scholarly journals Optically Dilute, Absorbing, and Turbid Phantoms for Fluorescence Spectroscopy of Homogeneous and Inhomogeneous Samples

1993 ◽  
Vol 47 (12) ◽  
pp. 2114-2121 ◽  
Author(s):  
A. J. Durkin ◽  
S. Jaikumar ◽  
R. Richards-Kortum
Keyword(s):  
Optical Properties ◽  
Fluorescence Spectra ◽  
Flavin Adenine Dinucleotide ◽  
Emission Spectra ◽  
Hemoglobin Concentration ◽  
Scattering Coefficient ◽  
Polystyrene Microspheres ◽  
Fluorescence Excitation ◽  
Structure Boundary ◽  
Optical Properties Of Tissue

This paper presents a phantom which simulates the optical properties of tissue. The phantom absorption coefficient, scattering coefficient, anisotropy factor, and fluorescence quantum yield can be independently varied to investigate the effects of these parameters on fluorescence excitation and emission spectra from 300 to 650 nm. Phantom fluorophores include Flavin Adenine Dinucleotide (FAD) and Rhodamine B. Absorption is controlled by adjusting phantom hemoglobin concentration. On the basis of their smoothly varying scattering coefficient and the relatively low amount of fluorescence contributed to the mixture in comparison to other available scatterers, 1.05-µm-diameter polystyrene microspheres were selected as a scatterer. Sample inhomogeneities are simulated by preparing the phantom in a gelatin substrate. The optical properties of turbid phantoms determined with the use of indirect techniques agree well with known values as long as µs(l – g) > µa. Data are presented from dilute, absorbing, and turbid phantoms and inhomogeneous phantoms to qualitatively illustrate the effects of optical properties and sample geometry on fluorescence spectra. The phantom provides the framework for detailed quantitative investigations of the effects of optical properties, sample size, shape, and structure, boundary conditions, and collection geometry on fluorescence spectra.

Factors influencing fluorescence spectra of free porphyrins.

1988 ◽  
Vol 34 (4) ◽  
pp. 757-760 ◽  
Author(s):  
C F Polo ◽  
A L Frisardi ◽  
E R Resnik ◽  
A E Schoua ◽  
A M Batlle
Keyword(s):  
Ionic Strength ◽  
Fluorescence Spectra ◽  
Emission Spectra ◽  
Main Peak ◽  
Excitation Spectra ◽  
Fluorescence Excitation ◽  
Experimental Conditions ◽  
Organic Mixture ◽  
Carbonate Buffer ◽  
Factors Influencing

Abstract We recorded fluorescence excitation and emission spectra of uro- and coproporphyrin under different experimental conditions, to see how these conditions influence quantifications based on measurement of fluorescence intensity. We found that, for bands alpha and beta of the emission spectra and the main peak of the excitation spectra, fluorescence depends on pH and is minimal near pH 5 and near pH 7-7.5 for copro- and uroporphyrin, respectively. For band gamma of the emission spectra there was a constant decrease of fluorescence with increasing alkalinity of the solution. The intensity of porphyrin fluorescence also depends on ionic strength, reaching sharp maxima at 0.1 mol/L (for uroporphyrin) and 1 mol/L (for coproporphyrin). The organic mixture ethyl acetate:acetic acid (4:1 by vol), commonly used to extract porphyrins from biological samples, markedly diminishes the fluorescence of both porphyrins as compared with the same concentration of each porphyrin in aqueous acidic solvent. Furthermore, when we measured different ratios of uro:copro mixture at three distinct pHs and buffers, we found that at pH 10.5 (in carbonate buffer) the measured units of fluorescence depend only on total porphyrin concentration and not on the composition of the mixture.

Fluorescence spectroscopy of mechanical pulps III: Effect of chlorite delignification

1995 ◽  
Vol 73 (11) ◽  
pp. 1955-1959 ◽  
Author(s):  
Jennifer A. Olmstead ◽  
Jian H. Zhu ◽  
Derek G. Gray
Keyword(s):  
Fluorescence Spectroscopy ◽  
Fluorescence Intensity ◽  
Fluorescence Spectra ◽  
Lignin Content ◽  
Emission Spectra ◽  
Thermomechanical Pulp ◽  
Fluorescence Excitation ◽  
Lignin Removal ◽  
Mechanical Pulps ◽  
Almost All

Many paper and wood samples fluoresce, but the sources of the emission are not well understood. Fluorescence excitation and emission spectra of paper sheets prepared from thermomechanical pulp (TMP) and bleached chemithermomechanical pulp (BCTMP) showed that the emission from the BCTMP was significantly higher than that from the TMP. Removing almost all of the lignin from both pulps by means of an acid chlorite treatment did not reduce the fluorescence significantly. By means of an approximate correction for changes in sheet reflectivity caused by the chlorite treatment, the fluorescence intensity was found to increase with lignin removal. Clearly, fluorescence is not simply related to lignin content. Keywords: wood pulp, lignin, cellulose, fluorescence spectra, acid chlorite delignification.

