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Red Dye (red + dye)
Selected AbstractsDonor,Acceptor Systems: Energy Transfer from CdS Quantum Dots/Rods to Nile Red DyeCHEMPHYSCHEM, Issue 14 2008Suparna Sadhu Abstract We demonstrate strong evidence of shape-dependent efficient resonance energy transfer between CdS quantum dots (QDs) and quantum rods (QRs) (donor) to Nile Red dye (acceptor). We also report a simple solution-based method for the preparation of high quality CdS QDs and CdS QRs at relatively low temperature. The observed quenching of PL intensities are 78.8,% and 63.8,% for CdS QDs and QRs, respectively in the presence of Nile Red dye. The calculated energy-transfer efficiencies are 45,% and 19,% from QDs and QRs to dyes, respectively. The energy transfer varies with changing the shape of the nanoparticles. The estimated Förster distances (R0) are 37.8 and 33.8 Å for CdS QDs and QRs, respectively. In the present study, the estimated distances (r) between one donor and one acceptor are 39.1 and 43.1 Å for QDs and QRs, respectively, using the efficiency of Förster resonance energy transfer (FRET) which depends on the inverse sixth power of the distance of separations between one nanocrystal and one dye molecule. Considering single donor and multiple acceptors interactions, the calculated average distances (rn) between the donor and acceptor are 47.7 and 53.9 Å for QD's and QR's, respectively. The steady-state and time-resolved spectroscopic analysis of nanoassemblies confirm the formation of one donor and multiple acceptors. [source] Application of Congo Red agar for detection of Streptococcus dysgalactiae isolated from diseased fishJOURNAL OF APPLIED ICHTHYOLOGY, Issue 4 2009M. Abdelsalam Summary The strong clinical similarity between Lancefield group C Streptococcus dysgalactiae subsp. dysgalactiae (GCSD) and Lactococcus garvieae infections, characterized by development of necrotic lesions in the caudal peduncle of infected fish, has hindered differentiation of these two strains, making rapid and accurate diagnosis of diseased fish in fish farms difficult. GCSD from diseased fish were presumptively identified and isolated using Todd-Hewitt agar containing 30 ,g ml,1 of Congo Red dye (TH-CR). TH-CR agar was also used to detect and presumptively identify the GCSD obtained from artificially or naturally infected fish. Orange GCSD colonies distinct from the L. garvieae colonies were observed on the TH-CR agar; thus, TH-CR agar can be used to detect and identify GCSD isolated from infected fish. [source] Light propagation and scattering in porous silicon nanocomposite waveguidesPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 8 2005P. Pirasteh Abstract Planar waveguides have been achieved from oxidised porous silicon layers (OPS) which have been impregnated by solvents, Congo Red (CR) dye and poly(p-phenylene vinylene) (PPV) polymer. Optical loss has been investigated by a simple technique based on surface optical scattering measurements. Optical loss has been studied as a function of the wavelength, impregnation type and CR concentration. The main sources of attenuation, such as absorption, scattering from interface roughness, scattering from nano- crystallites and modification of the refractive indexes after filling are discussed. Optical loss measured at 0.633 µm is about 1.8 dB/cm for the OPS waveguides The optical loss decreases with wavelength. Otherwise, the optical loss increases with the concentration of Congo Red dye which is absorbent at this wavelength. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Donor,Acceptor Systems: Energy Transfer from CdS Quantum Dots/Rods to Nile Red DyeCHEMPHYSCHEM, Issue 14 2008Suparna Sadhu Abstract We demonstrate strong evidence of shape-dependent efficient resonance energy transfer between CdS quantum dots (QDs) and quantum rods (QRs) (donor) to Nile Red dye (acceptor). We also report a simple solution-based method for the preparation of high quality CdS QDs and CdS QRs at relatively low temperature. The observed quenching of PL intensities are 78.8,% and 63.8,% for CdS QDs and QRs, respectively in the presence of Nile Red dye. The calculated energy-transfer efficiencies are 45,% and 19,% from QDs and QRs to dyes, respectively. The energy transfer varies with changing the shape of the nanoparticles. The estimated Förster distances (R0) are 37.8 and 33.8 Å for CdS QDs and QRs, respectively. In the present study, the estimated distances (r) between one donor and one acceptor are 39.1 and 43.1 Å for QDs and QRs, respectively, using the efficiency of Förster resonance energy transfer (FRET) which depends on the inverse sixth power of the distance of separations between one nanocrystal and one dye molecule. Considering single donor and multiple acceptors interactions, the calculated average distances (rn) between the donor and acceptor are 47.7 and 53.9 Å for QD's and QR's, respectively. The steady-state and time-resolved spectroscopic analysis of nanoassemblies confirm the formation of one donor and multiple acceptors. [source] An assay system for the detection of phospholipase C activityEUROPEAN JOURNAL OF LIPID SCIENCE AND TECHNOLOGY, Issue 10 2003Markus Durban Abstract Phospholipase C (PLC, EC 3.1.4.3) enzymes specifically hydrolyze the C-O-P-bond in phospholipids, yielding sn -1, 2(2, 3)-diglycerides and a phosphate residue bearing the corresponding