Electronic structure, phonons, and dielectric anomaly in ferromagnetic insulating double pervoskite La2NiMnO6

Using first-principles density functional calculations, we study the electronic and magnetic properties of the ferromagnetic insulating double perovskite compound La2NiMnO6, which has been reported to exhibit an interesting magnetic field sensitive dielectric anomaly as a function of temperature. Our study reveals the existence of very soft infrared active phonons that couple strongly with spins at the Ni and Mn sites through modification of the superexchange interaction. We suggest that these modes are the origin for the observed dielectric anomaly in La2NiMnO6.     

Facile one-pot synthesis,butyrylcholinesterase and α-glucosidase inhibitory activities,structure–activity relationship,molecular docking and DNA–drug binding analysis of Meldrum’s acid derivatives

Research on Chemical Intermediates - Meldrum’s acid derivatives were facile synthesized by one-pot condensation process and characterized by NMR (1H, 13C, DEPT-90 and DEPT-135) and EI-MS. The...     

Enhanced skin permeation of diclofenac by ion-pair formation and further enhancement by microemulsion

Enhancement of skin permeability of anionic diclofenac from non-aqueous vehicle isopropyl myristate (IPM) by ion-pair formation with either alkylamines or benzylamine as model cationic ions was examined in guinea pig dorsal skin. Diclofenac ion flux increased in the presence of these amines due to an increase in solubility. Maximum flux was observed in the presence of n-hexylamine, which induced 7.3-fold increase accompanied by a 45-fold increase in solubility. Permeability coefficients of the ionic form of diclofenac in the presence of benzylamine, n-hexylamine and iso-octylamine as counter ions in IPM were larger than those of the non-ionic form of diclofenac. Since the solubility of diclofenac was still limited, to obtain further enhancement of skin permeation, the effects of microemulsions as a vehicle consisting of phosphate buffered saline (PBS), isopropyl myristate (IPM), polyoxyethylene sorbitan monooleate (Tween 80) and ethanol were examined for transport of diclofenac-benzylamine ion-pairs. All microemulsion formulations tested increased diclofenac flux 4.9-fold to 10.7-fold over the value without a microemulsion accompanied by a 217-fold to 302-fold improvement in the solubility of diclofenac-benzylamine ion-pairs, but permeability coefficients were decreased 28-44 fold. Maximum enhancement was observed for a microemulsion with a ratio of PBS, IPM, ethanol and Tween 80 of 25 : 8 : 47 : 20 (w/w). The present findings suggest the usefulness of combined use of ion-pairs with microemulsions for enhancement of skin permeation of ionic drugs.     

Enhanced skin permeation of salicylate by ion-pair formation in non-aqueous vehicle and further enhancement by ethanol and l-menthol

Enhancement of skin permeability of salicylate from non-aqueous vehicle by ion-pair formation with either alkylamines or benzylamine as model cationic ions was examined in excised guinea pig dorsal skin. Solubility of salicylate in isopropyl myristate (IPM) was increased by the addition of either alkylamines or benzylamine as counter ions. The increase was more significant in the presence of amines with longer alkyl chains. Flux of salicylate increased in the presence of these amines due to the increase in the solubility. Maximum flux was observed in the presence of n-hexylamine, which induced an 11-fold increase due to 137-fold increase in solubility. Flux and permeability coefficients of salicylate in the presence of n-butylamine, n-hexylamine, iso-octylamine and benzylamine as counter ions in IPM were larger than those of the non-ionic form of salicylic acid. Flux of 3-methylsalicylate (3-CH3 substituent) and that of 5-hydroxysalicylate (5-OH substituent) were smaller than that of salicylate in the presence of n-hexylamine. After partition to the skin surface, the ion-pair is suggested to dissociate and permeate separately according to the study using lidocaine as the counter ion. Flux of salicylate increased in the presence of benzylamine as the counter ion by the addition of 15% ethanol and 15% ethanol plus 1% l-menthol due to further improvement in the solubility as well as an increase in the permeability coefficient.     

Identification and Separation of Lead (II), Nickel (II), and Cobalt (II) on Silica Gel 60 F254 High-Performance Thin-Layer Chromatographic Plates with Mixed Aqueous Sodium Dodecyl Sulfate—Oxalic Acid Solvent System

JPC – Journal of Planar Chromatography – Modern TLC - The chromatographic separation of three metal cations was performed on high-performance thin-layer plates (silica gel 60F254) with...     

A Study on Oscillatory and Asymptotic Nature of Impulsive Neutral Differential Equations of Order Three

In this paper, we consider a class of third-order neutral impulsive differential equations. An equivalent class of neutral differential equations is obtained by using a suitable substitution. Some new oscillation results are proved. Moreover, we discuss the asymptotic behavior of the solution. The results presented here are illustrated via examples.     

Potentiometric studies on mixed-ligand complexes of cobalt(II) and nickel(II) with amino acids as primary ligands and imidazole as secondary ligand

Summary The formation constants of mixed-ligand complexes of cobalt(II) and nickel(II) with glycine, DL--alanine and DL-valine as primary ligands and imidazole as secondary ligand have been determined potentiometrically under physiological-like conditions (T=37°C and I=0.15 M KNO₃). The proton association constants of the free ligands and the stability constants for binary systems involving the amino acids and imidazole were also determined under identical conditions, and the experimental pH-titration data were analysed using the computer SUPERQUAD program. The relative stability of the ternary complex as compared to that of the corresponding binary complexes has been quantitatively expressed in terms of log K and log X values.     

Potentiometric studies on mixed-ligand complexes of copper(II) and zinc(II) with some amino acids (glycine,DL-α-alanine and DL-valine) as primary ligands and imidazole as a secondary ligand

Summary Mixed-ligand complexes of Cu^II and Zn^II with glycine(GL), DL--alanine (AL) and DL-valine (VL) as primary ligands and imidazole (IM) as secondary ligand have been studied potentiometrically under physiological conditions (t=37° C and I=0.15 M KNO₃). The experimental pH-titration data were analysed with aid of the SUPERQUAD computer program in order to evaluate formation constants of binary and ternary systems involying amino acids (AA) and IM. The relative stability of each of the ternary complexes was compared with that of corresponding binary complexes in terms of log K and log X values.     

Improved in‐solution trypsin digestion method for methanol–chloroform precipitated cellular proteomics sample

Methanol–chloroform based protein precipitation is an essential step in many liquid chromatography–tandem mass spectrometry‐based cellular proteomics applications. However, re‐solubilization of the total protein precipitate is difficult using regular in‐solution digestion protocol. Sodium deoxycholate is reported as an efficient surfactant for re‐solubilization of membrane fractions. In this study, we demonstrated an application combining methanol–chloroform based protein precipitations and deoxycholic acid assisted re‐solubilization of pellets to evaluate the improvement of protein identifications in mass spectrometry‐based bottom‐up proteomics. We evaluated the modified method using an equal amount of Raw 264.7 mouse macrophage cell lysate. Detailed in‐solution trypsin digestion studies were presented on methanol–chloroform precipitated samples with or without deoxycholic acid treatments and compared with popular sample digestion methods. A mass spectrometric analysis confirmed an 82% increase in protein identification in deoxycholic acid‐treated samples compared to other established methods. Furthermore, liquid chromatography–tandem mass spectrometry analysis of an equal amount of proteins from methanol–chloroform precipitated, and methanol–chloroform/deoxycholic acid‐treated macrophage cell lysate showed a 14% increase and 27% unique protein identifications. We believe this improved digestion method could be a complementary or alternative method for mammalian cell sample preparations where sodium dodecyl sulfate based lysis buffer is frequently used.