A new lawsone azo-dye for optical sensing of Fe3+ and Cu2+ and their DFT study

A new lawsone-based azo-dye 2-hydroxy-3-((pyridin-2-ylmethyl)diazenyl)naphthalene-1,4-dione (1) was synthesized and applied for sensing of metal ions. Receptor 1 showed selective fluorescent and colorimetric response for the detection of Cu²⁺ and Fe³⁺ over other tested metal ions. The fluorescence intensity of 1 was significantly quenched allowing detection of Fe³⁺ and Cu²⁺ down to 0.61 and 6.06 μM, respectively. The binding has been established by fluorescence spectroscopic method. Receptor 1 provided a 1?:?1 binding scaffold for recognition of Fe³⁺ and Cu²⁺ ions with the association constant of 3.33 × 10⁶ and 3.33 × 10⁵ M^?1, respectively. The B3LYP/6-31G/LANL2DZ method was employed for the optimization of 1 and 1·Fe³⁺ and 1·Cu²⁺.     

2-D finite element analysis of rigid pavement considering dynamic vehicle–pavement interaction effects

In the present study, an improved solution algorithm based on Finite Element Method for dynamic analysis of rigid pavements under moving loads is presented incorporating vehicle–pavement interaction which is having significant effect on the response. The concrete pavement is discretized by finite and infinite plate elements. The underlying soil medium is modeled by Pasternak model. An attempt is made to consider the infinite extent of the pavement with introduction of infinite elements at both ends. A detailed study is carried out for the range of velocities for pavements of finite and infinite lengths resting on two parameter soil medium. The effect of soil modulus, shear modulus, pavement thickness and the vehicle–pavement interaction on the response of pavement is presented. Relationships are suggested in non-dimensional form to predict critical velocity and maximum deflection for three prominent peaks in case of analysis without VPI and first critical velocity range of analysis with VPI. Predicted values using these relationships are in good agreement with the actual values. The comparison between the response of finite and infinite pavement lengths revealed that the deflections are decreased and the critical velocity range is narrowed in case of pavements of infinite length.     

Tetramisole-Chromium Trioxide Complex: A New Oxidant of Organic Compounds @

Tetramisole has been found to complex with chromium trioxide. Elemental analysis suggests a 1:1 complex formation and IR data suggest the ligand binding through N-7 nitrogen. The new complex is capable of selectively oxidizing alcohols, including benzyl and allylic alcohol, to carbonyl compounds under mild conditions.

     

Polyvinyl alcohol/acrylamide based photopolymer composition as recording medium for high‐resolution volume‐phase holograms

A polyvinyl alcohol/acrylamide based photopolymer composition that can be used to record holograms (at 532 nm) with ~92% diffraction efficiency and stability extending over a period of several months has been prepared. This system has been investigated earlier but with limitations of diminishing grating efficiency as a function of time and humidity. In the present work, we have successfully addressed these problems. In this work, crosslinkers have been added both for monomer and binder, and the effect of this addition and concentrations of various components of the composition on the diffraction efficiency and recording energy has been studied. It was found that an optimum concentration exists for each component at which diffraction efficiency is the maximum and recording energy the minimum. It was also observed that addition of a crosslinking monomer improved the grating efficiency. Crosslinking of the binder further improved the grating efficiency and its stability over time and under high humidity conditions. Maximum possible resolution for this photopolymer has been found to be 2000 lines/mm. Copyright © 2011 John Wiley & Sons, Ltd.     

Preparation,thermal, XRD,chemical and FTIR spectral analysis of NiMn<Subscript>2</Subscript>O<Subscript>4</Subscript> nanoparticles and respective precursor

