ltd.     

Development of a new chromogenic spray reagent for the detection and identification of synthetic pesticide carbaryl in biological material by high-performance thin-layer chromatography

JPC – Journal of Planar Chromatography – Modern TLC -