排序方式: 共有68条查询结果,搜索用时 15 毫秒
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We report a biosensing method that is based on magnetically immobilized functional liposomes. The vesicles encapsulate magnetic nanoparticles (MNP) and enzymatic sensing reagents. Magnetic attraction between MNP and external magnets first immobilizes liposomes onto the surface of a coverglass. With the assistance from α-hemolysin (aHL), translocations of analytes through a lipid membrane trigger intravesicular enzymatic reactions. After 90 s incubation, the product from the sensing reactions, resorufin, was probed by laser-induced fluorescence. Detection of two analytes, glucose and ethanol, was demonstrated using two types of functional vesicles. The effects of MNP-containing vesicles and biotinylated vesicles on aHL's translocations of analytes were also compared. Unlike biotinylated lipids, MNP facilitate immobilization of liposomes without compromising the integrity of membrane and pore-forming activity of aHL. 相似文献
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V. P. Dhamgaye G. S. Lodha B. Gowri Sankar C. Kant 《Journal of synchrotron radiation》2014,21(1):259-263
The X‐ray lithography beamline on Indus‐2 is now operational, with two modes of operation. With a pair of X‐ray mirrors it is possible to tune the energy spectrum between 1 and 20 keV with a controlled spectral bandwidth. In its `no optics' mode, hard X‐rays up to 40 keV are available. Features and performance of the beamline are presented along with some example structures. Structures fabricated include honeycomb structures in PMMA using a stainless steel stencil mask and a compound refractive X‐ray lens using a polyimide–gold mask in SU‐8. 相似文献
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S. Sreehari Sastry K. Mallika B. Gowri Sankara Rao Sie Tiong Ha S. Lakshminarayana 《Phase Transitions》2013,86(8):735-749
A novel approach is proposed to investigate the phase transitions of cholesteric liquid crystals using the Legendre moments. The textures of cholesteric liquid crystals (cholesteryl butyrate, cholesteryl n-valerate, cholesteryl decanoate, and cholesteryl myristate) are captured as a function of temperature using high-resolution camera attached to the arthroscopic mode of polarizing optical microscope with hot stage. A recurrence formula is used to compute the Legendre moments of the liquid crystal textures based on the Legendre polynomial using MATLAB software. The abrupt change in the values of Legendre moments as a function of temperature gives the phase transitions of liquid crystals. The investigated transition temperatures of cholesteric liquid crystals are compared with other techniques. 相似文献
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Ponnapalli Mangala Gowri Sri Vedavyasa Srirangaraja Radhakrishnan Bhattar Poreddy Guruva Reddy Yerraballi Rakesh Shaik Jeelani Basha Akella Venkata Subrahmanya Sarma Janaswamy Madhusudana Rao 《Helvetica chimica acta》2009,92(7):1419-1427
An extensive study of metabolites present in Excoecaria agallocha Linn . led to the isolation of three new ent‐labdane‐type diterpenoids, named agallochaexcoerins A–C ( 1 – 3 ), besides three known compounds. The skeleton present in compound 1 is rather unusual, containing of a seven‐membered lactone. The structures were elucidated on the basis of spectroscopic studies and comparison with known related compounds. The isolated compounds 1 – 6 were not active against Raw 264.7 (macrophage‐like), K 562 (leukemia), and COLO 205 (colon) human carcinoma cell lines. 相似文献
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Gowri Ramachandran George Simon Yibing Cheng Trevor A. Smith Liming Dai 《Journal of fluorescence》2003,13(5):427-436
The effects of metal salts (NaCl, CaCl2·2H2O, EuCl3·6H2O and Eu(OAc)3) on the steady state and time resolved fluorescence behaviour of poly(para phenylene vinylene) oligomers containing benzo-15-crown-5 ether units (CE-OPV) have been investigated. The presence of EuCl3 causes a significant (8–9 fold) increase in the fluorescence emission intensity of the OPV segments, as compared to pure CE-OPV, in 99:1 methanol/chloroform solution and a small (9 nm) red shift in the emission maximum. The presence of Na+ or Ca2+ results in less marked increases in fluorescence intensity compared to Eu3+. In the presence of Eu3+ and Na+, the fluorescence intensity increases approximately linearly with metal ion concentration up to a metal ion/CE-OPV molar ratio of 10. The emission enhancement is not related to a simple 1:1 (CE-OPV:metal ion) complex formation process. In contrast, in acetonitrile, CE-OPV shows complex fluorescence quenching behaviour as a function of EuCl3 concentration. This solvent dependence suggests that the emission changes with metal concentration are related to the formation of charge-transferred complexes. The marked changes in fluorescence quantum yield of the PPV backbone due to complexation with metal ions makes CE-OPV a sensitive fluorescent probe for metal ions, or may be exploited for improving the quantum yield of PPV-based devices. 相似文献
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Revuru Venkateswarlu Chakicherla Kamakshi Syed G.A. Moinuddin Mangala P. Gowri Robert S. Ward Andrew Pelter Simon J. Coles 《Tetrahedron》2005,61(37):8956-8961
The synthesis of gmelanone 2 by a pinacol-type rearrangement of arboreol 1 supports its biogenesis and confirms its relative and absolute configuration. The further transformation of gmelanone oxime 12 into the dihydropyranone oxime 13 supports the intermediacy of gmelanone like intermediates in the rearrangements of furofuran lignans to pyran derivatives. In contrast, acid-catalysed rearrangement of wodeshiol 7 affords the dihydropyranone 8. 相似文献
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A single crystal of Pyridine-1-ium-2-carboxylatehydrogenbromide (PHBr) was grown using the Slow Evaporation Solution Technique. Using Single Crystal X-Ray Diffraction analysis, the crystal lattice characteristics and molecular structure of the grown crystal of PHBr were found and it corresponds to the Triclinic crystal system with space group Pī. Intra and intermolecular interactions were visualized using Hirshfeld surface analysis. The theoretical calculation conducted by Density Functional Theory (DFT) and it is well agreed with the experimental results. The Molecular optimized geometry, FT-IR and HOMO-LUMO energy gap were computed using the B3LYP level of theory with a 6-31 + G (d,p) basis set. The FT-IR spectrum studies are given here to look at the modes of vibration of numerous functional groups found in the PHBr crystal. The measurements of UV–visible NIR transmittance show that the crystal has a high transmittance over the whole visible spectrum. The Z-scan approach is used to perform third-order nonlinear optical (NLO) investigations on a PHBr crystal and optical properties such as linear and nonlinear refractive index are computed. 相似文献
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