Fluorescence-Excitation and Emission Spectra from LH2 Antenna Complexes of Rhodopseudomonas acidophila as a Function of the Sample Preparation Conditions

2013 ◽  
Vol 117 (40) ◽  
pp. 12020-12029 ◽  
Author(s):  
Ralf Kunz ◽  
Kõu Timpmann ◽  
June Southall ◽  
Richard J. Cogdell ◽  
Jürgen Köhler ◽  
...  
Keyword(s):  
Sample Preparation ◽  
Emission Spectra ◽  
Fluorescence Excitation ◽  
Rhodopseudomonas Acidophila ◽  
Preparation Conditions

Spherical BaMgAl10O17:Eu2+ Phosphor Particles by Liquid Phase Synthesis

2007 ◽  
Vol 124-126 ◽  
pp. 391-394
Author(s):  
Ha Kyun Jung ◽  
Dae Won Lee ◽  
Yoon Chang Park
Keyword(s):  
Liquid Phase ◽  
Emission Intensity ◽  
Broad Band ◽  
Emission Spectra ◽  
Luminescent Properties ◽  
Phase Reaction ◽  
Uniform Size ◽  
Synthetic Process ◽  
Preparation Conditions ◽  
Blue Phosphor

To improve luminescent properties of the phosphor, spherical BaMgAl10O17:Eu2+ particles have been synthesized using a liquid phase reaction composed of two-stage precipitations. This phosphor particles exhibited uniform size (0.4 ㎛) with narrow distribution and were well-dispersed without agglomeration. The single phase of phosphor was formed by firing at the temperature of about 1350°C. The preparation conditions in this synthetic process for spherical BaMgAl10O17:Eu2+ particles were optimized on the basis of emission intensity by the excitation at 147 nm. The emission spectra showed the typical broad band due to the transition of Eu2+ activator from 4f65d1 to 4f7 in BaMgAl10O17:Eu2+. The maximum emission intensity for this spherical blue phosphor was obtained by reduction treatment at 1450°C.

Spectroanalytical Parameters of Fungal Metabolites. IV. Moniliformin

1974 ◽  
Vol 57 (6) ◽  
pp. 1392-1396 ◽  
Author(s):  
J A Lansden ◽  
R J Clarkson ◽  
W C Neely ◽  
R J Cole ◽  
J W Kirksey
Keyword(s):  
Low Temperature ◽  
Aqueous Solutions ◽  
Ambient Temperature ◽  
Emission Spectrum ◽  
Potassium Salt ◽  
Emission Spectra ◽  
Fungal Metabolites ◽  
Fungal Metabolite ◽  
Fluorescence Excitation ◽  
Phosphorescence Emission

Abstract The spectral data for a novel fungal metabolite, moniliformin (potassium salt of 1-hydroxycyclobut- 1-ene-3,4-dione), are reported. The corrected ambient temperature fluorescence excitation and emission spectra are given and the quantum efficiency is calculated to be 5.32 × 10舓3. The uncorrected low temperature phosphorescence emission spectrum and lifetime are also reported. Other physical data are given to support spectral evidence that the molecule exists as a dimer in aqueous solutions.

Fluorescence excitation and emission spectra of 1,8‐dihydroxyanthraquinone‐d0 and ‐d2 in n‐octane at 10 K

1987 ◽  
Vol 87 (10) ◽  
pp. 5664-5669 ◽  
Author(s):  
Giulietta Smulevich ◽  
Paolo Foggi ◽  
Alessandro Feis ◽  
Mario P. Marzocchi
Keyword(s):  
Emission Spectra ◽  
Fluorescence Excitation

Effects of sample preparation conditions and short chains on space charge formation in LDPE

1996 ◽  
Vol 3 (2) ◽  
pp. 153-160 ◽  
Author(s):  
K.S. Suh ◽  
Jung Hoe Koo ◽  
Seung Hyung Lee ◽  
Jung Ki Park ◽  
T. Takada
Keyword(s):  
Sample Preparation ◽  
Space Charge ◽  
Charge Formation ◽  
Preparation Conditions

scholarly journals Spectroscopic studies on Tb3+ binding to S-100a protein

1987 ◽  
Vol 244 (3) ◽  
pp. 559-563 ◽  
Author(s):  
R S Mani ◽  
C M Kay
Keyword(s):  
Conformational Changes ◽  
Binding Assay ◽  
Emission Spectra ◽  
Spectroscopic Studies ◽  
Spectral Studies ◽  
Difference Spectroscopy ◽  
Fluorescence Excitation ◽  
Fluorescence Studies ◽  
Helical Content ◽  
Direct Binding

Direct binding assay and fluorescence studies revealed that S-100a protein binds 2 mol of Tb3+/mol of protein at pH 6.6. The protein binds Tb3+ much more tightly than Ca2+, and the upper limit of the observed Kd value for Tb3+ is 3.5 × 10(-6) M. The Tb3+-binding site on the protein must be close to a tyrosine residue, as indicated by fluorescence excitation and emission spectra, where energy transfer from tyrosine is noted. Addition of Tb3+ resulted in a conformational change in the protein, as revealed by u.v.-difference spectroscopy and c.d. studies. Far-u.v. c.d. studies indicated the helical content to decrease from approx. 39% to 35% in the presence of Tb3+. From u.v.-difference-spectroscopy results the single tryptophan and the tyrosine chromophores in S-100a protein are blue-shifted (i.e. exposed to the solvent) in the presence of Tb3+ and the observed conformational changes are similar to those induced by Ca2+, suggesting that Tb3+ can be employed as a Ca2+ analogue in spectral studies with S-100a protein.

