			Home About us Contact

Fluorescent Emission (fluorescent + emission)

Distribution by Scientific Domains

Chemistry	42%
Physics and Astronomy	28%

Selected Abstracts

A Novel NADH Model: Design, Synthesis, and its Chiral Reduction and Fluorescent Emission

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 18 2009
Nai-Xing Wang
Abstract A novel chiral nicotinamide adenine dinucleotide hydrogen (NADH) model with C3 symmetry was designed and synthesized. Hydrogens at the C-4 position of all dihydropyridine rings in the inner part of the bowl could transfer to the substrate with powerful enantioselectivity. This novel C3 symmetrical NADH model is capable of fluorescence emission at 455,nm when excited at 390,nm. [source]

Detection of the irradiated donor in the LMXBs 4U 1636-536 (=V801 Ara) and 4U 1735-444 (=V926 Sco)

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 3 2006
J. Casares
ABSTRACT Phase-resolved VLT spectroscopy of the bursting low-mass X-ray binaries 4U 1636-536/V801 Ara and 4U 1735-444/V926 Sco is presented. Doppler images of the N iii,4640 Bowen transition reveal compact spots which we attribute to fluorescent emission from the donor star and enable us to define a new set of spectroscopic ephemerides. We measure Kem= 277 ± 22 and 226 ± 22 km s,1 from the N iii spots in V801 Ara and V926 Sco, respectively, which represent strict lower limits to the radial velocity semi-amplitude of the donor stars. Our new ephemerides provide confirmation that light-curve maxima in V801 Ara and likely V926 Sco occur at superior conjunction of the donor star and hence photometric modulation is caused by the visibility of the X-ray heated donor. The velocities of He ii,4686 and the broad Bowen blend are strongly modulated with the orbital period, with phasing supporting emission dominated by the disc bulge. In addition, a reanalysis of burst oscillations in V801 Ara, using our spectroscopic T0, leads to K1= 90,113 km s,1. We also estimate the K -corrections for all possible disc flaring angles and present the first dynamical constraints on the masses of these X-ray bursters. These are K2= 360 ± 74 km s,1, f(M) = 0.76 ± 0.47 M, and q= 0.21,0.34 for V801 Ara and K2= 298 ± 83 km s,1, f(M) = 0.53 ± 0.44 M, and q= 0.05,0.41 for V926 Sco. Disc flaring angles ,, 12° and q, 0.26,0.34 are favoured for V801 Ara whereas the lack of K1 constraint for V926 Sco prevents tight constraints on this system. Although both binaries seem to have intermediate inclinations, the larger equivalent width of the narrow N iii line in V801 Ara at phase 0.5 relative to phase 0 suggests that it has the higher inclination of the two. [source]

Measuring Tg in ultra-thin polymer films with an excimer fluorescence technique

POLYMER ENGINEERING & SCIENCE, Issue 9 2001
C. C. White
An excimer fluorescence technique has been applied to the measurement of Tg of ultra-thin polystyrene films. This technique utilizes an excimer-forming molecule with fluorescent emission in two wavelength bands. The intensity ratio of these bands is a sensitive measure of local viscosity. This technique has been applied to five polystyrene films in the thickness range of 25 nm to 200 nm supported on quartz substrates. The observed Tg for the five ultra-thin polymer films was similar to the bulk Tg with no observed dependence upon thickness. Additionally, the Tg determined for each film did not show any dependence upon thermal history. [source]

The first two-dimensional barium coordination polymer based on neutral and deprotonated 4-formylbenzoic acid

APPLIED ORGANOMETALLIC CHEMISTRY, Issue 11 2007
Zhao-Peng Deng
Abstract A two-dimensional barium(II) coordination polymer, [Ba(4-FBA)2(4-FBAH)]n (4-FBA, = 4-formylbenzoate), has been synthesized by the reaction of barium carbonate and 4-formylbenzoic acid. The barium(II) ion is nine-coordinated by eight O atoms from six deprotonated 4-FBA, ligands and one O atom from the terminal 4-FBAH ligand. Adjacent barium(II) ions are linked by the 4-FBA, ligand to furnish a two-dimensional lamellar structure which exhibits blue fluorescent emission in the solid state at room temperature. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Synthesis and Evaluation of Dual Wavelength Fluorescent Benzo[b]thiophene Boronic Acid Derivatives for Sugar Sensing

CHEMICAL BIOLOGY & DRUG DESIGN, Issue 4 2007
Senol Akay
Cell surface glycoproteins have been known to play very important roles in various physiologic and pathologic processes. Small molecule compounds capable of carbohydrate recognition can be very useful for the development of sensing, diagnostic, and therapeutic agents. Along this line, we are interested in developing water-soluble fluorescent boronic acid compounds for carbohydrate recognition. As such, a series of benzo[b]thiophene boronic acid derivatives have been synthesized and their fluorescent properties analyzed at physiologic pH. Benzo[b]thiophene derivatives were found to be a new type of fluorescent reporter compounds capable of dual fluorescent emission under physiologic pH conditions. Compounds 1, 3, 4, 5, and 6 showed unusual emission wavelength shifts upon binding of sugars. These boronic acids will be useful tools for building glycoprotein biosensors for biologic applications. [source]

Crystal Structure, Thermal Stability and Luminescence of Coordination Polymer [Cd(BBP)(p -PDOA)]n

CHINESE JOURNAL OF CHEMISTRY, Issue 8 2007
Yan Yang
Abstract Hydrothermal reaction of Cd(NO3)2·4H2O with bbp and p -PDOAH2 at 140 °C yielded a novel 1D cadmium(II) coordination polymer, [Cd(bbp)(p -PDOA)]n (bbp2,6-bis(benzimidazol-2-yl)pyridine, p -PDOAp -phenylenedioxy- diacetate dianion), in which CdN3O4 pentagonal bipyramids were linked by p -PDOA ligands in a bis-bidentate mode to construct a zigzag chain with the adjacent Cd···Cd distance of 1.14(1) nm. There exists a 2D supramolecular network linked by ,-, stacking with a face-to-face distance of 0.35(1) nm between the 2,6-bis(benzimidazol-2-yl) pyridine ligands and hydrogen-bonding interactions (0.27(4) nm). A 3D supramolecular network was further constructed by these non-covalent interactions between the zippers. The TG/DTG showed that its chain skeleton was thermally stable up to 389 °C and the blue fluorescent emission of the complex was determined at 428 nm in a solid state with its long decay lifetime of 7.24 ns. [source]

An image fiber based fluorescent probe with associated signal processing scheme for biomedical diagnostics

LASER PHYSICS LETTERS, Issue 10 2008
M. Vaishakh
Abstract A dual-modality image fiber based fluorescent probe that can be used for depth sensitive imaging and suppression of fluorescent emissions with nanosecond lifetime difference is proposed and illustrated in this paper. The system can give high optical sectioning and employs an algorithm for obtaining phase sensitive images. The system can find main application in in vivo biomedical diagnostics for detecting biochemical changes for distinguishing malignant tissue from healthy tissue. (© 2008 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA) [source]