Fluorescence of Tetrols, Tetrols Complexed with DNA, and Benzo[a]Pyrene-DNA Adducts in Methanol/Water Solutions

2000 ◽  
Vol 54 (2) ◽  
pp. 287-293 ◽  
Author(s):  
Paul B. Steinbach ◽  
Robert J. Hurtubise
Keyword(s):  
Dna Adducts ◽  
Fluorescence Spectra ◽  
Fluorescence Emission ◽  
Dna Bases ◽  
Hydroxyl Groups ◽  
Excitation Spectra ◽  
Fluorescence Parameters ◽  
Water Composition ◽  
Hydrolysis Products ◽  
Definition Of

Several solution fluorescence parameters were acquired for the four tetrol hydrolysis products of benzo[ a]pyrene-trans-7,8-dihydrodiol-9,10-epoxide (BPDE)-DNA adducts, tetrols complexed with DNA, and BPDE-DNA adducts in several methanol/water solvents. The relative polarity of the environment for the tetrols and BPDE-DNA adducts was determined by using a modified definition of the R value that is commonly employed for pyrene. The R values for the tetrols and BPDE-DNA adducts were calculated by obtaining the ratios of the intensities of the two major fluorescence emission bands at 380 and 400 nm ( I380/ I400). The positions of the hydroxyl groups on the hydroaromatic ring of the tetrols were compared in reference to the R values and the changes in the R values as a function of methanol/water composition. This approach resulted in a method for determining whether the hydroxyl groups in the 9 and 10 positions were on the same side or opposite sides of a hydroaromatic ring. The tetrols intercalated between the DNA bases showed quite different fluorescence spectra compared to tetrols not complexed with DNA. Also, the quasi-intercalated BPDE-DNA adducts gave significant changes in the R values with an increase in methanol in the solvent, and excitation spectra showed large shifts and changes in shape with an increase in methanol. The approaches developed provide unique structural and polarity information on tetrols and BPDE-DNA adducts.

scholarly journals Luminescent Hybrid Materials Based on Curcumin Derivatives Embedded in Palygorskite

2018 ◽  
Vol 55 (1) ◽  
pp. 63-67
Author(s):  
Monica Florentina Raduly ◽  
Valentin Raditoiu ◽  
Alina Raditoiu ◽  
Luminita Eugenia Wagner ◽  
Viorica Amariutei ◽  
...  
Keyword(s):  
Hybrid Materials ◽  
Fluorescence Spectra ◽  
Fluorescence Emission ◽  
Emission Spectra ◽  
Hydroxyl Groups ◽  
Fluorescent Properties ◽  
Fluorescence Emission Spectra ◽  
Curcumin Derivatives ◽  
Absorption Studies ◽  
Inorganic Matrix

The seven curcumin derivatives were deposited on palygorskite in order to obtain hybrid materials. The fluorescence emission spectra of the obtained materials show a decrease in fluorescence intensity relative to the respective dyes, due to the environments around the dyestuff molecules created in the host matrices. Absorption studies show the best adsorption on the inorganic matrix, for the compounds with the hydroxyl groups. Correlating fluorescence spectra of hybrid materials with the results for absorption spectra of the dyes adsorbtion on the surface of the clay lead to the conclusion that a high percentage of the adsorbed dye had the effect of fluorescence quenching. Thus, it was confirmed that the fluorescent properties of hybrid materials depend on the interactions established between the fluorescent dyestuff and the inorganic network.

Correction of Fluorescence Spectra

1994 ◽  
Vol 48 (4) ◽  
pp. 436-447 ◽  
Author(s):  
J. W. Hofstraat ◽  
M. J. Latuhihin
Keyword(s):  
Absorption Spectra ◽  
Wavelength Range ◽  
Fluorescence Spectra ◽  
Fluorescence Emission ◽  
Emission Spectra ◽  
Wavelength Dependence ◽  
Excitation Spectra ◽  
Excitation Light ◽  
Radiative Processes ◽  
Sensing Applications

Several methods that can be applied to remove wavelength-dependent instrumental effects from fluorescence emission and excitation spectra have been investigated. Removal of such artifacts is necessary for the comparison of spectra that have been obtained on different instruments. Without correction, spectral line positions and relative intensities will be instrument-determined to a great extent. Furthermore, the application of adequate correction procedures provides excitation spectra which can be directly compared to absorption spectra; comparison of corrected excitation spectra and absorption spectra can be used to interpret the efficiency and pathways of radiative processes. Finally, corrected reflection spectra can be obtained, which can be directly transformed into absorption spectra and are useful for remote sensing applications. The methods that have been studied for the correction of emission spectra are the application of a standard lamp with calibrated spectral output and the use of fluorescence standards. The standards are a series of luminescent phosphors in polymer films and a solution of quinine sulfate dihydrate in perchloric acid, all provided with certified spectral emission values. For correction of excitation spectra, a quantum counter was applied. Several quantum counters were investigated. The best results were obtained for application of a mixture of the dyes basic blue and HITC, which provided good correction for the wavelength range 250 to 820 nm. No good quantum counters have been reported thus far for this (large) wavelength range. Correction for wavelength dependence of the excitation optics was realized by measurement of the excitation light intensity at the sample position and at the reference position with a Si photodiode. Correction factors for the excitation spectra were checked with a number of reference materials. Attention has also been paid to polarization-dependent effects that may occur in fluorescence spectra. The application of correction procedures was demonstrated for phytoplankton fluorescence spectra.