Samples of water based commercial acrylic resin paints were spread in a film form on slides, dried at room temperature and exposed to solar radiation for up to eight months. The characterization and quantification of resins and charges in the white paint emulsion were carried out for the thermal decomposition. Besides this, X-ray diffractometry was used to identify CaCO₃ as charge and TiO₂ (rutile phase) as pigment. It was observed through thermal techniques similar behavior to the samples even though with varied exposure time. Kinetic studies of the samples allowed to obtain the activation energy (E _a) and Arrhenius parameters (A) to the thermal decomposition of acrylic resin to three different commercial emulsion (called P₁, P₂, P₃) through non-isothermal procedures. The values of E _a varied regarding the exposition time (eight months) and solar radiation from 173 to 197 kJ mol⁻¹ (P₁ sample), from 175 to 226 kJ mol⁻¹ (P₂ sample) and 206 to 197 kJ mol⁻¹ (P₃ sample). Kinetic Compensation Effect (KCE) observed for samples P₂ and P₃ indicate acrylic resin s present in these may be similar in nature. This aspect could be observed by a small difference in the thermal behavior of the TG curves from P₁ to P₂ and P₃ sample. The simulated kinetic model to all the samples was the autocatalytic Šesták-Berggreen.     

Donepezilium oxalate trihydrate,a therapeutic agent for Alzheimer's disease

Donepezil, a cholinesterase inhibitor with good central nervous system penetration, has been crystallized as a tertiary amine salt with a disordered oxalate anion to give the title compound, (R,S)‐1‐benzyl‐4‐[(5,6‐dimethoxy‐1‐oxoindan‐2‐yl)methyl]piperidinium hydrogen oxalate trihydrate, C₂₄H₃₀NO₃⁺·C₂HO₄⁻·3H₂O. The indanone and piperidine ring planes are inclined at an angle of 33.4 (1)°. A comparison is made with the piperidinium cation bound in acetyl­cholinesterase in the solid state. The methyl­ene units bridging the indanone–piperidine–benzyl groups determine the mol­ecular shape and conformational features. The structure is stabilized mainly by O—H⋯O and N—H⋯O hydrogen bonds, with water mol­ecules mediating inter­actions between oxalate anions and donepezilium cations.     

Potential of Kalopanax septemlobus Leaf Extract in Synthesis of Silver Nanoparticles for Selective Inhibition of Specific Bacterial Strain in Mixed Culture

Silver nanoparticles (AgNPs) were synthesised using Kalopanax septemlobus plant leaf extracts. UV-visible spectrophotometric, Fourier-transform infrared, electron dispersive X-ray spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses confirmed synthesis of AgNPs. TEM micrographs revealed presence of well-dispersed AgNPs predominantly of small size and different shapes with an average particle size of 30.8 nm. Antimicrobial susceptibility tests of AgNP treatments revealed variability in sensitivity of bacteria Bacillus cereus and Saccharophagus degradans under study. Minimum inhibitory concentration (MIC) values of the AgNPs for B. cereus and S. degradans were found to be 30 and 10 μg/mL, respectively. The mixed culture of B. cereus and S. degradans treated with AgNPs at 10 μg/mL showed increase in growth with time, suggesting survival of bacteria in liquid media. The plating of mixed culture before AgNP treatment showed presence of both bacteria, but 24-h-old mixed culture treated with AgNPs at the concentration of 10 μg/mL showed presence of B. cereus colonies. SEM micrographs revealed damage to S. degradans cells but no effect on B. cereus cells after AgNP treatment. Confocal microscopic observations of AgNP-treated mixed cultures by Nile blue A staining indicated intact polyhydroxyalkanoates producing flourescent cells of B. cereus but damage and deformities in S. degradans cells. This study suggests that AgNPs can selectively inhibit growth of S. degradans and retain B. cereus at MIC of S. degradans. This report is a case study for selective inhibition of one bacteria and growth of the other in a culture using plant-synthesized silver nanoparticles.     

Development of ion chromatography and capillary electrophoresis methods for the determination of Li in Li–Al alloy

Two methods were developed for determination Li content in Li–Al alloy by employing ion chromatography (IC) and capillary electrophoresis (CE) without any prior separation of Al matrix. In absence of suitable certified reference material the two methods were used to validate each other. Using a high capacity column and a weaker eluent methane sulphonic acid, it was possible to separate Li in IC without eluting strongly retained Al. The method showed good precision and sensitivity and was extended for analysis of routine samples. In the case of CE using imidazole as co-ion, Li was detected in CE by indirect detection. In view of no interference from Al, samples were analyzed without any matrix separation. The CE method was used successfully for sample analysis and results were compared with IC results.