Photoluminescence and thermoluminescence studies of Mg2SiO4:Eu3+ nano phosphor

Nanoparticles of Eu3+ doped Mg2SiO4 are prepared using low temperature solution combustion technique with metal nitrate as precursor and urea as fuel. The synthesized samples are calcined at 800 degrees C for 3 h. The Powder X-ray diffraction (PXRD) patterns of the sample reveled orthorhombic structure with alpha-phase. The crystallite size using Scherer's formula is found to be in the range 50-60 nm. The effect of Eu3+ on the luminescence characteristics of Mg2SiO4 is studied and the results are presented here. These phosphors exhibit bright red color upon excitation by 256 nm light and showed the characteristic emission of the Eu3+ ions. The electronic transition corresponding to D-5(0) -> F-7(2) of Eu3+ ions (612 nm) is stronger than the magnetic dipole transition corresponding to D-5(0) -> F-7(1) of Eu3+ ions (590 nm). Thermoluminescence (TL) characteristics of gamma-rayed Mg2SiO4: Eu3+ phosphors are studied. Two prominent and well-resolved TL glows with peaks at 202 degrees C and 345 degrees C besides a shoulder with peak at similar to 240 degrees C are observed. The trapping parameters-activation energy (E), order of kinetics (b) and frequency factor (s) are calculated using glow curve shape method and the results obtained are discussed. (C) 2011 Elsevier B.V. All rights reserved

Ionoluminescence and photoluminescence studies of Ag8+ ion irradiated kyanite

Ionoluminescence (IL) of kyanite single crystals bombarded with 100 MeV swift Ag8+ ions with fluences in the range 1.87–7.5×1011 ions/cm2 has been studied. A pair of sharp IL peaks at ∼689 and 706 nm along with broad emission in the region 710–800 nm are recorded in both crystalline and pelletized samples. Similar results are recorded in Photoluminescence (PL) of pelletized kyanite bombarded with same ions and energy with fluences in the range 1×1011–5×1013 ions/cm2 with an excitation of 442 nm laser beam. The characteristic pair of sharp emission peaks at 689 and 706 nm in both IL and PL is attributed to luminescence centers activated by Fe2+ and Fe3+ ions. The reduction in IL and PL bands intensity with increase of ion fluence might be attributed to degradation of Si–O (2ν3) bonds, present on the surface of the sample

Damage creation in swift heavy ion-irradiated calcite single crystals: Raman and Infrared study

Raman and Infrared studies were carried out on pristine and 100 MeV Ag8+ ion irradiated calcite single crystals in the fluence range 1 à 1011 to 1 à 1013 ions/cm2. Raman and Infrared modes were assigned according to factor theory analysis. It is observed that the intensities of the Raman and infrared bands decrease with increase of ion fluence. The decrease of these bands is attributed to breakage of carbonate ions and other details are discussed. © 2008 Elsevier B.V. All rights reserved

100MeV Si8+ Ion Induced Luminescence and Thermoluminescence of Nanocrystalline Mg2SiO4:Eu3+

Nanoparticles of Mg2SiO4:Eu3+ have been prepared by the solution combustion technique and the grain size estimated by PXRD is found to be in the range 40-50 nm. Ionoluminescence (IL) studies of Mg2SiO4:Eu3+ pellets bombarded with 100 MeV Si8+ ions with fluences in the range 1.124-22.48×1012 ions cm−2 are carried out at IUAC, New Delhi, India. Five prominent IL bands with peaks at 580 nm, 590 nm, 612 nm, 655 nm and 705 nm are recorded. These characteristic emissions are attributed to the luminescence centers activated by Eu3+ cations. It is found that IL intensity decreases rapidly in the beginning. Later on, the intensity decreases slowly with further increase of ion fluence. The reduction in the ionoluminescence intensity with increase of ion fluence might be attributed to degradation of Si-O (ν3) and Si-O (2ν3) bonds present on the surface of the sample. The red emission with peak at 612 nm is due to characteristic emission of 5D0→7F2 of the Eu3+ cations. Thermoluminescence (TL) studies of Mg2SiO4:Eu3+ pellets bombarded with 100 MeV Si8+ cations with fluences in the range 5×1011 ions cm−2 to 5×1013 ions cm−2 are made at RT. Two prominent and well resolved TL glows with peaks at ∼220 °C and ∼370 °C are observed. It is observed that TL intensity increases with increase of ion fluence. This might be due to creation of new traps during swift heavy ion irradiation.

