Study of gamma ray energy absorption and exposure buildup factors for ferrites by geometric progression fitting method

The gamma ray energy absorption and exposure buildup factors (EABF and EBF) were calculated for ferrites such as cobalt ferrite (CoFe₂O₄), zinc ferrite (ZnFe₂O₄), nickel ferrite (NiFe₂O₄) and magnesium ferrite (MgFe₂O₄) using five parametric geometric progression (G-P fitting) formula in the energy range 0.015–15.00?MeV up to the penetration depth 40 mean free path (mfp). The obtained data of absorption and exposure buildup factors have been studied as a function of incident photon energy and penetration depth. The obtained EABF and EBF data are useful for radiation dosimetry and radiation therapy.     

Simultaneous determination of metformin and glimepride in pharmaceutical dosage form by reverse-phase liquid chromatography

A simple, rapid, and precise reversed-phase liquid chromatographic method has been developed for the simultaneous determination of metformin in combination with glimepride. Under the developed conditions, good separation of the analytes was achieved in short analysis time. Several parameters affecting the separation of the analytes were studied, including pH and the concentration of SDS. The method is validated and shown to be linear in the range of 25 microg/mL to 150 microg/mL for metformin and 0.1 microg/mL to 0.6 microg/mL for glimepride. The method is applied for the analysis of these analytes in commercially available tablets.     

Synthesis and Characterization of Molecules Containing Thiazole and Oxazole Moieties and Study of ESIPT Phenomenon

Two novel ESIPT molecules, 2-[4-(1,3-benzothiazol-2-yl)naphtho[1,2-d][1,3]oxazol-2-yl]phenol 9a and 4-[4-(1,3-benzothiazol-2-yl)naphtho[1,2-d][1,3]oxazol-2-yl]benzene-1,3-diol 9b were synthesized by condensing 1-amino-3-(1,3-benzothiazol-2-yl)naphthalen-2-ol with 2-hydroxybenzoic acid and 2,4-dihydroxybenzoic acid respectively. The novel compounds were characterized by FT-IR, (1)H NMR, Mass spectral and elemental analysis. Effect of polarity on photo physical properties, absorption and emission were studied. Compounds showed single absorption and dual emission due to ESIPT phenomenon. The structural changes due to ESIPT phenomenon in terms of bond angle, bond distances and geometry were investigated by using Gaussian 03 software. These two novel ESIPT molecules are thermally stable up to 200?°C.     

Self-quenching of uranin: Instrument response function for color sensitive photo-detectors

Concentration is a key determining factor in the fluorescence properties of organic fluorophores. We studied self-quenching of disodium fluorescein (uranin) fluorescence in polyvinyl alcohol (PVA) thin films. The concentration dependent changes in brightness and anisotropy were followed by a lifetime decrease. We found that at a concentration of 0.54 M, the lifetime decreases to 7 ps. At a concentration of 0.18 M the lifetime was 10 ps with the relatively high quantum yield of 0.002. In these conditions the fluorescence intensity decay was homogeneous (well approximated by a single lifetime). We realized that such a sample was an ideal fluorescence lifetime standard for spectroscopy and microscopy, and therefore characterized instrument response functions for a time-domain technique. We show that self-quenched uranin enables measurements free of the color effect, making it a superior choice for a lifetime reference over scattered light.     

An efficient synthesis of benzodiazepinyl phosphonates as clostripain inhibitors via FeCl3 catalyzed four-component reaction

A novel one-pot route for the synthesis of benzodiazepinyl phosphonates (BDPs) has been achieved. FeCl(3) efficiently catalyzed four-component condensation of diamines, acetone and phosphites in the presence of molecular sieves to furnish BDPs as novel chemical entities with good yield. The synthesized BDPs have shown significant protease inhibition activity against clostripain, a disease model for gas gangrene, suggesting that these novel chemical entities could be further explored as cysteine protease inhibitors.     

Separation behavior of U(VI) and Th(IV) on a cation exchange column using 2,6-pyridine dicarboxylic acid as a complexing agent and its application for the rapid separation and determination of U and Th by ion chromatography

The retention behavior of U and Th as their 2,6-pyridine dicarboxylic acid (PDCA) complexes on a cation exchange column was investigated under low pH conditions. Based on the observed retention characteristics, an ion chromatographic method for the rapid separation of uranium and thorium in isocratic elution mode using 0.08 mM PDCA and 0.24 M KNO(3) in 0.22 M HNO(3) as the eluent was developed. Both uranium and thorium were eluted as their PDCA complexes within 2 min, whereas the transition and lanthanide metal cations were eluted as an unresolved broad peak after thorium. Under the optimized conditions both U and Th have no interference either from alkali and alkaline earth elements up to a concentration ratio of 1:500 or from other elements up to 1:100. The detection limits (LOD) of U and Th were calculated as 0.04 and 0.06 ppm, respectively (S/N=3). The precision in the measurement of peak area of 0.5 ppm of both U and Th was better than 5% and a linear calibration in the concentration range of 0.25-25 ppm of U and Th was obtained. The method was successfully applied to determine U and Th in effluent water samples.     

