Tuning the diglycolamides for modifier-free minor actinide partitioning

The unsymmetrical diglycolamides (DGAs) such as N,N-dihexyl-N′,N′-dioctyl-3-oxapentane-1,5-diamide (DHDODGA), N,N-didecyl-N′,N′-dioctyl-3-oxapentane-1,5-diamide (D²DODGA), N,N-didodecyl-N′,N′-dioctyl-3-oxapentane-1,5-diamide (D³DODGA), were synthesized, and characterized by IR, NMR, and mass spectroscopic techniques. The extraction behaviour of Am(III), Eu(III), and Sr(II) by the solutions of these unsymmetrical DGAs in n-dodecane was studied as a function of concentration of nitric acid and DGA. The distribution ratio of Am(III) and Eu(III) increased with increase in the concentration of nitric acid; whereas, the distribution ratio of Sr(II) reached a maximum at 4 M nitric acid followed by decrease at higher acidities. The extraction of Am(III) and Eu(III) in 0.1 M DGA/n-dodecane decreased in the order DHDODGA > D²DODGA > D³DODGA. However, the order changed upon lowering the concentration of DGA. The third-phase formation behaviour of nitric acid and neodymium(III) in 0.1 M DGA/n-dodecane was studied as a function of concentration of nitric acid. The limiting organic concentration of nitric acid and neodymium increased with increase in the chain length of alkyl group attached to amidic nitrogen. Near stoichiometric amount of neodymium(III) was loaded in 0.1 M D³DODGA/n-dodecane without the formation of third-phase from 3 to 4 M nitric acid medium. The study revealed that the unsymmetrical diglycolamides D²DODGA and D³DODGA are superior candidates for partitioning the minor actinides from high-level liquid waste.     

Novel Approach to the Synthesis of (R,S)‐Baclofen via PD(II)‐Bipyridine–Catalyzed Conjugative Addition

Synthesis of (R,S)‐baclofen is described starting from N‐phthalimidoacetaldehyde. The key step in the synthesis was Pd(II)‐bipyridine–catalyzed conjugative addition of 4‐chloroboronic acid.     

Efficient Aromatization of 4,5-Dihydro-3(2H)-Pyridazinones Substituted at 5 Position by Using Anhydrous Copper (II) Chloride

An efficient conversion of 5-substituted-4,5-dihydro-3(2H)-pyridazinones into their corresponding dehydrogenated derivatives was achieved by treatment with anhydrous copper(II) chloride in acetonitrile.     

Modelling of binding free energy of targeted nanocarriers to cell surface

We have developed a numerical model based on Metropolis Monte Carlo and the weighted histogram analysis method that enables the calculation of the absolute binding free energy between functionalized nanocarriers (NC) and endothelial cell (EC) surfaces. The binding affinities are calculated according to the free energy landscapes. The model predictions quantitatively agree with the analogous measurements of specific antibody coated NCs (100 nm in diameter) to intracellular adhesion molecule-1 (ICAM-1) expressing EC surface in in vitro cell culture experiments. The model also enables an investigation of the effects of a broad range of parameters that include antibody surface coverage of NC, glycocalyx in both in vivo and in vitro conditions, shear flow and NC size. Using our model we explore the effects of shear flow and reproduce the shear-enhanced binding observed in equilibrium measurements in collagen-coated tube. Furthermore, our results indicate that the bond stiffness, representing the specific antibody–antigen interaction, significantly impacts the binding affinities. The predictive success of our computational protocol represents a sound quantitative approach for model driven design and optimization of functionalized NC in targeted vascular drug delivery.     

Application of neural networks with novel independent component analysis methodologies for the simultaneous determination of cadmium,copper, and lead using an ISE array

The paper introduces a novel chemometric strategy based on independent component analysis (ICA) coupled with a back‐propagation neural network. In this approach, one of the most popular ICA methods, the fast fixed‐point algorithm for ICA (fastICA), was implemented by the genetic algorithm (geneticICA) to avoid the local maxima problem commonly observed with fastICA. As a case study, an ion‐selective electrode (ISE) array, consisting of three working electrodes and one reference electrode, was used for the simultaneous determination of three heavy metals (cadmium, copper, and lead) in aqueous solutions, which are normally prone to severe interferences. The robustness and appropriateness of the approach were assessed using the average mean of relative error (MRE) of triplicated external validation. After configuration and optimization, the average MRE for Cu was <5%. For the determination of Cd and Pb, whose ISEs normally cannot tolerate Cu ions even at the microgram per liter levels, the MREs were 8%. This article demonstrated that this approach can be applied to the detection of heavy metal contamination in industrial wastewater with prediction accuracies comparable with other popular quantitative chemometric neural network methods. Copyright © 2014 John Wiley & Sons, Ltd.     

