Spectral Properties of Laser Dyes at varying Temperature

2020 ◽  
Author(s):  
H.R. Deepa ◽  
J. Thipperudrappa ◽  
H.M. Suresh Kumar
Keyword(s):  
Steady State ◽  
Fluorescence Lifetime ◽  
Fluorescence Intensity ◽  
Spectral Properties ◽  
Fluorescence Band ◽  
Laser Dyes ◽  
Dynamic Quenching ◽  
Positive Deviation ◽  
Quenching Effect ◽  
Transient Methods

Spectral properties of laser dyes 4-methyl-7-(4-morpholinyl)-2 H pyrano [2,3-b] pyridin-2-one (LD – 425) and 6,7,8,9-tetrahydro-6,8,9-trimethyl-4-(trifluoromrthyl)-2H-pyrano[2,3b][1,8]naphthyridin-2-one (LD – 489) have been investigated in the temperature range 250C - 650C by steady state and transient methods. Fluorescence intensity decreases with increase in temperature with fluorescence band maxima shifted towards shorter wavelength in both the dyes. Further, fluorescence lifetime has decreased with increase in temperature for LD - 425, whereas remained constant with change in temperature for LD - 489. The possible deactivation mechanisms are discussed. The quenching effect of these dyes in the presence of aniline at different temperature has been studied and the Stern-Volmer (S-V) plots are non-linear showing positive deviation. It has been observed that dynamic quenching constant increases with temperature, whereas static quenching constant is independent of temperature.

Influence of silver nanoparticles on absorption and fluorescence properties of laser dyes

2014 ◽  
Vol 92 (2) ◽  
pp. 163-167 ◽  
Author(s):  
H.R. Deepa ◽  
H.M. Suresh Kumar ◽  
M. Basanagouda ◽  
J. Thipperudrappa
Keyword(s):  
Silver Nanoparticles ◽  
Fluorescence Quenching ◽  
Room Temperature ◽  
Chemical Reduction ◽  
Mie Theory ◽  
Laser Dyes ◽  
Dynamic Quenching ◽  
Positive Deviation ◽  
Absorption And Fluorescence Spectroscopy ◽  
Quenching Process

The interaction of silver nanoparticles with four laser dyes, namely, LD-425, LD-489, LD-473, and LD-423, dispersed in methanol has been studied at room temperature by absorption and fluorescence spectroscopy. The silver nanoparticles were synthesized by chemical reduction and estimated size is 11 nm according to Mie theory. The changes in absorption spectrum of these dyes with the addition of silver nanoparticles suggest possible interaction with the silver nanoparticles. The magnitudes of the association constants are estimated using the Benesi–Hildebrand model. Fluorescence quenching has been observed for all the dyes with the addition of silver nanoparticles of different concentrations. The Stern–Volmer plots of fluorescence quenching in the case of LD-425 and LD-489 are found to be linear, suggesting the fluorescence quenching is because of the dynamic quenching process. But in the case of LD-473 and LD-423, the Stern–Volmer plots are nonlinear showing positive deviation and the fluorescence quenching in these dyes is because of static quenching processes. Also, it is found that the fluorescence quenching is not solely due to diffusion.

Evaluation of Single-Hole Hydraulic Tests in Fractured Crystalline Rock by Steady-State and Transient Methods: A Comparison

1985 ◽  
Vol 50 ◽  
Author(s):  
J-E. Andersson ◽  
O. Persson
Keyword(s):  
Steady State ◽  
Hydraulic Conductivity ◽  
Flow Pattern ◽  
Transient Analysis ◽  
Crystalline Rock ◽  
Steady State Analysis ◽  
Single Hole ◽  
The Mean ◽  
Transient Methods ◽  
State Analysis

AbstractThe results from a large number of single-hole packer tests in crystalline rock from three test sites in Sweden have been analysed statistically. Average hydraulic conductivity values for 25 m long test intervals along boreholes with a maximal length of about 700 m are used in this study. A comparison between steady state and transient analysis of the same test data has been performed.The mean vaule of the hydraulic conductivity determined from steady state analysis was found to be about two to three times higher compared to transient analysis. However, in some cases the steady state analysis resulted in 10 to 20 times higher values compared to the transient analysis. Such divergence between the two analysis methods may be caused by deviations from the assumed flow pattern, borehole skin effects and influence of hydraulic boundaries.