An Evaluation of Antimicrobial,Anticancer, Anti-Inflammatory and Antioxidant Activities of Silver Nanoparticles Synthesized from Leaf Extract of Madhuca longifolia Utilizing Quantitative and Qualitative Methods

In the current decade, nanoparticles are synthesized using solvents that are environmentally friendly. A number of nanoparticles have been synthesized at room temperature using water as a solvent, such as gold (Au) and silver (Ag) nanoparticles. As part of nanotechnology, nanoparticles are synthesized through biological processes. Biological methods are the preferred method for the synthesis of inorganic nanoparticles (AgNPs) as a result of their simple and non-hazardous nature. Nanoparticles of silver are used in a variety of applications, including catalysts, spectrally selective coatings for solar absorption, optical objectives, pharmaceutical constituents, and chemical and biological sensing. Antimicrobial agents are among the top uses of silver nanoparticles. In the current study, silver nanoparticles were biologically manufactured through Madhuca longifolia, and their antibacterial activity against pathogenic microorganisms, anticancer, anti-inflammatory, and antioxidant activities were assessed. UV-Vis spectroscopy, XRD (X-ray diffraction), transmission electron microscopy, Zeta Potential, and FTIR were used to characterize silver nanoparticles. The current work describes a cheap and environmentally friendly method to synthesize silver nanoparticles from silver nitrate solution by using plant crude extract as a reducing agent.     

Evaluation of a calix[4]-bis-crown-6 ionophore-based supported liquid membrane system for selective Cs transport from acidic solutions

Facilitated transport of Cs(I) from aqueous nitrate feed solutions to a receiver solution containing distilled water through a supported liquid membrane (SLM) containing calix[4]-bis-2,3-naphtho-crown-6 (CNC) in 0.45 μm PTFE (polytetrafluoroethylene) membranes was investigated. The carrier solution usually consisted of CNC dissolved in a mixture of 80% 2-nitrophenyl octyl ether and 20% n-dodecane. The transport rates were found to be influenced by the mobile carrier concentration, cesium concentration as well as the feed acidity. The extracted species conformed to a stoichiometry of 1:1 metal to ligand ratio suggesting the extraction of an organophilic mono-Cs-crown complex. Fission products obtained from an irradiated natural uranium target were found to be poorly transported while Cs-137 got significantly transported suggesting the possible application of the separation method for the removal of bulk Cs-137 from radioactive waste solutions. Durability/chemical stability of the membrane was remarkably good when tested over 20 days of continuous operation.     

Bianchi Type-III String Cosmological Models

Bianchi type III space time is considered in the presence of cosmic strings in Einstein’s general theory of relativity. Exact cosmological models are presented with the help of relation C=B ⁿ between metric coefficients C and B. Some physical properties of the model in each cases are discussed.     

Intramolecularly Double-Donor-Stabilized Stannylene and Its Coordination towards Ag(I) and Au(I) Centers

The intramolecularly double-donor-stabilized stannylene 1 has been synthesized from the salt-metathesis reaction between two equivalents of lithium pyridine ene-amide L1 and SnCl₂. Compound 1 exhibits dipolar behavior when reacted with B(C₆F₅)₃ leading to the zwitterionic compound 2 . The reaction of 1 with one equivalent and 0.5 equivalent of AgOTf (OTf=trifluoromethane sulfonate) result in the formation of a stannylene-AgOTf complex 3 and a homoleptic distannylene-silver ionic complex 4 , respectively. Analogous to complex 4 , the gold(I) complex 5 has been synthesized from the reaction between two equivalents of 1 and 0.5 equivalent of AuCl.SMe₂/Me₃SiOTf. Complex 5 is the first example of homoleptic stannylene-Au(I) ionic complex among the very scarce reports on stannylene-gold(I) coordination complexes. All compounds have been structurally characterized using single crystal X-ray crystallography. Solution-state characterization have been performed using multinuclear NMR techniques. Detailed DFT calculations on the optimized geometries 1 o , 3 o – 5 o reveal the change in sp- hybridization on the pyramidal Sn(II) center upon metal coordination and their bonding overlaps.