scholarly journals Effect of PAF on polyrnorphonuclear leucocyte plasma membrane polarity: a fluorescence study

1993 ◽  
Vol 2 (2) ◽  
pp. 149-151 ◽  
Author(s):  
A. Kantar ◽  
P. L. Giorgi ◽  
R. Fiorini
Keyword(s):  
Plasma Membrane ◽  
Steady State ◽  
Polymorphonuclear Leukocytes ◽  
Fluorescence Emission ◽  
Emission Spectra ◽  
Blue Shift ◽  
Fluorescence Study ◽  
Polar Solvents ◽  
Fluorescence Emission Spectra ◽  
Steady State Fluorescence

The effect of PAF on the plasma membrane polarity of polymorphonuclear leukocytes (PMNs) was investigated by measuring the steady-state fluorescence emission spectra of 2-dimethylamino(6-1auroyl) naphthalene (Laurdan), which is known to be incorporated at the hydrophobic-hydrophilic interface of the bilayer, displaying spectral sensitivity to the polarity of its surrounding. Laurdan shows a marked steady-state emission blue-shift in non-polar solvents, with respect to polar solvents. Our results demonstrate that PAF (10−7M) induces a blue shift of the fluorescence emission spectra of Laurdan. These changes are blocked in the presence of the PAF antagonist, L-659,989. Our data indicate that the interaction between PAF and PMNs is accompanied by a decrease in polarity in the hydrophobic-hydrophilic interface of the plasma membrane.

scholarly journals Effect of Nedocromil Sodium on Polymorphonuclear Leukocyte Plasma Membrane

1994 ◽  
Vol 3 (7) ◽  
pp. S21-S24 ◽  
Author(s):  
A. Kantar ◽  
N. Oggiano ◽  
P. L. Giorgi ◽  
G. V. Coppa ◽  
R. Gabbianelli ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Steady State ◽  
Membrane Fluidity ◽  
Fluorescence Anisotropy ◽  
Polymorphonuclear Leukocyte ◽  
Polymorphonuclear Leukocytes ◽  
Plasma Membranes ◽  
Nedocromil Sodium ◽  
Plasma Membrane Fluidity ◽  
Steady State Fluorescence

The effect of nedocromil sodium on the plasma membrane fluidity of polymorphonuclear leukocytes (PMNs) was investigated by measuring steady-state fluorescence anisotropy of 1-[4-trimethylammonium-phenyl]-6-phenyl- 1,3,5-hexatriene (TMA-DPH) incorporated in the membrane. Our results show that nedocromil sodium 300 μM significantly decreased membrane fluidity of PMNs. The decrease in membrane fluidity of PMNs induced by fMLP was abolished in the presence of nedocromil sodium. These data suggest that nedocromil sodium interferes with the plasma membranes of PMNs and modulates their activities.

Solvatochromic and pH Switch Properties of a D–π–A Dye with benzo[b]thiophene as Donor Moiety

2021 ◽  
Author(s):  
Lili Feng ◽  
Pengyu Wang ◽  
Hansen Yang ◽  
Zhuo Chen ◽  
Shuhui Bo
Keyword(s):  
Color Change ◽  
Condensation Reaction ◽  
Fluorescence Emission ◽  
Emission Spectra ◽  
Polar Solvents ◽  
Fluorescence Emission Spectra ◽  
Knoevenagel Condensation Reaction ◽  
A Charge ◽  
Donor Moiety ◽  
Positive Solvatochromism

A charge transfer dye with the D–[Formula: see text]–A structure was synthesized by Pd catalyzed Hartwig–Buchwald coupling and Knoevenagel condensation reaction, using N, N-dihexylbenzo[b]thiophen-6-amine as donor and 2-(3-cyano-4, 5, 5-trimethylfuran-2 (5H)-ylidene)malononitrile (TCF) as acceptor. The solvatochromic and pH switch properties of the as-synthesized dye were investigated through UV-vis absorption and fluorescence emission spectra. A positive solvatochromism of the dye in different polar solvents was observed along with a visible color change of the solution. By adding acid/base into the DMSO solution of the dye, the color as well as the absorption and emission spectra of the solution exhibited outstanding characteristics of pH switch.

Photophysics of High Concentration Systems at a Solution / Solid Interface: An Evanescentwave Study

1996 ◽  
Vol 464 ◽  
Author(s):  
J.A. Elliott ◽  
G. Rumbles ◽  
A.J. De Mello ◽  
H.L. Anderson
Keyword(s):  
Total Internal Reflection ◽  
Fluorescence Emission ◽  
Emission Spectra ◽  
Inner Filter Effect ◽  
Bulk Solution ◽  
Laser Dye ◽  
High Concentration ◽  
Fluorescence Emission Spectra ◽  
Steady State Fluorescence ◽  
Rhodamine 101

ABSTRACTFor many species the study of photophysical behaviour by fluorescence spectroscopy has been confined to low concentration as a result of the influence of the inner filter effect. In this paper we report how the total internal reflection technique of evanescent wavefluorescence spectroscopy (EWIFS) allows both the collection of distortion free steady-state fluorescence emission spectra and quantitative analysis of such species, in ‘bulk’ solution environment, to significantly higher concentration than can be achieved with a conventional ( right-angle ) geometry. A study of two species, the laser dye rhodamine 101 and anovel meso-substituted zinc prophyrin is presented.

