Thermoluminescence studies of UV-irradiated Y2O3:Eu3+ doped phosphor

The present paper reports thermoluminescence (TL) glow curves of Eu³⁺-doped Y₂O₃ phosphor with different ultraviolet (UV) exposure times. The glow peak shows second-order kinetics of Eu³⁺-doped Y₂O₃, and corresponding kinetic parameters were evaluated using the peak shape method. Calculations of trap depth were carried out using different methods. The kinetics order, activation energy, and frequency factor were calculated. The recorded glow curve shifts towards higher intensity with longer UV exposure. The heating rate used for recording TL was 3.0 °C s^?1. Particle size and structure were verified by X-ray diffraction (XRD) pattern and morphology by scanning electron microscopy (SEM) imaging.     

ProSTRIP: A method to find similar structural repeats in three-dimensional protein structures

The occurrence of similar structural repeats in a protein structure has evolved through gene duplication. These repeats act as a structural building block and form more than one compact structural and functional unit called a repeat domain. The protein families comprising similar structural repeats are mainly involved in protein–protein interactions as well as binding to other ligand molecules. The identification of internal sequence repeats in the primary structure is not sufficient for the analysis of structural repeats. Thus, a new method called ProSTRIP has been developed using dynamic programming to find the similar structural repeats in a three-dimensional protein structure. The detection of these repeats is made by calculating the protein backbone Cα angles. An internet computing server is also created by implementing this method and enables graphical visualization of the results. It can be freely accessed at http://cluster.physics.iisc.ernet.in/prostrip/.     

Microwave mediated synthesis of spiro-(indoline-isoxazolidines): mechanistic study and biological activity evaluation

Regioisomeric spiro-(indoline-isoxazolidines) have been synthesized in moderate yields by the cycloaddition reaction between ethyl (3-indolylidene)acetate and various substituted α,N-diphenylnitrones, using environmentally benign microwave technology. A novel concerted reaction mechanism is described that explains the preferential formation of the regioisomeric spiro-(indoline-isoxazolidine) analogs 6 over 5. These compounds were screened for anti-mycobacterial and anti-invasive activities against tumor cells.     

Design, synthesis and biological evaluation of choline based SPECT imaging agent: Ga(III)-DO3A-EA-Choline

The enhanced choline uptake and phosphorylation in tumor cells has motivated the development of radiolabeled choline derivatives as diagnostic markers for imaging cell membrane proliferation and noninvasive detection of prostate, brain and breast tumors. In the present work, we report a facile strategy for the synthesis of choline functionalized macrocyclic chelating agent (DO3A-EA-choline) and its radiocomplexation with (67)Ga for potential tumor imaging applications. The synthesis of the desired compound featured quaternization of N,N-dimethylaminoethanol with 1,2-dibromoethane followed by subsequent alkylation with trisubstituted cyclen (DO3A). All intermediates and final compounds have been fully characterized by spectroscopic techniques, namely, (1)H, (13)C NMR and mass spectroscopy. The compound has been successively labeled with (67)Ga-citrate in ammonium acetate buffer (pH 6.5) at 80 °C. MTT assays have been performed on the HEK cell line to determine the cytotoxicity of the compound. Cell uptake studies carried out on the U-87 MG cell line exhibited saturable binding of the radioconjugate in picomolar range with a K(d) value of 0.528 pM. The in vivo biodistribution and blood kinetics studies exhibited rapid clearance of the radiolabeled complex and excretion through the renal and hepatobiliary route. The present studies demonstrate the potential applications of (67)Ga-DO3A-EA-choline as a radiopharmaceutical for molecular imaging using ((67/68)Ga) SPECT and PET modalities.     

Growth and synthesis of Sr<Subscript>3</Subscript>MgSi<Subscript>2</Subscript>O<Subscript>8</Subscript>:Dy<Superscript>3+</Superscript> nanorod arrays by a solid state reaction method

Sr₃MgSi₂O₈:Dy³⁺ Nano-rods were synthesized by using solid state reaction method. The structural properties, morphology and band structure properties of the phosphor was studied. The structural properties were examined by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. Bonding behaviour of the phosphor was also determined by recording the FTIR spectra of the phosphor. Band structure i.e. band gap of the phosphor was determined by recording the absorption spectrum. The absorption spectrum was recorded for the sample and the band gap was determined by using Tauc plot. Band gap of the phosphor was found around 5.4 eV.     

