Role of Annealing Atmosphere on Structure,Dielectric and Magnetic Properties of La2CoMnO6 and La2MgMnO6

Polycrystalline samples of La₂MMnO₆ (M = Co and Mg) were prepared by a combined gel‐combustion and high temperature reaction method. The samples were annealed in different oxygen partial pressure (p_O2) and characterized by powder XRD, SQUID magnetometry, ac impedance spectroscopy, and electron paramagnetic resonance techniques. Monoclinic (P2₁/n) and rhombohedral (R$\bar{3}$ ) lattices were observed for La₂CoMnO₆ and La₂MgMnO₆, respectively. On annealing in inert atmosphere, La₂MgMnO₆ partially converted to monoclinic La₂CoMnO₆ type structure, whereas no structural change was observed in La₂CoMnO₆. Dielectric studies of La₂CoMnO₆ indicated relaxor like behavior with polaronic conduction, which systematically decreased with the increase in p_O2 of the annealing atmosphere. Magnetic studies indicated multiple ferromagnetic phase transitions in La₂CoMnO₆ and a spin‐glass like phase transition in La₂MgMnO₆. The fraction of ferromagnetic phases of La₂CoMnO₆ was significantly dependent on the annealing environments. The variations of magnetic and dielectric properties of samples were related to the fluctuation of oxidation state of transition metal ions and oxygen vacancies in the samples.     

Behavior of collagen films in presence of structure modifiers at solid–liquid interface

Films of soluble collagen extracted from rat‐tail tendon were studied at the solid–solution interface, and the surface energy of the films was evaluated. The films transferred onto solid substrates using the Langmuir–Blodgett film (LB film) technique were characterized using Fourier transform IR attenuated total reflectance spectroscopy and atomic force microscopy. The properties of the protein in contact with different structure modifiers like basic chromium sulfate (BCS) and formaldehyde (HCHO) were analyzed for the effect of various tanning agents on the protein structure. The thermal properties of the films were studied using differential scanning calorimetry. The results show that the film of collagen treated with BCS exhibits an increase in the peak temperature and enthalpy changes compared to the pure collagen as well as the protein with HCHO. These differences are attributed to the changes in the crosslinks arising from both coordinate–covalent and covalent interactions, respectively. The atomic force micrographs showed an increase in order for the collagen film with BCS compared to the HCHO treated analogue. A similar trend is seen in the surface energy parameters of the protein films on solid surfaces on reacting with BCS and HCHO, suggesting a molecular level ordering process in collagen assemblies. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 3859–3865, 2004     

On the existence of canted spins in Mg-Zn system

The variation of magnetization as a function of Zn concentration in the Mg-Zn system is measured using a high-field loop tracer at liquid nitrogen temperature. The XRD studies show that the lattice parameter increases linearly with increase in the zinc content. The magnetization is found to increase with the zinc concentration, reaches a maximum atx=0.2 and thereafter falls to zero for non magnetic zinc ferrite, which is the behaviour similar to other zinc containing ferrites. The variation of magnetization as a function of zinc content suggests the existence of a canted type of spin arrangement in this system. The cation distribution is suggested.The authers are thankful to Professor R. N. Patil for encouragement     

Microwave absorption studies of MgB2 superconductor

Microwave absorption studies have been carried out on MgB₂ superconductor using a standard X-band EPR spectrometer. The modulated low-field microwave absorption signals recorded for polycrystalline (grain size ∼ 10 μm) samples suggested the absence of weak-link character. The field dependent direct microwave absorption has been found to obey a ✓H dependence with two different slopes, which indicated a transition from strongly pinned lattice to flux flow regime.     

Rhodamine Based Turn-On Sensors for Ni<Superscript>2+</Superscript> and Cr<Superscript>3+</Superscript> in Organic Media: Detecting CN<Superscript>−</Superscript> via the Metal Displacement Approach

Two novel sensors bearing rhodamine B and quinoline units have been synthesized. One of these, 1, allows sensitive and selective detection of Ni²⁺ and Cr³⁺ by forming non-fluorescent (1-Ni²⁺) and fluorescent (1-Cr³⁺) complexes respectively. Both metals trigger the formation of highly colored ring-open spirolactam. These form excellent probes for CN^? which quenches the fluorescence of the 1-Cr³⁺ complex by extracting the Cr³⁺. Both Cr³⁺ and Cu²⁺ gave color changes with 2, but they are easily identified separately via the large fluorescence enhancement that occurs only with Cr³⁺.     

