The Shopl'skil Effect as an Analytical Tool

Lima, Clausius G. de; Wehry, Ε. L.

doi:10.1080/10408348608542787

Cited by 10 publications

(11 citation statements)

References 85 publications

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“…However, literature values clearly show that LODs decrease when a powerful excitation source or lower temperatures are used. 2 Our results compare well with m ost of the reported values from the use of laser excitation at 77 K.…”

Section: Resultssupporting

confidence: 89%

Time-Resolved Laser-Excited Shpol'skii Spectrometry with a Fiber-Optic Probe and ICCD Camera

2000

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Improved methodology for chemical analysis via laser-excited Shpol'skii spectrometry is reported. The complications of traditional methodology for measurements at liquid nitrogen temperature are avoided by freezing the distal end of a bifurcated fiber-optic probe directly into the sample matrix. Emission wavelength-time matrices were rapidly collected by automatically incrementing the gate delay of an intensified charge-coupled device (ICCD) camera relative to the laser excitation pulse. The excitation source is a compact frequency-doubled tunable dye laser whose bandwidth (<0.03 nm) is well matched for Shpol'skii spectroscopy. Data reproducibility for quantitative analysis purposes and analytical figures of merit are demonstrated for several polycyclic aromatic hydrocarbons at 77 K. Although not attempted in this study, time-resolved excitation-emission matrices could easily be collected with this instrumental system.

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Section: Resultssupporting

confidence: 89%

Time-Resolved Laser-Excited Shpol'skii Spectrometry with a Fiber-Optic Probe and ICCD Camera

2000

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“…On the following day, when the number of cells reached 4 Â 10 5 cells/ml, oleic acid, diluted in ethanol, was added to the final concentration of 50 lM. Previous study has shown that higher concentrations of oleic acid are toxic to Jurkat cells [25]. Control cells were treated with the same amount of ethanol, which was always lower than 0.05%.…”

Section: Cell Treatmentmentioning

confidence: 99%

Identification of genes regulated by oleic acid in Jurkat cells by suppressive subtractive hybridization analysis

et al. 2004

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In this study, the effect of oleic acid (50 microM) on gene expression of Jurkat cells (human T lymphocytes cell line) was examined using the suppressive subtractive hybridization approach. This technique allowed us to identify genes with higher or lower expression after cell treatment with oleic acid as compared to untreated cells. Oleic acid upregulated the expression of the translation elongation factor alpha 1 and ATP synthase 8 and downregulated gp96 (human tumor rejection antigen gp96), heat-shock protein 60 and subtilisin-like protein 4. These results suggest that oleic acid, at plasma physiological concentration, can regulate the expression of important genes to maintain the machinery that ensures cell functioning.

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“…M easurements were taken from undegassed solutions in n-heptane, which was the selected solvent because it provides an appropriate Shpol'skii matrix for generic PACs analyses. 4,19,20 Site selective excitation was not attempted.…”

Section: Resultsmentioning

confidence: 99%

Fiber-Optic System for 77 K Phosphorescence Lifetime Measurements of Polycylic Aromatic Compounds in Shpol'skii Matrices

Martin

Campiglia

2001

Appl Spectrosc

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A fiber-optic system is reported for rapid, accurate, and precise 77 K measurements of relatively long phosphorescence lifetimes (τp = 200 ms). The instrument employs stimulated Raman scattering in connection with a pulsed laser source for sample excitation. Phosphorescence decay waveforms are collected at maximum emission wavelengths with a single channel detection system and the aid of a LabVIEW based in-house program acting as a data acquisition instrument, data storage device, and data interpreter. By means of program looping, up to 20 decays are recorded from a frozen sample in less than 5 min. A cryogenic fiber-optic probe directly frozen into the sample matrix removes the random errors associated with the classic sample freezing procedure and provides excellent reproducibility of measurements. The relative standard deviations of τp measured from several polycyclic aromatic compounds varied between 0 and 4.30%. The simplicity of the experimental procedure, the rather large τp differences observed from compounds within the same pollutant class, and the analytical figures of merit provide a solid foundation for pursuing low-temperature phosphorescence, time-resolved low-temperature phosphorescence, and low-temperature multidimensional luminescence analysis.

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The Shopl'skil Effect as an Analytical Tool

Cited by 10 publications

References 85 publications

Time-Resolved Laser-Excited Shpol'skii Spectrometry with a Fiber-Optic Probe and ICCD Camera

Time-Resolved Laser-Excited Shpol'skii Spectrometry with a Fiber-Optic Probe and ICCD Camera

Identification of genes regulated by oleic acid in Jurkat cells by suppressive subtractive hybridization analysis

Fiber-Optic System for 77 K Phosphorescence Lifetime Measurements of Polycylic Aromatic Compounds in Shpol'skii Matrices

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