Synthesis,physicochemical characterization and biological activity of nano complexes of iron(III) of 3(2'‐hydroxyphenyl)‐5‐(4′‐substituted phenyl) pyrazolines and aspartic acid

Mixed ligand complexes of Iron(III) with aspartic acid and 3(2′‐hydroxy phenyl)‐5‐(4′‐substituted phenyl) pyrazolines of type [Fe(C₄O₄NH₆)₂(C₁₅H₁₂N₂OX)] and [Fe(C₄O₄NH₆)(C₁₅H₁₂N₂OX)₂], where (C₄O₄NH₆) = aspartate, (C₁₅H₁₂N₂OX) = deprotonated 3(2′‐hydroxyphenyl)‐5‐(4′‐substituted phenyl) pyrazolines (X = H, CH₃, OCH₃, Cl), have been synthesized. These newly synthesized derivatives have been physicochemically characterized by elemental analysis (C, H, N, Cl and Fe), magnetic moment data, thermogravimetric analysis, molar conductance, cyclic voltammetry, spectral analysis (UV–visible, IR, far IR and fast atom bombardment mass spectrometry). Scanning electron microscopy, transmission electron microscopy and X‐ray powder diffraction studies have been carried out for powdered samples, which show nanometric particles of these derivatives. Antibacterial and antifungal potential of free pyrazoline and some iron(III) complexes have been evaluated. Copyright © 2012 John Wiley & Sons, Ltd.     

Synthesis of on resin poly(propylene imine) dendrimer and its use as organocatalyst

Solid phase synthesis of poly(propylene imine) dendrimer is described. An iterative synthesis including double Michael addition of acrylonitrile to the primary amino groups on crosslinked polystyrene support followed by reduction of nitrile groups to amino groups give poly(propylene imine) dendrimers up to third generation attached to the polystyrene support. The supported dendrimer is used as an organocatalyst to Knoevenagel condensations. The supported catalyst showed good selectivity and the product was obtained in excellent yield under green reaction conditions. Densely packed amino groups enhance catalysis by a co-operative effect. The catalyst is recoverable and reusable.     

Fabrication of flexible conducting thin films of copper-MWCNT from multi-component aqueous suspension by electrodeposition

Flexible thin films of metal–carbon nanotube (CNT) with densely populated CNT morphology were fabricated by electrodeposition from an optimized copper bath. The substrate used for the present work is polyethylene film that was pre-deposited with electroless copper as a seed layer before CNT deposition. Optimum concentration of CNT was incorporated into copper bath and the electrodeposition was done at quiescent and agitation conditions. The bonding between the seed layer and the electrodeposited copper was good as revealed from adhesion test. Electrical as well as physical-mechanical property of the film was improved by CNT incorporation within the metal matrix. The topography and the texture of the metal–CNT deposit showed a well-refined structure as per scanning electron microscope (SEM), field emission scanning electron microscope (FE-SEM), and scanning probe microscope (SPM) analysis. The stability of the film was tested by cyclic voltammetric and stripping analysis under various applied conditions. Raman spectra and Fourier transfer infrared spectroscopic (FT-IR) analysis revealed the presence of CNT and the functionality of CNT within the copper matrix. Transmission electron microscope (TEM) analysis showed nucleation of copper on the surface of CNT walls.     

N-donor stabilized complexes of nickel(II) diphenyldithiophosphates: single-crystal X-ray,HSA and computational analysis

Transition Metal Chemistry - Nickel(II) complexes with octahedral coordination stabilized by N-donor ligands corresponds to [{(ArO)2PS2}2Ni·L2] [Ar = 4-(C2H5)C6H4 (3), and...     

Statistical Optimization for Succinic Acid Production from E. Coli in a Cost-Effective Medium

Response surface methodology (RSM) was employed for optimization of medium components and cultural parameters in cost effective cane molasses based medium for attaining high yield of succinic acid. The important factors obtained by “one-variable-at-a-time-approach” (cane molasses, corn steep liquor, sodium carbonate, and inoculum density) were further optimized by RSM. The optimum values of the parameters obtained through RSM (cane molasses 12.5%, corn steep liquor 7.5%, and sodium carbonate 25 mM) led to almost double yield of succinic acid (15.2 g/l in 36 h) as against “one-variable-at-a-time-approach” (7.1 g/l in 36 h) in 500-ml anaerobic bottles containing 300-ml cane molasses based medium. Subsequently, in 10-l bioreactor succinic acid production from Escherichia coli was further improved to 26.2 g/l in 30 h under conditions optimized through RSM. This fermentation-derived succinic acid will definitely help in replacing existing environmentally hazardous and cost-intensive chemical methods for the production of succinic acid.     

The temporal effect in listeners with mild to moderate cochlear hearing impairment

This study examines the relationship between a temporal masking effect and cochlear hearing impairment. The threshold level of a long-duration broadband masker needed to mask a short-duration tonal signal was measured for signals presented 2 ms (short-delay) or 202 ms (long-delay condition) after masker onset. The difference between these thresholds is the temporal effect. In two previous studies with normal-hearing listeners, estimates of gain of the cochlear active process derived from such data suggested a decrease in gain during the course of the masker. This hypothesis was further examined in the present study by testing listeners with mild to moderate cochlear hearing impairment. Results are consistent with a decrease in gain in the short-delay condition with increasing hearing impairment, and also less change in gain with increasing hearing impairment.     

Controlled induction, enhancement, and guidance of neuronal growth cones by use of line optical tweezers

We report an optical tweezers based approach for efficient and controlled manipulation of neuronal growth cones. The approach exploits asymmetric transverse gradient force created in a line optical tweezers to transport actin monomers in the desired growth direction. With this approach induction of artificial growth cones from the neuronal cell body and enhancement of the growth rate of the natural growth cones have been achieved. The use of this approach to bring two growth cones into close proximity for establishing a neuronal connection is also discussed.     

Chitosan as a macroaffinity ligand purification of chitinases by affinity precipitation and aqueous two-phase extractions

(1) Chitosan was found to be a suitable macroaffinity ligand for affinity precipitation of chitinase from Neurospora crassa, cabbage and puffballs. (2) The activity recoveries of 85, 82 and 90% with concomitant fold purifications in terms of specific activities were 27, 15 and 30 with N. crassa, cabbage and puffballs and were obtained with affinity precipitation. These results were obtained with clarified extracts/homogenates as the starting materials. (3) The incorporation of chitosan in poly(ethylene glycol) (PEG)-salt aqueous two-phase system allowed purification of chitinases from these sources directly from unclarified extracts/homogenates. (4) The 96% (w/v) chitosan (of initially introduced into the aqueous two-phase system) partitioned into PEG-phase and this enhanced the partitioning of chitinases into PEG-phase. The chitosan, free as well as bound to chitinases, could be separated from PEG-phase by increasing the pH to 7. (5) By the process of desorption with 2.0 M MgCl2, 86, 80 and 88% activity recoveries (% expressed in terms of total units of enzyme activities in the crude extract) were obtained in the case of N. crassa, cabbage and puffballs, respectively. The corresponding fold purifications in terms of specific activities were 34, 20 and 38. (6) The purified preparations gave single bands on sodium dodecyl sulfate-polyacrylamide gel electrophoresis and the estimated molecular masses agreed with the reported values in the literature.