head group. Biochemical characterization of PLC requires methods for determination of activity. During characterization and purification, proteins are separated by polyacrylamide gel electrophoresis (PAGE). For direct identification and visualization of PLC, a new assay for activity staining in native and renatured SDS-PAGE is described. Incubation of a gel containing an active PLC in the presence of ,-naphthylphosphorylcholine leads to ,-naphthol formation. This reacts with the diazonium salt Fast Red, forming a red dye which allows clear determination of PLC purity, molecular weight and substrate specificity. The assay was verified using commercially available PC-PLC and new PC-PLC-producing Bacillus cereus strains. The substrate ,-NPC was prepared by chemical synthesis at an overall yield of 12%. [source] Hydroxyl-terminated hyperbranched aromatic poly(ether-ester)s: Synthesis, characterization, end-group modification, and optical propertiesJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 16 2008Thiyagarajan Shanmugam Abstract Novel AB2 -type monomers such as 3,5-bis(4-methylolphenoxy)benzoic acid (monomer 1), methyl 3,5-bis(4-methylolphenoxy) benzoate (monomer 2), and 3,5-bis(4-methylolphenoxy)benzoyl chloride (monomer 3) were synthesized. Solution polymerization and melt self-polycondensation of these monomers yielded hydroxyl-terminated hyperbranched aromatic poly(ether-ester)s. The structure of these polymers was established using FTIR and 1H NMR spectroscopy. The molecular weights (Mw) of the polymers were found to vary from 2.0 × 103 to 1.49 × 104 depending on the polymerization techniques and the experimental conditions used. Suitable model compounds that mimic exactly the dendritic, linear, and terminal units present in the hyperbranched polymer were synthesized for the calculation of degree of branching (DB) and the values ranged from 52 to 93%. The thermal stability of the polymers was evaluated by thermogravimetric analysis, which showed no virtual weight loss up to 200 °C. The inherent viscosities of the polymers in DMF ranged from 0.010 to 0.120 dL/g. End-group modification of the hyperbranched polymer was carried out with phenyl isocyanate, 4-(decyloxy)benzoic acid and methyl red dye. The end-capping groups were found to change the thermal properties of the polymers such as Tg. The optical properties of hyperbranched polymer and the dye-capped hyperbranched polymer were investigated using ultraviolet-absorption and fluorescence spectroscopy. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 5414,5430, 2008 [source] Surface-enhanced Raman scattering study of the red dye laccaic acidJOURNAL OF RAMAN SPECTROSCOPY, Issue 10 2007M. V. Cañamares Abstract FT-Raman and surface-enhanced Raman scattering (SERS) spectroscopy were applied to the study of lac dye, a highly fluorescent anthraquinone red dye. The SERS spectra were obtained at different pH values, on Ag nanoparticles prepared by chemical reduction with citrate and hydroxylamine, and at several excitation wavelengths, in order to find the best experimental conditions for the detection of the lac dye. The lower detection limit was achieved using nanoparticles prepared by reduction with hydroxylamine, excitation at 514.5 nm, and slightly acidic pH conditions, thus exploiting a combination of factors including lower electrostatic repulsion between dye and nanoparticles and resonance Raman enhancement. A comparison between the adsorption of laccaic acid (LA) and carminic acid (CA), another anthraquinone red dye, was also done, based on the SERS spectra of both dyes. Copyright © 2007 John Wiley & Sons, Ltd. [source] Dual-Color Fluorescence Cross-Correlation Spectroscopy Using Single Laser Wavelength ExcitationCHEMPHYSCHEM, Issue 4 2004Ling Chin Hwang Spotlight on interactions: The authors show that single wavelength excitation fluorescence cross-correlation spectroscopy (SW-FCCS) is possible using only one laser beam to excite a combination of labels, in work performed with studied FRET (fluorescence resonance energy transfer) dyes and quantum dots. They demonstrate that equilibrium binding and stoichiometry can easily be determined (see graphic; QR,=,quantum red dye, BF,=,fluorescein-labeled biotin). SW-FCCS is a promising tool for high-throughput screening applications as well as for the measurement of molecular interactions. [source] A study of novel bisazo reactive red dyes with good wet fastnessCOLORATION TECHNOLOGY, Issue 4 2009Zhuan Wang Three series of bisazo reactive red dyes were synthesised using 6-amino-1-naphthol-3-sulphonic acid and its derivatives as the coupling components. The dyeing parameters and wash fastness of these dyes on knitted cotton were evaluated and the relationships between the structure and dyeing properties were investigated. It was found that the hydrophilic groups introduced into the dye molecules decrease the substantivity and fixation of the dyes, but increase the build-up and migration properties. The defined wash-off factor can directly reflect the wash fastness of the dyes and the build-up property can be improved by commercialisation using certain auxiliaries. The results indicate that there is the possibility of synthesising a red reactive dye with a satisfying balance between high fixation and good wash fastness and several such dyes have been developed. 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