Synthesis and Optical Properties of some Novel Bis-1,3,4-Oxadiazoles

2015 ◽  
Vol 1104 ◽  
pp. 131-135
Author(s):  
Hua Liu ◽  
Lin Lu ◽  
Dun Jia Wang
Keyword(s):  
Optical Properties ◽  
Fluorescence Spectra ◽  
Fluorescence Emission ◽  
Chloroform Solution ◽  
Emission Spectra ◽  
Pyridine Derivatives ◽  
Fluorescence Emission Spectra ◽  
H Nmr ◽  
Uv Illumination ◽  
Oxadiazole Derivatives

Three 2,6-bis (1,3,4-oxadiazol-2-yl) pyridine derivatives were synthesized and their structures were conformed by1H NMR, FTIR, MS techniques and elemental analysis. The UV–Vis absorption and fluorescence emission spectra of these compounds were investigated in chloroform solution. The results showed that these bis-1,3,4-oxadiazole derivatives had broad and strong absorption at 278−302 nm in the UV–Vis spectra and exhibited fluorescence emission at 338 −367 nm under UV illumination in fluorescence spectra. It was found that the nature of the substituents at benzene ring in bis-1,3,4-oxadiazole derivatives had a significant impact on their photoluminescence behaviors.

Biophysical characterization of human breast tissues by photoluminescence excitation-emission spectroscopy

2012 ◽  
Vol 36 (1) ◽  
pp. 53-62 ◽  
Author(s):  
Tatjana Dramićanin ◽  
Lea Lenhardt ◽  
Ivana Zeković ◽  
Miroslav D. Dramićanin
Keyword(s):  
Emission Spectroscopy ◽  
Fluorescence Spectra ◽  
Emission Spectra ◽  
Extracellular Proteins ◽  
Human Breast ◽  
Fluorescence Excitation ◽  
Biophysical Characterization ◽  
Malignant Breast ◽  
Breast Tissues

Abstract Fluorescence excitation-emission spectroscopy was used to investigate specimens of normal and malignant human breast tissues. Measurements were performed in two spectral regions: in the excitation range from 335nm to 400nm and emission range from 430nm to 625 nm, and in the excitation range from 400nm to 470nm and emission range from 500nm to 640 nm. It was found that fluorescence spectra are composed mainly of the emissions of extracellular proteins and that the differences in the intensity of their emissions reveal the changes in the tissue structure and morphology. These differences could be best observed in the emission spectra excited with 370 nm, 425nm and 455nm radiation. Statistical analysis revealed several spectral subregions that exhibited extremely significant statistical difference between normal and malignant breast tissues. The origin of these differences was elaborated, and prospects for optical diagnostics of breast cancer was discussed.

Enhancement of optical properties of poly (9,9′-di-n-octylfluorenyl-2,7-diyl) in conjugated polymer/TiO2 nanocomposites

2014 ◽  
Vol 92 (9) ◽  
pp. 1021-1025 ◽  
Author(s):  
Bandar Ali Al-Asbahi ◽  
Mohammad Hafizuddin Haji Jumali
Keyword(s):  
Optical Properties ◽  
Conjugated Polymer ◽  
Emission Spectra ◽  
Treatment Temperature ◽  
Nanocomposite Films ◽  
Glass Substrates ◽  
Solution Blending ◽  
Heat Treated ◽  
Blending Method ◽  
Splitting Energy

The influence of colloidal TiO2 nanoparticle contents on the optical properties of poly (9,9′-di-n-octylfluorenyl-2,7-diyl) conjugated polymer (PFO) has been investigated. The solution blending method was used to prepare homogenous PFO/TiO2 nanocomposite. The nanocomposite films were prepared on glass substrates using the spin-coating technique. The films were divided into two groups, the first was left to dry at room temperature while the second was heat-treated at 120 °C for 1 h. Absorption and emission spectra showed that the PFO existed in α- and β-phases morphology having monomeric, excimeric, and double excimeric states. In addition, both spectra revealed that TiO2 contents and heat treatment temperature extended the conjugation length of PFO. Finally, emission spectra for both cases exhibited decreasing in the line width of zero-phonon emission spectra and increasing in the vibronic splitting energy, upon increment of the TiO2, led to a significant increase in π-electron delocalization and lower degree in chain disorder.

The Synthesis and Electroluminescence Properties of 4-Benzofuranyl-1,8-Naphthalimide Derivatives

2012 ◽  
Vol 557-559 ◽  
pp. 1031-1036 ◽  
Author(s):  
Jian Xin Yang ◽  
Xiang Hui Wang
Keyword(s):  
Absorption Spectra ◽  
Fluorescence Spectra ◽  
Cycloaddition Reaction ◽  
Emission Spectra ◽  
Luminescent Properties ◽  
Quantum Yields ◽  
Absorption And Fluorescence Spectra ◽  
Maximum Brightness ◽  
Maximum Emission ◽  
Mild Conditions