A Profoundly Touchy Approved Spectrofluorimetric Approach for Assurance of Ixabepilone as Anticancer Drug by Utilizing Its Quenching Impact on Acetoxymercuric Fluorescein Reagent

2021 ◽  
pp. 39-52
Author(s):  
Hesham Salem ◽  
Amany Abdelaziz ◽  
Aliaa Gamal ◽  
Ramy El Sabaa
Keyword(s):  
Human Plasma ◽  
Anticancer Drug ◽  
Fluorescence Intensity ◽  
Solution Concentration ◽  
Quenching Effect ◽  
Bulk Powder ◽  
Optimized Conditions ◽  
Temperature Time ◽  
Sulfur Containing ◽  
Satisfactory Recovery

A dependable, sensitive, basic and cheap spectrofluorimetric approach has been created for test of sulfur-containing drug; ixabepilone in bulk powder, vials and human plasma. The approach depends on the quenching effect of ixabepilone on the fluorescence intensity of acetoxymercuric fluorescene (AMF) reagent at λem of 530 nm and λex of 500 nm. Parameters which will control the reaction such as pH, AMF solution concentration, temperature, time and solvents were examined and optimized. According to the optimized conditions, the proposed approach was practiced over the concentration area of 20-100 ng mL-1 with adequate linearity (r = 0.9998). The developed approach was approved confirming to ICH rules in terms of accuracy, precision, linearity, LOD and LOQ. The proposed approach was practiced to analyze ixabepilone in Ixempra® vials with satisfactory recovery % of 99.89 and RSE% of 1.24. The results achieved were compared to those achieved by an already reported HPLC approach.

scholarly journals Time-resolved and temperature tuneable measurements of fluorescent intensity using a smartphone fluorimeter

The Analyst ◽  
2017 ◽  
Vol 142 (11) ◽  
pp. 1953-1961 ◽  
Author(s):  
Md Arafat Hossain ◽  
John Canning ◽  
Zhikang Yu ◽  
Sandra Ast ◽  
Peter J. Rutledge ◽  
...  
Keyword(s):  
Steady State ◽  
Fluorescence Intensity ◽  
Time Resolved Fluorescence ◽  
Time Resolved ◽  
Fluorescent Intensity ◽  
Intensity Measurements

A smartphone fluorimeter is demonstrated for steady-state and time-resolved fluorescence intensity measurements at tunable temperatures.

P-glycoprotein-mediated secretion of a fluorescent cyclosporin analogue by teleost renal proximal tubules

1995 ◽  
Vol 268 (1) ◽  
pp. F46-F52 ◽  
Author(s):  
U. Schramm ◽  
G. Fricker ◽  
R. Wenger ◽  
D. S. Miller
Keyword(s):  
Steady State ◽  
Fluorescence Intensity ◽  
Fundulus Heteroclitus ◽  
Organic Anion ◽  
Proximal Tubules ◽  
Metabolic Inhibitors ◽  
Epifluorescence Microscopy ◽  
Transport Systems ◽  
Simple Diffusion ◽  
P Glycoprotein

The transport of a fluorescent cyclosporin analogue was measured in killifish (Fundulus heteroclitus) proximal tubules by means of epifluorescence microscopy and digital image analysis. Renal cells rapidly accumulated the cyclosporin analogue from the medium and attained steady state within 60 min; luminal fluorescence increased over the first 60-90 min. At steady state, luminal fluorescence intensity was two to three times higher than cellular. Cellular fluorescence intensity was a linear function of medium substrate concentration and was not affected by any treatment used. In contrast, luminal fluorescence exhibited a saturable component as the medium concentration of the cyclosporin was increased. Secretion into the lumen was blocked by metabolic inhibitors, vanadate, other cyclosporins, such as cyclosporin A and cyclosporin G, and substrates for P-glycoprotein (verapamil, vinblastine, and quinine) but not by substrates for the renal organic anion or organic cation transport systems, such as p-aminohippurate or tetraethylammonium. The data are consistent with the fluorescent cyclosporin analogue entering proximal tubule cells by simple diffusion and then being pumped into the tubular lumen by P-glycoprotein.

Steady-state thermal measurement of moist granular earthen materials

2016 ◽  
Vol 41 (2) ◽  
pp. 101-119 ◽  
Author(s):  
Robin E Clarke ◽  
Andrea Pianella ◽  
Bahman Shabani ◽  
Gary Rosengarten
Keyword(s):  
Thermal Conductivity ◽  
Steady State ◽  
Contact Resistance ◽  
Test Method ◽  
Single Specimen ◽  
Thermal Measurement ◽  
Moisture Contents ◽  
Difference Measurement ◽  
Transient Methods ◽  
Loose Fill

A technique based on the heat flow meter method is proposed for measuring the thermal conductivity of moist earthen and granular loose-fill materials. Although transient methods have become popular, this steady-state approach offers an uncertainty that can be reliably estimated and a test method that is widely accepted for building certification purposes. Variations to the standard method are proposed, including the use of a rigid holding frame with stiff base and silicone sponge buffer sheets, in conjunction with difference measurement to factor out the contributions from base, buffers and contact resistance. Using this approach, results are presented for green-roof substrates based on scoria, terracotta and furnace-ash at different moisture contents. Thermal conductivity ranged from 0.13 to 0.80 W/m K and fitted well to linear regression plots against moisture content. Further comparative measurements of a single specimen showed that direct measurement was less consistent than difference measurement and thus indicated that thermal resistance was higher by 0.023 m2 K/W, attributable to the presence of contact resistance.

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