Optical Properties and Zinc Nitride Thin Films Prepared Using Magnetron Reactive Sputtering

2014 ◽  
Vol 940 ◽  
pp. 11-15
Author(s):  
Jun Qin Feng ◽  
Jun Fang Chen
Keyword(s):  
Thin Films ◽  
Band Gap ◽  
Near Infrared ◽  
Fluorescence Emission ◽  
Emission Spectra ◽  
Sem Images ◽  
Fluorescence Emission Spectra ◽  
Glass Substrates ◽  
Zinc Nitride ◽  
Direct Band

Zinc nitride films were deposited by ion sources-assisted magnetron sputtering with the use of Zn target (99.99% purity) on 7059 glass substrates. The films were characterized by XRD, SEM and EDS, the results of which show that the polycrystalline zinc nitride thin film can be grown on the glass substrates, the EDS spectrum confirmed the chemical composition of the films and the SEM images revealed that the zinc nitride thin films have a dense structure. Ultraviolet-visible-near infrared spectrophotometer was used to study the transmittance behaviors of zinc nitride thin films, which calculated the optical band gap by Davis Mott model. The results of the fluorescence emission spectra show the zinc nitride would be a direct band gap semiconductor material.

Stress and Phase Transformation Phenomena in Oxide Films: Real-Time Spectroscopic Measurements

1992 ◽  
Vol 271 ◽  
Author(s):  
Gregory J. Exarhos ◽  
Nancy J. Hess
Keyword(s):  
Phase Transformation ◽  
Applied Pressure ◽  
Oxide Films ◽  
Fluorescence Emission ◽  
Emission Spectra ◽  
Film Deposition ◽  
Optical Methods ◽  
Fluorescence Emission Spectra ◽  
Line Intensities ◽  
Deposition Parameters

ABSTRACTIn situ optical methods are reviewed for characterization of phase transformation processes and evaluation of residual stress in solution-deposited metastable oxide films. Such low density films most often are deposited as disordered phases making them prone to crystallization and attendant densification when subjected to increased temperature and/or applied pressure. Inherent stress imparted during film deposition and its evolution during the transformation are evaluated from phonon frequency shifts seen in Raman spectra (TiO2) or from changes in the laser-induced fluorescence emission spectra for films containing rare earth (Sm+3:Y3Al5O12) or transition metal (Cr+3 :Al2O3) dopants. The data in combination with measured increases in line intensities intrinsic to the evolving phase are used to follow crystallization processes in thin films. In general, film deposition parameters are found to influence the crystallite ingrowth kinetics and the magnitude of stress and stress relaxation in the film during the transformation. The utility of these methods to probe crystallization phenomena in oxide films will be addressed.

scholarly journals Fluorescence emission spectra of silver and silver/cobalt nanoparticles

2012 ◽  
Vol 19 (3) ◽  
pp. 943-947 ◽  
Author(s):  
Z. Parang ◽  
A. Keshavarz ◽  
S. Farahi ◽  
S.M. Elahi ◽  
M. Ghoranneviss ◽  
...  
Keyword(s):  
Fluorescence Emission ◽  
Emission Spectra ◽  
Cobalt Nanoparticles ◽  
Fluorescence Emission Spectra

pH sensitive smart gels of cetylpyridinium chloride in binary solvent mixtures: phase behaviour, structure and composition

RSC Advances ◽  
2015 ◽  
Vol 5 (62) ◽  
pp. 50306-50311 ◽  
Author(s):  
Illa Ramakanth ◽  
Jaromír Pištora
Keyword(s):  
Cetylpyridinium Chloride ◽  
Fluorescence Emission ◽  
Emission Spectra ◽  
Phase Behaviour ◽  
Binary Solvent ◽  
Solvent Mixtures ◽  
Gel Formation ◽  
Fluorescence Emission Spectra ◽  
Effect Of Ph ◽  
Binary Solvent Mixtures

Figure showing the effect of pH on CPC gel formation at 25 °C and fluorescence emission spectra of CPC solutions at pH ∼ 11.8.

scholarly journals The dependence of electrophoretic and spectroscopic properties of the pyruvate dehydrogenase complex on mono- and divalent ions.

1994 ◽  
Vol 41 (1) ◽  
pp. 63-72
Author(s):  
T Pawełczyk ◽  
R A Easom ◽  
M S Olson
Keyword(s):  
Ionic Strength ◽  
Pyruvate Dehydrogenase ◽  
Pyruvate Dehydrogenase Complex ◽  
Fluorescence Emission ◽  
Emission Spectra ◽  
Spectroscopic Properties ◽  
Uv Absorption ◽  
Divalent Ions ◽  
Fluorescence Emission Spectra ◽  
Dehydrogenase Complex

The effects of various mono- and divalent ions on the pyruvate dehydrogenase complex (PDC) were investigated. To determine the radius of PDC under various conditions a two-dimensional agarose gel electrophoresis technique was used. The radius of PDC cross-linked with glutaraldehyde at ionic strength 0.04 M was calculated to be 22.0 +/- 0.1 nm. The presence of K+, Na+ or HPO4(2-) prevented changes in electromobility and of the calculated radius of PDC induced by alteration in ionic strength. The fluorescence emission spectra of PDC depended on the ionic strength and monovalent cations. The fluorescence intensity of PDC increased in the presence of 80 mM K+, and decreased in the presence of 80 mM Na+ with no shift in the emission maximum wavelength. Changes in the ionic strength to which PDC was exposed resulted in alteration of the UV absorption spectra in the 230 nm region. These alterations were prevented by HPO4(2-), whereas Na+ or K+ ions had no effect on the UV absorption spectrum of PDC.

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