scholarly journals Spectral Properties of Hybrid of Rhodamine (6G) Dyes Doped Epoxy Resin Dissolved in Chloroform

2019 ◽  
Vol 16 (3(Suppl.)) ◽  
pp. 0764 ◽  
Author(s):  
Al-Hamdani Et al.
Keyword(s):  
Epoxy Resin ◽  
Quantum Efficiency ◽  
Fluorescence Spectra ◽  
Room Temperature ◽  
Rhodamine 6G ◽  
Energy Gap ◽  
Radiative Lifetime ◽  
Stokes Shift ◽  
Fluorescence Emission ◽  
Absorption And Fluorescence Spectra

            The research is dealing with the absorption and fluorescence spectra for the hybrid of  an Epoxy Resin doped with organic dye Rhodamine (R6G) of different concentrations (5*10-6, 5*10-5, 1*10-5, 1*10-4, 5*10-4) Mol/ℓ at room temperature. The Quantum efficiency Qfm, the rate of fluorescence emission Kfm (s-1), the non-radiative lifetime τfm (s), fluorescence lifetime τf and the Stokes shift were calculated. Also the energy gap (Eg) for each dye concentration was evaluated. The results showed that the maximum quantum efficiency 62 % and maximum stokes shift 96 nm was obtained in dye concentration 5*10-6 and 1*10-4. The energy gap ranges between 1.066 eV to 1.128 eV depending proportionally on the dye concentrations.

Physiological Significance of Overproduced Carotenoids in Transformants of the Cyanobacterium Synechococcus PCC7942

1999 ◽  
Vol 54 (3-4) ◽  
pp. 191-198
Author(s):  
Navassard V. Karapetyan ◽  
Ute Windhövel ◽  
Alfred R. Holzwarth ◽  
Peter Böger
Keyword(s):  
Protein Complexes ◽  
Photosynthetic Apparatus ◽  
Fluorescence Emission ◽  
Fluorescence Induction ◽  
Carotenoid Content ◽  
Excitation Spectra ◽  
Fluorescence Excitation ◽  
Whole Cells ◽  
Fluorescence Excitation Spectra ◽  
Synechococcus Pcc7942

Abstract The functional location of carotenoids in the photosynthetic apparatus of -crtB and -pys transformants of the cyanobacterium Synechococcus PCC7942 was studied and compared with a control strain -pFP 1-3. These transformants overproduce carotenoids due to the insertion of an additional foreign phytoene synthase gene. A higher carotenoid content was found for -crtB and -pys transformants both in whole cells and isolated membranes; the -crtB transformant was also enriched with chlorophyll. 77-K fluorescence emission and excitation spectra of the phycobilin-free membranes were examined for a possible location of overproduced carotenoids in pigment-protein complexes in situ. A similar ratio of the amplitudes of fluorescence bands at 716 and 695 nm emitted by photosystems I and II, found for the three strains, indicates that the stoichiometry between photosystems of the transformants was not changed. Overproduced carotenoids are not located in the core antenna of photosys­ tem I, since 77-K fluorescence excitation spectra for photosystem I of isolated membranes from the studied strains do not differ in the region of carotenoid absorption. When illuminated with light of the same intensity but different quality, absorbed preferentially by either carotenoids, chlorophylls or phycobilins, respectively, oxygen evolution was found always higher in the transformants -crtB and -pys than in -pFP 1-3 control cells. Identical kinetics of fluorescence induction of all strains under carotenoid excitation did not reveal a higher activity of photosystem II in cells enriched with carotenoids. It is suggested that overproduced carotenoids of the transformants are not involved in photosynthetic light-harvesting; rather they may serve to protect the cells and its membranes against photodestruction.

scholarly journals Electronic Spectra of 1-Phenylethylamine and its Derivatives in Supersonic Jets

1990 ◽  
Vol 10 (3) ◽  
pp. 169-175
Author(s):  
Seiji Yamamoto ◽  
Taeko Niwa ◽  
Mitsuo Ito
Keyword(s):  
Relaxation Process ◽  
Electronic Spectra ◽  
Fluorescence Spectra ◽  
Phenyl Group ◽  
Nonradiative Relaxation ◽  
Excitation Spectra ◽  
Fluorescence Excitation ◽  
Fluorescence Excitation Spectra ◽  
Dispersed Fluorescence ◽  
Asymmetric Carbon

The S1←S0 fluorescence excitation spectra and dispersed fluorescence spectra of jet-cooled (+)-, (-)- and (±)-1-phenylethylamine and their derivatives (amides) have been observed. The 0-0 band of the amine locates at 37,641 cm-1. The amides which were synthesized from (+)-amine or (-)-amine with (+)-tartaric acid are diastereomers. It was found that the two diastereomers give the identical spectra with the 0-0 band at 34,757 cm-1. No difference in the spectrum indicates that the excitation is localized in the phenyl group which is far from the asymmetric carbon causing diastereoism. It was also found that 1-phenylethylamine has a fast nonradiative relaxation process in the Sstate, but such a process is removed by the formation of the amide.