Studies on highly resistive ZnO thin films grown by DC-discharge-assisted pulsed laser deposition

It was found that by changing the substrate temperature from room temperature to ～850 °C, ZnO thin films with widely varying resistivity values could be grown on sapphire substrates using DC-discharge-assisted pulsed laser deposition (PLD) in oxygen ambient. The resistivity of the film grown at room temperature was too high to measure using our existing setup. However, as the growth temperature was increased from 550 °C to 750 °C, the resistivity first decreased slowly from ～14.0 to 4.4 Ω?m and then dropped suddenly to get saturated at ～2.0×10^?3 Ω?m as the growth temperature was further increased. In contrast to these, when there was no DC-discharge, the variation of resistivity for ZnO thin films grown by PLD was marginal up to the substrate temperature of ～850 °C. The reason for these observations was found to be the combined effects of reduction in donor defect densities like oxygen vacancies and zinc interstitials, introduction of acceptor type defects like interstitial oxygen and zinc vacancies, and the resultant poor carrier mobility at lower growth temperatures. At higher growth temperatures (800 °C and above), the appearance of oxygen vacancies and increase in mobility due to better crystalline quality were found to be responsible for reducing the resistivity. The PL of these films had significant emission in the green and red regions of the spectrum due to the aforesaid defect related transitions. Such highly resistive and luminescent films might be suited for applications such as resistive RAM, UV-photo detector, TFT, piezoelectric, transparent phosphor, and broadband LED applications.     

Computational discovery of putative quorum sensing inhibitors against LasR and RhlR receptor proteins of Pseudomonas aeruginosa

Drugs have been discovered in the past mainly either by identification of active components from traditional remedies or by unpredicted discovery. A key motivation for the study of structure based virtual screening is the exploitation of such information to design targeted drugs. In this study, structure based virtual screening was used in search for putative quorum sensing inhibitors (QSI) of Pseudomonas aeruginosa. The virtual screening programme Glide version 5.5 was applied to screen 1,920 natural compounds/drugs against LasR and RhlR receptor proteins of P. aeruginosa. Based on the results of in silico docking analysis, five top ranking compounds namely rosmarinic acid, naringin, chlorogenic acid, morin and mangiferin were subjected to in vitro bioassays against laboratory strain PAO1 and two more antibiotic resistant clinical isolates, P. aeruginosa AS1 (GU447237) and P. aeruginosa AS2 (GU447238). Among the five compounds studied, except mangiferin other four compounds showed significant inhibition in the production of protease, elastase and hemolysin. Further, all the five compounds potentially inhibited the biofilm related behaviours. This interaction study provided promising ligands to inhibit the quorum sensing (QS) mediated virulence factors production in P. aeruginosa.     

Zirconium Complexes of Two Different Iminopyrrolyl Ligands – Syntheses and Structures

The reaction involving N‐aryliminopyrrolyl ligand, 2‐((p‐Me‐C₆H₃N=CMe)–C₄H₃NH) ( 1a ) (Imp^Me‐H), and Zr(OtBu)₄ in a 2:1 molar ratio in toluene at 90 °C afforded the corresponding bis(iminopyrrolyl) complex of zirconium, [(Imp^Me)₂Zr(OtBu)₂] ( 2a ) having two bidentate iminopyrrole groups in the coordination sphere. In contrast, the bulkier 2‐((2,6‐iPr₂C₆H₃N=CH)–C₄H₃NH) ( 1b ) (Imp^Dipp‐H) and Zr(OtBu)₄ in a 1:1 molar ratio under the same condition yielded the corresponding mono(iminopyrrolyl) complex of zirconium, [(Imp^Dipp)Zr(OtBu)₃(THF)] ( 2b ), which contains only one bidentate iminopyrrole moiety in the coordination sphere. Both complexes were characterized by single‐crystal X‐ray diffraction analysis. The solid‐state structures reveal that the bulky iminopyrrole ligands cause a steric crowding around the zirconium ion along with three tert‐butoxide ligands attached to the central metal atom.