Crystal and molecular docking studies of 3-​[Bis-​(2-​hydroxy-​4,​4-​dimethyl-​6-​oxo-​cyclohex-​1-​enyl)​-​methyl]​benzonitrile with focal adhesion kinase inhibitors

In the present study crystal structure of 3-​[Bis-​(2-​hydroxy-​4,​4-​dimethyl-​6-​oxo-​cyclohex-​1-​enyl)​-​methyl]​benzonitrile was detd. using single crystal X-​ray diffraction. Further the structural features was extrapolated to mol. docking studies with focal adhesion kinase (FAK) domain using Autodock to study its anticancerous property. The compd. exhibited considerable bacterial inhibition of lower to moderate concns. We conclude that these derivs. can be used in medicine and have enormous potential as pharmaceutical agents due to their biol. activities. The above titled receptor gain functional and structural insights into their mechanism of inhibition and explore its potential as an anticancer agent

Crystal and Molecular Docking Studies of 3-[ Bis-(2-Hydroxy-4,4-Dimethyl-6-Oxo-Cyclohex-1-Enyl)-Methyl]Benzonitrilewith Focal Adhesion Kinase Inhibitors

In the present study crystal structure of 3-[Bis-(2-hydroxy-4,4-dimethyl-6-oxo-cyclohex-1-enyl)-methyl]benzonitrile was determined using single crystal X-ray diffraction. Further the structural features was extrapolated to molecular docking studies with focal adhesion kinase (FAK) domain using Autodock to study its anticancerous property. The compound exhibited considerable bacterial inhibition of lower to moderate concentrations. We conclude that these derivatives can be used in medicine and have enormous potential as pharmaceutical agents due to their biological activities. The above titled receptor gain functional and structural insights into their mechanism of inhibition and explore its potential as an anticancer agent

In silico docking analysis of piperine with cyclooxygenases

The structure of 1-[5-(1,3-benzodioxol- 5-yl)-1-oxo-2,4- pentadienyl]piperidine (Piperine), C17H19O3N, a versatile bioactive molecule has been redetermined at 100(2) K by X-ray crystallography to explore their potential utilization in inhibition of prostaglandin release. The crystal structure is stabilized by weak nonclassical intermolecular C-H…O hydrogen bonds and also intermolecular C-H…π interactions. The crystallographic coordinates of the compound were extrapolated to docking studies to elucidate the action of piperine against the enzymes, cyclooxygenases (COX-1 and COX-2) involved in biosynthesis of prostaglandin release. Using AutoDock suite, piperine was docked at the binding site of COX-1 and COX-2 enzyme and a strong affinity (-9.06kcal/mol, Ki =227.73nM and -8.77kcal/mol, Ki = 375.62nM, respectively) was formed by Hydrogen bonds and hydrophobic interactions. These results suggest that piperine can be a promising lead for the development of COX family inhibitors

Ion beam-induced luminescence and photoluminescence of 100 MeV Si8+ ion irradiated kyanite single crystals

Ionoluminescence (IL) of kyanite single crystals during 100 MeV Si8+ ion irradiation has been studied in the fluence range 1.87-7.50Ã1011 ions/cm2. Photoluminescence (PL) of similar dimensional crystals was recorded with same ions and energy in the fluence range 1Ã1011-5Ã1013 ions/cm2 with an excitation of 442 nm He-Cd laser beam. A sharp IL and broad PL peaks at â¼689 and 706 nm were recorded. This is attributed to luminescence centers activated by Fe2+ and Fe3+ ions. It is observed that up to a given fluence, the IL and PL peak intensities increase with increase of Si8+ ion fluence. The stability of the chemical species was studied on with and without irradiated samples by means of FT-IR spectroscopy. The results confirm that the O-Si-H type bonds covering on the surface of the sample. This layer might be acting as a protective layer and thereby reducing the number of non-radiative recombination centers. © 2008 Elsevier Ltd. All rights reserved