Coupled-cluster and density functional theory studies of the electronic 0–0 transitions of the DNA bases

2014 ◽  
Vol 16 (15) ◽  
pp. 6931-6941 ◽  
Author(s):  
Vasily A. Ovchinnikov ◽  
Dage Sundholm
Keyword(s):  
Density Functional Theory ◽  
Linear Response ◽  
Density Functional ◽  
Electronic Excitation ◽  
Dna Bases ◽  
Coupled Cluster ◽  
Excitation Spectra ◽  
Functional Theory

The 0–0 transitions of the electronic excitation spectra of the lowest tautomers of the four nucleotide (DNA) bases have been studied using linear-response approximate coupled-cluster singles and doubles (CC2) calculations.

Simultaneous determination of amlodipine besylate and valsartan using a micelle-enhanced first derivative synchronous spectrofluorimetric method and application in their co-formulated tablets

2015 ◽  
Vol 7 (19) ◽  
pp. 8060-8068 ◽  
Author(s):  
Sh. Shalan ◽  
N. El-Enany ◽  
F. Belal
Keyword(s):  
Simultaneous Determination ◽  
Fluorescence Spectra ◽  
Amlodipine Besylate ◽  
Excitation Spectra ◽  
First Derivative ◽  
System P ◽  
Spectrofluorimetric Method

Fluorescence spectra: (I) A and B are emission and excitation spectra of AML (2 μg mL−1) in methanol while A′ and B′ are spectra of AML in a SDS system. (II) A and B are emission and excitation spectra of VAL (2 μg mL−1) in methanol while A′ and B′ are spectra of VAL in a SDS system.

Preparation, Characterization and Spectroscopy of Eu3+ in Gd2O3 Nanorods

2008 ◽  
Vol 8 (3) ◽  
pp. 1398-1403 ◽  
Author(s):  
Liqin Liu ◽  
En Ma ◽  
Renfu Li ◽  
Xueyuan Chen
Keyword(s):  
Electron Microscopy ◽  
Fluorescence Spectra ◽  
Filling Factor ◽  
Energy Levels ◽  
Diffraction Field ◽  
X Ray Diffraction ◽  
Excitation Spectra ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

Eu3+:Gd2O3 nanorods were prepared by a hydrothermal method. X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy, and Fourier transform-infrared spectroscopy were used to characterize the resulting samples. Emission and excitation spectra were studied using xenon excited spectroscopic experiments at 10 K. Energy transfer from Gd3+ to Eu3+, from the band gap of the host to Eu3+, and from Eu3+ (S6) to Eu3+ (C2) was observed. The energy levels of Eu3+ at the C2 site of cubic Gd2O3 were experimentally determined according to the fluorescence spectra at 10 K, and fit well with the theoretical values. The standard deviation for the optimal fit was 12.9 cm−1. The fluorescent lifetime of 5D0 (2.3 ms at 295 K) was unusually longer than that of the bulk counterparts (0.94 ms), indicating a small filling factor (0.55) for the nanorod volume. However the lifetime of 5D1 was much shorter than that of the bulk counterparts, 65 μs at 10 K, 37 μs at 295 K.

Synthesis, characterization and fluorescence properties study of meso-tetrakis(1-arylpyrazole-4-yl)porphyrins

2005 ◽  
Vol 09 (06) ◽  
pp. 430-435 ◽  
Author(s):  
Can-Cheng Guo ◽  
Tie-Gang Ren ◽  
Jian Wang ◽  
Chun-Yan Li ◽  
Jian-Xin Song
Keyword(s):  
Elemental Analysis ◽  
Mass Spectra ◽  
Fluorescence Spectra ◽  
Fluorescence Emission ◽  
Red Shift ◽  
Fluorescence Properties ◽  
Quantum Yields ◽  
Fluorescence Quantum Yields ◽  
H Nmr ◽  
Reaction Condition

Five new meso-tetrakis(1-arylpyrazol-4-yl)porphyrins were synthesized to investigate their fluorescence properties. Preparation of these porphyrins was carried out by cyclization of tetramethoxypropane with substituted phenylhydrazine, followed by formylation to give the corresponding aldehydes, which reacted with pyrrole under the Adler reaction condition to get the target porphyrins (1a-1e). All the porphyrins were characterized by 1 H NMR, elemental analysis, UV-vis spectra and mass spectra. Red fluorescence emission of these porphyrins was observed in fluorescence spectra. Compared with meso-tetraphenylporphyrin (TPPH2), these meso-tetrakis(1-arylpyrazol-4-yl) porphyrins had a significant red shift in UV-vis and fluorescence spectra with increased fluorescence quantum yields.

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