A series of fluorescence compounds, 4-benzofuranyl-1,8-naphthalimides, were prepared through cycloaddition reaction from 4-ethynyl-1,8-naphthalimides and o-iodophenols which catalyzed by a Pd(PPh3)2Cl2 / CuI system under mild conditions. The intermediate material, 4-ethynyl-1,8- naphthalimide, was synthesized from 4-bromo-1,8- naphthalimide and trimethylsilyl- acetylene. The absorption and fluorescence spectra of 4-benzofuranyl-1,8- naphthalimides were studied and the quantum yields were measured. The maximum UV/vis absorption spectra were in the range of 375-400 nm and the maximum emission spectra were in the range of 470-510 nm. The electro- luminescent properties were also mensurated through a doped electroluminescent device which contains 1% 1,8-naphthalimides and 99% CBP (4,4'-N,N'-dicarbazole-biphenyl), It’s shown the maximum brightness reached 3700 cd/ m2 at 22.5V.

scholarly journals Seasonal cycle and source analyses of aerosol optical properties in a semi-urban environment at Puijo station in Eastern Finland

2012 ◽  
Vol 12 (12) ◽  
pp. 5647-5659 ◽  
Author(s):  
A. Leskinen ◽  
A. Arola ◽  
M. Komppula ◽  
H. Portin ◽  
P. Tiitta ◽  
...  
Keyword(s):  
Optical Properties ◽  
Paper Mill ◽  
Single Scattering ◽  
Single Scattering Albedo ◽  
Scattering Coefficient ◽  
Traffic Density ◽  
Aerosol Optical Properties ◽  
Absorption Coefficients ◽  
Data Set ◽  
Pollutant Sources

Abstract. We introduce a four-year (in 2006–2010) continuous data set of aerosol optical properties at Puijo in Kuopio, Finland. We study the annual and diurnal variation of the aerosol scattering and absorption coefficients, hemispheric backscattering fraction, scattering Ångström exponent, and single scattering albedo, whose median values over this period were 7.2 Mm−1 (at 550 nm), 1.0 Mm−1 (at 637 nm), 0.15, 1.93 (between 450 and 550 nm), and 0.85, respectively. The scattering coefficient peaked in the spring and autumn, being 2–4 times those in the summer and winter. An exception was the summer of 2010, when the scattering coefficient was elevated to ~300 Mm−1 by plumes from forest fires in Russia. The absorption coefficient peaked in the winter when soot-containing particles derived from biomass burning were present. The higher relative absorption coefficients resulted in lower single scattering albedo in winter. The optical properties varied also with wind direction and time of the day, indicating the effect of the local pollutant sources and the age of the particles. Peak values in the single scattering albedo were observed when the wind blew from a paper mill and from the sector without local pollutant sources. These observations were linked, respectively, to the sulphate-rich aerosol from the paper mill and the oxygenated organics in the aged aerosol, which both are known to increase the scattering characteristics of aerosols. Decreases in the single scattering albedo in the morning and afternoon, distinct in the summertime, were linked to the increased traffic density at these hours. The scattering and absorption coefficients of residential and long-range transported aerosol (two separate cloud events) were found to be decreased by clouds. The effect was stronger for the scattering than absorption, indicating preferential activation of the more hygroscopic aerosol with higher scattering characteristics.

Effect of UV Treatment on Optical Properties of Low-Density Polyethylene Films Doped with Eu(TTA)3phen Complex

2014 ◽  
Vol 895 ◽  
pp. 155-161
Author(s):  
M.I. Khairuldin ◽  
N.M.A. Aziz ◽  
N.M. Nashaain ◽  
S. Wedianti ◽  
I. Farehah ◽  
...  
Keyword(s):  
Optical Properties ◽  
Emission Spectra ◽  
Low Density Polyethylene ◽  
Rare Earth Complex ◽  
Low Density ◽  
Uv Treatment ◽  
Uv Spectrum ◽  
Light Manipulation ◽  
Emission Transition ◽  
Ft Ir

Low-Density Polyethylene (LDPE) films doped with Eu (TTA)3phen complex (TTA=2-thenoyltrifluoroacetone, phen=1,10-phenanthroline) were fabricated by hot-blowing technique for thickness of 100 μm. The films were doped with 0.1 % of Eu (TTA)3phen to the total weight of LDPE and exposed to UV irradiation from deuterium lamp for 5, 10, 20, 40 and 60 hours to investigate the effect of its optical properties. The films were characterized by Spectrofluorometer, UV/VIS Spectrophotometer and FT-IR Spectrometer to measure their emission spectra, lifetimes, transmission transparency and chemical bonding. Photoluminescence of the room-temperature Eu (TTA)3phen doped films consist of typical Eu3+emission transition lines with hypersensitive5D07F2emission band at 610 nm. After 20 hours UV treatment, the peak intensity dropped by 90 % and shortened the luminescent lifetimes from 0.654 ms to 0.305 ms. Longer UV treatment also has accelerated degradation in doped LDPE films shown by significant reducing in absorption peak of FTIR at 3395, 3186 and 1645 cm-1. The results would provide a mechanism to improve the lifetime of the LDPE by utilizing the light-manipulation property of Eu (TTA)3phen complex to absorb UV spectrum and covert into red emission.Keywords: LDPE, rare-earth complex, photoluminescence

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