Interactions of dyes with wool. Spectral and photochemical studies of fluorescent whitening agents

1977 ◽  
Vol 30 (1) ◽  
pp. 87 ◽  
Author(s):  
IH Leaver
Keyword(s):  
Energy Transfer ◽  
Polymer Films ◽  
Spectral Study ◽  
Emission Spectra ◽  
Electronic Energy ◽  
Fluorescence Excitation ◽  
Fluorescence Depolarization ◽  
Electronic Energy Transfer ◽  
Fluorescent Whitening Agents ◽  
Photochemical Behaviour

A spectral study has been made of the interactions of four types of fluorescent whitening agents with wool. Fluorescence excitation and emission spectra have been measured in single wool fibres, and are compared with the corresponding spectra in solution and in polymer films. The polarity of the environment has a pronounced effect on the fluorescence properties of the whiteners in solution, but generally has little effect in rigid media. The emission spectra in wool are found to be strongly influenced by the concentration of whitener in the fibre. This heterogeneity of the fluorescence is attributed both to aggregation of the whitener and to changes in the polarity of its micro-environment in the fibre. The results of fluorescence depolarization studies indicate that electronic energy transfer between whitener molecules occurs efficiently at the concentrations normally used for whitening wool. Critical transfer distances and concentrations have been determined for the various whiteners, and are compared with the values predicted by Forster's theory of dipole-dipole transfer. The photochemical behaviour of the fluorescent whiteners in wool has been examined, and the effects of oxygen and water on the fading rates are discussed.

On-the-Fly Fluorescence Lifetime Detection of Humic Substances in Capillary Electrophoresis

2003 ◽  
Vol 57 (3) ◽  
pp. 256-265 ◽  
Author(s):  
Joseph D. Hewitt ◽  
Linda B. McGown
Keyword(s):  
Humic Substances ◽  
Fluorescence Lifetime ◽  
Spectral Characteristics ◽  
Emission Spectra ◽  
Fulvic Acids ◽  
Fluorescence Decay ◽  
Fluorescence Excitation ◽  
Lifetime Analysis ◽  
Decay Profile ◽  
Fluorescence Lifetime Detection

On-the-fly fluorescence lifetime detection was investigated as a tool for studying humic substances in capillary zone electrophoresis (CZE). Humic substances are complex, heterogeneous mixtures of natural products that tend to migrate in a single, broad CZE peak. The intrinsic fluorescence lifetime of five humic substances from the International Humic Substances Society (IHSS) was monitored using excitation at 488 or 364 nm to produce intensity-lifetime electropherograms for each of the substances. Each frequency-domain lifetime measurement, collected at sub-second intervals during the CZE run, contains the equivalent of a complete decay profile. Lifetime analysis of each decay profile was used to construct a lifetime-resolved electropherogram for each lifetime component, from which the variation in relative intensity contributions of each lifetime across the broad CZE peak could be determined. Absorption spectra, fluorescence excitation–emission spectra, and lifetime profiles of batch solutions of the samples were determined as well. It was found that, whereas absorption and fluorescence spectral characteristics tended to discriminate between humic acids and fulvic acids, the batch solution lifetime profiles discriminated instead between samples from different sources, regardless of fraction. On-the-fly lifetime detection provided a more detailed view of the fluorescence decay of the samples, including greater resolution of lifetimes for two of the fulvic acids and greater discrimination among samples based on lifetime profiles across the CZE peaks.

PARAFAC modeling of fluorescence excitation−emission spectra for rapid assessment of compost maturity

2010 ◽  
Vol 101 (21) ◽  
pp. 8244-8251 ◽  
Author(s):  
Guang-Hui Yu ◽  
Yi-Hong Luo ◽  
Min-Jie Wu ◽  
Zhu Tang ◽  
Dong-Yang Liu ◽  
...  
Keyword(s):  
Rapid Assessment ◽  
Emission Spectra ◽  
Fluorescence Excitation ◽  
Compost Maturity

Classification of Organic and Biological Materials with Deep Ultraviolet Excitation

2008 ◽  
Vol 62 (10) ◽  
pp. 1070-1077 ◽  
Author(s):  
Rohit Bhartia ◽  
Willam F. Hug ◽  
Everett C. Salas ◽  
Ray D. Reid ◽  
Kripa K. Sijapati ◽  
...  
Keyword(s):  
Emission Spectra ◽  
Principal Component ◽  
Biological Materials ◽  
Bacterial Spores ◽  
Fluorescence Excitation ◽  
Native Fluorescence ◽  
Whole Cells ◽  
Or Groups ◽  
Polycyclic Aromatic ◽  
Deep Ultraviolet

We show that native fluorescence can be used to differentiate classes or groups of organic molecules and biological materials when excitation occurs at specific excitation wavelengths in the deep ultraviolet (UV) region. Native fluorescence excitation–emission maps (EEMs) of pure organic materials, microbiological samples, and environmental background materials were compared using excitation wavelengths between 200–400 nm with emission wavelengths from 270 to 500 nm. These samples included polycyclic aromatic hydrocarbons (PAHs), nitrogen- and sulfur-bearing organic heterocycles, bacterial spores, and bacterial vegetative whole cells (both Gram positive and Gram negative). Each sample was categorized into ten distinct groups based on fluorescence properties. Emission spectra at each of 40 excitation wavelengths were analyzed using principal component analysis (PCA). Optimum excitation wavelengths for differentiating groups were determined using two metrics. We show that deep UV excitation at 235 (±2) nm optimally separates all organic and biological groups within our dataset with >90% confidence. For the specific case of separation of bacterial spores from all other samples in the database, excitation at wavelengths less than 250 nm provides maximum separation with >6σ confidence.

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