Application of voltammetric methods for the analysis of gold and other transition metals in quartzite rock

Simple, rapid and accurate voltammetric methods viz. DCP, DPP and DPASV have been presented for the trace determination of gold and other transition metals in quartzite rock sample. The analysis has been performed using 0.1 M(NH4)2 tartrate, 0.1 M NaClO4 and 1 M NaOH as supporting electrolyte with 0.001% gelatin as maximum suppressor. The results show the presence of CuII(10.70), CoII(4.72), FeIII(66.96), AuIII(0.066), ZnII(1.68) and CdII(0.62) mg x g(-1) metal ions from the sample. Gold produced a well defined wave/peak with E1,2/Ep = -0.61 V/-0.64 V vs SCE, in 1 M NaOH supporting electrolyte. The quantitative analysis of metal inos was carried out by the method of standard addition. Statistical treatment of the observed voltammetric data reveals high accuracy and good precision of determination. The observed voltammetric results are comparable with those obtained using AAS method.     

Antihyperglycemic agents from Ammannia multiflora

The serial chromatographic separation of chloroform and n-butanol fractions of Ammannia multiflora resulted in the isolation and characterization of 4-hydroxy-alpha-tetralone (1) and 3,3'-(2R,5R)-tetrahydrofuran-2,5-diyldiphenol (ammaniol, 2). Compound 1 was chemically modified into six semi-synthetic acyl and aryl derivatives (1A - 1F). The isolated compounds 1 and 2 along with semi-synthetic derivatives 1A - 1F were evaluated for in vitro antihyperglycemic activity employing 2-deoxyglucose uptake by L-6 rat muscle cell lines. The results indicated that both the isolates, as well as derivatives (1A - 1F), have the property to stimulate glucose uptake. Ammaniol (2) increased glucose uptake significantly (64.8%), while one of the aryl derivatives of 1, 4-O-(3,4,5-trimethoxybenzoyl)-alpha-tetralone (1D), showed potent antihyperglycemic activity and increased glucose uptake by 94.6%, even more than rosiglitazone (88.8%). Further, since 1D possesses better antihyperglycemic activity than rosiglitazone (standard), this might be a new safer antidiabetic drug of herbal origin.     

Characterization and luminescence properties of Gd2O3 phosphor

Gd₂O₃ phosphor was synthesized by combustion synthesis using gadolinium nitrate hexahydrate as precursor and urea as fuel. Structural and surface morphology were studied by X-ray diffraction, transmission electron microscopy (TEM), and scanning electron microscopy (SEM). Chemical composition analysis of the phosphor was performed by Fourier-transform infrared spectroscopy, and tts optical properties were characterized by use of photoluminescence (PL) and thermoluminescence (TL) techniques. In PL spectra, feeble emission at 490 nm (blue) and intense emission at approximately 545 nm (green) are observed after excitation at 300 nm. TL measurement was performed on the Gd₂O₃ phosphor by irradiating it with γ-rays (1 kGy). A well resolved glow peak at 226.4 °C was observed. Kinetic data were estimated from the TL glow curve by use of Chen’s peak-shape method; the results are discussed in detail. The average particle size of the Gd₂O₃ phosphor was 41 nm; a monoclinic phase was formed at a firing temperature of 500 °C. This was in agreement with SEM and TEM results.     

β-Sitosterol-D-Glucopyranoside Mimics Estrogenic Properties and Stimulates Glucose Utilization in Skeletal Muscle Cells

Estrogenic molecules have been reported to regulate glucose homeostasis and may be beneficial for diabetes management. Here, we investigated the estrogenic effect of β-sitosterol-3-O-D-glucopyranoside (BSD), isolated from the fruits of Cupressus sempervirens and monitored its ability to regulate glucose utilization in skeletal muscle cells. BSD stimulated ERE-mediated luciferase activity in both ERα and ERβ-ERE luc expression system with greater response through ERβ in HEK-293T cells, and induced the expression of estrogen-regulated genes in estrogen responsive MCF-7 cells. In silico docking and molecular interaction studies revealed the affinity and interaction of BSD with ERβ through hydrophobic interaction and hydrogen bond pairing. Furthermore, prolonged exposure of L6-GLUT4myc myotubes to BSD raised the glucose uptake under basal conditions without affecting the insulin-stimulated glucose uptake, the effect associated with enhanced translocation of GLUT4 to the cell periphery. The BSD-mediated biological response to increase GLUT4 translocation was obliterated by PI-3-K inhibitor wortmannin, and BSD significantly increased the phosphorylation of AKT (Ser-473). Moreover, BSD-induced GLUT4 translocation was prevented in the presence of fulvestrant. Our findings reveal the estrogenic activity of BSD to stimulate glucose utilization in skeletal muscle cells via PI-3K/AKT-dependent mechanism.