Factors Affecting Calibration for Phase-Modulation Fluorescence Lifetime Determinations

1986 ◽  
Vol 40 (4) ◽  
pp. 549-553 ◽  
Author(s):  
Kasem Nithipatikom ◽  
Linda B. McGown
Keyword(s):  
Fluorescence Lifetime ◽  
Phase Modulation ◽  
Solution Concentration ◽  
Resonance Peak ◽  
Photomultiplier Tube ◽  
Sample Solution ◽  
Excitation Wavelength ◽  
Reference Solution ◽  
Factors Affecting

The effects of several instrumental and experimental factors on phase-modulation fluorescence lifetime determinations of dimethyl POPOP, 9,10-diphenylanthracene, and benzo(a)pyrene were evaluated with the use of both a scattering solution and dimethylPOPOP as references for phase and modulation calibration. For the scattering solution reference, best results were obtained when the scatterer was measured within a few nanometers of the resonance peak corresponding to the excitation wavelength used for measuring the sample. Intensity matching of the reference (either scatterer or dimethylPOPOP) to the sample solution does not appear to be required as long as the sample solution exhibits lifetime homogeneity and the sample and reference are measured with the same voltage applied to the photomultiplier tube detector. Intensity matching to within 10–20% does appear to be indicated for samples with lifetime heterogeneity. When intensity matching is used, the intensities should be matched by adjustment of the reference solution concentration rather than by changing the wavelengths used to measure the reference.

Investigation on Polymer Adsorption and Retention in a Polymer Flooded Reservoir

2013 ◽  
Vol 734-737 ◽  
pp. 1200-1203
Author(s):  
Shu Qiang Liu ◽  
Ji Cheng Zhang ◽  
Jin Cheng Xu
Keyword(s):  
Polymer Solution ◽  
Influencing Factors ◽  
Polymer Adsorption ◽  
Solution Concentration ◽  
Injection Rate ◽  
The Other ◽  
Injection Time ◽  
Factors Affecting ◽  
Dynamic Factors ◽  
Polymer Retention

During polymer flooding, certain amount of polymer would be lost. Polymer retention causes sweep volume expanding on one side, it also causes polymer loss on the other. Therefore, it is a very important topic to study the influencing factors of polymer retention. There are many factors affecting polymer retention process. This paper mainly studied the influence from dynamic factors such as polymer solution concentration, injection rate, injection time, injected pv number. This paper investigated the influence of these factors on polymer retention process, and optimized these factors to minimize polymer loss in reservoir.

scholarly journals Fluorescence lifetime imaging of pH along the secretory pathway

2021 ◽  
Author(s):  
Peter Linders ◽  
Martin ter Beest ◽  
Geert van den Bogaart
Keyword(s):  
Temporal Resolution ◽  
Fluorescence Lifetime ◽  
Secretory Pathway ◽  
Fluorescent Protein ◽  
Excitation Wavelength ◽  
Fluorescence Lifetime Imaging ◽  
Ph Homeostasis ◽  
Ph Changes ◽  
Lifetime Imaging ◽  
Wide Range

Many cellular processes are dependent on correct pH levels, and this is especially important for the secretory pathway. Defects in pH homeostasis in distinct organelles cause a wide range of diseases, including disorders of glycosylation and lysosomal storage diseases. Ratiometric imaging of the pH-sensitive mutant of green fluorescent protein (GFP), pHLuorin, has allowed for targeted pH measurements in various organelles, but the required sequential image acquisition is intrinsically slow and therefore the temporal resolution unsuitable to follow the rapid transit of cargo between organelles. We therefore applied fluorescence lifetime imaging microscopy (FLIM) to measure intraorganellar pH with just a single excitation wavelength. We first validated this method by confirming the pH in multiple compartments along the secretory pathway. Then, we analyze the dynamic pH changes within cells treated with Brefeldin A, a COPI coat inhibitor. Finally, we followed the pH changes of newly-synthesized molecules of the inflammatory cytokine tumor necrosis factor (TNF)-α while it was in transit from the endoplasmic reticulum via the Golgi to the plasma membrane. The toolbox we present here can be applied to measure intracellular pH with high spatial and temporal resolution, and can be used to assess organellar pH in disease models.

scholarly journals Investigation of the factors affecting the photothermal therapy potential of small iron oxide nanoparticles over the 730–840 nm spectral region

2018 ◽  
Vol 17 (11) ◽  
pp. 1787-1793 ◽  
Author(s):  
K. Bilici ◽  
A. Muti ◽  
F. Demir Duman ◽  
A. Sennaroğlu ◽  
H. Yağcı Acar
Keyword(s):  
Iron Oxide ◽  
Iron Oxide Nanoparticles ◽  
Spectral Region ◽  
Photothermal Therapy ◽  
Laser Intensity ◽  
Excitation Wavelength ◽  
Oxide Nanoparticles ◽  
Factors Affecting

Photothermal activity of SPIONs is not dependent on the excitation wavelength, attenuation or laser intensity but to the power.

scholarly journals Proton release by tea plant (Camellia sinensis L.) roots as affected by nutrient solution concentration and pH

2012 ◽  
Vol 58 (No. 9) ◽  
pp. 429-434 ◽  
Author(s):  
Q. Wan ◽  
R.K. Xu ◽  
X.H. Li
Keyword(s):  
Linear Regression Analysis ◽  
Solution Concentration ◽  
Multiple Linear Regression Analysis ◽  
Solution Culture ◽  
Tea Plant ◽  
Charge Balance ◽  
Proton Release ◽  
Factors Affecting ◽  
Plant Body ◽  
Titration System

Solution culture experiments were conducted and the protons released were measured with an automatic titration system to determine the main factors affecting proton release by tea roots. Results indicated that the higher were the cation concentrations, the more protons were released from the roots, suggesting that tea roots took up a large amount of cations during growth, and then released protons to maintain charge balance of the plant body. The amount of protons released from tea roots at controlled pH was much higher than that in the treatments with uncontrolled pH. Stepwise multiple linear regression analysis showed that both NH<sub>4</sub><sup>+</sup>&nbsp;and Al(III) played distinct roles in proton release by tea plant roots. The uptake of Al(III) and NH<sub>4</sub><sup>+</sup>&nbsp;and subsequent release of protons may be an important mechanism for soil acidification in tea gardens.

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