Corrosion,wear, and cell culture studies of oxygen ion implanted Ni–Ti alloy

To increase the biocompatibility of nickel–titanium (Ni–Ti) alloy substrates, oxygen ions have been implanted by the plasma immersion ion implantation (PIII–O) technique at low temperature without affecting the substrate properties. The implanted Ni–Ti surface is characterized for microhardness and composition. Energy‐dispersive spectroscopy and X‐ray photoelectron spectroscopy investigations show the replacement of native oxide on the alloy by a compact oxide during the implantation process. The corrosion behaviors of untreated substrate and PIII–O samples are investigated using potentiodynamic polarization and electrochemical impedance spectroscopy in simulated body fluid (Hanks' solution). Polarization and electrochemical impedance spectroscopy studies reveal nearly ideal capacitor behavior with better passivation characteristics for the oxygen‐implanted substrate. Sliding wear studies reveal lower friction of coefficient for the implanted layers as compared with the substrate. The bare and surface modified Ni–Ti alloy samples are evaluated for biocompatibility using osteoblast‐like cells (MG‐63). Cellular behavior in terms of cell morphology along with the viability and proliferations is evaluated by using scanning electron microscopy and in vitro cell culture assay, respectively. The results clearly show that oxygen implantation by PIII–O provides a better compatible surface for cell attachment and growth. The modified surface exhibits a higher percentage of cell viability demonstrating the enhanced biocompatibility of the oxygen‐implanted surface compared with bare Ni–Ti alloy. Copyright © 2017 John Wiley & Sons, Ltd.     

Synthesis,crystal structure and molecular docking studies of novel 2-(4-(4-substitutedphenylsulfonyl)piperazin-1-yl)quinolone-3-carbaldehyde derivatives

The present work reports the synthesis of novel 2-(4-(4-substitutedphenylsulfonyl) piperazin-1-yl) quinolone-3-carbaldehyde derivatives, namely, 2-(4-tosylpiperazin-1-yl)quinoline-3-carbaldehyde (4a), 2-(4-(4-nitrophenylsulfonyl)piperazin-1-yl)quinoline-3-carbaldehyde (4b) and 2-(4-(4-tert-butylphenylsulfonyl) piperazin-1-yl)quinoline-3-carbaldehyde (4c). These compounds have been characterized by FT-IR, ¹H-NMR, ¹³C-NMR and LCMS. Further, the structures of compounds 4b and 4c have been elucidated by single crystal X-ray diffraction studies. The asymmetric unit of 4b contains two molecules (A and B) and that of 4c contains one. The piperazine ring in both the molecules 4b and 4c has chair conformation and the aldehyde group is twisted with respect to the quinoline group, respectively, by 13.3 (3)°, 18.2 (3)° and 11.2 (3)° in Molecule A & B of 4b and 4c due to the bulky piperazinyl group present in the ortho position. The crystal structures of both features interactions of the type C-H…O, C-H…π_aryl and π_aryl… π_aryl, leading to a three-dimensional (3D) supramolecular architecture in 4b and a one-dimensional (1D) architecture in 4c. The various intermolecular interactions exhibited in 4b and 4c are well supported by Hirshfeld surface and fingerprint plots analysis. Further, the three compounds were evaluated for their in-silico antimicrobial activity. In-silico molecular docking studies were carried out in order to know the binding modes of the synthesized compounds with DNA Gyrase A and N-myristoyltranferase as target proteins for antibacterial and antifungal docking studies, respectively.     

High-Performance Thin-Layer Chromatography and Indirect TLC—HRMS-Based Determination of 20-Hydroxyecdysone in Sesuvium portulacastrum

JPC – Journal of Planar Chromatography – Modern TLC - 20-Hydroxyecdysone (20E), an imperative phytoecdysteroid, regulates several biochemical and physiological processes during the...     

Synthesis,Characterization, and DGAT1 Inhibition of New 5‐Piperazinethiazole and 5‐Piperidinethiazole Analogs

In this study, a novel series of 5‐piperazinethiazole 2,2‐dimethylbutanoic acid and 5‐piperidinethiazole 2,2‐dimethylbutanoic acid derivatives have been synthesized. Structures of the newly synthesized compounds have been elucidated using ¹H‐NMR, ¹³C‐NMR, high‐resolution mass spectroscopy, and high‐performance liquid chromatographic analysis. The synthesized derivatives have been evaluated in vitro for their ability to inhibit the enzyme diacylglycerol acyltransferase 1 responsible for triglyceride biosynthesis.