Universality of sol--gel phase transition ofκ-carrageenan in various salts: a steady state fluorescence study

2007 ◽  
Vol 80 (8) ◽  
pp. 799-812 ◽  
Author(s):  
Ö. Pekcan ◽  
Ö. Tari
Keyword(s):  
Phase Transition ◽  
Steady State ◽  
Sol Gel ◽  
Fluorescence Study ◽  
Steady State Fluorescence ◽  
Gel Phase

Gelation of PAAm-PVP composites: A fluorescence study

2014 ◽  
Vol 28 (20) ◽  
pp. 1450122 ◽  
Author(s):  
Gülşen Akin Evingür ◽  
Hakan Kaygusuz ◽  
F. Bedia Erim ◽  
Önder Pekcan
Keyword(s):  
Phase Transition ◽  
Free Radical ◽  
Classical Result ◽  
Fluorescence Spectra ◽  
Sol Gel ◽  
Vinyl Pyrrolidone ◽  
Fluorescence Study ◽  
New Class ◽  
Hybrid Hydrogels ◽  
Gel Phase

Hybrid hydrogels are a new class of composite materials. Polyacrylamide (PAAm) hydrogels are mainly produced by free radical crosslinking copolymerization (FCC) of AAm in the presence of N, N′-methylene bis (acrylamide) (BIS) as the crosslinker. Pyranine doped PAAm-poly (N-vinyl pyrrolidone) (PVP) composite were prepared with different amounts of PVP varying in the range between 0.0015 and 0.1 gr. It was observed that pyranine molecules as a fluoroprobe bind to AAm and PVP chains upon the initiation of the polymerization, causing the fluorescence spectra of the bonded pyranines shift to the shorter wavelengths. The sol–gel phase transition and its universality were monitored and tested as a function of PVP contents. Observations around the critical point show that the gel fraction exponent, β, agreed with the percolation result for below 0.025 gr PVP contents. However, classical result was observed above 0.0125 gr PVP content.

Sol-gel phase transition of brucine-appended porphyrin gelator: a study by vibrational circular dichroism spectroscopy

2002 ◽  
Vol 13 (24) ◽  
pp. 2661-2666 ◽  
Author(s):  
Vladimı́r Setnička ◽  
Marie Urbanová ◽  
Statis Pataridis ◽  
Vladimı́r Král ◽  
Karel Volka
Keyword(s):  
Phase Transition ◽  
Circular Dichroism ◽  
Sol Gel ◽  
Circular Dichroism Spectroscopy ◽  
Vibrational Circular Dichroism ◽  
Gel Phase ◽  
Circular Dichroïsm

scholarly journals PREPARATION OF CORE-SHELL SILVER/SILICA NANOPATICLES AND THEIR APPLICATION FOR ENHANCEMENT OF CYANINE 3 FLUORESCENCE

2012 ◽  
Vol 11 (04) ◽  
pp. 1240020 ◽  
Author(s):  
N. SUI ◽  
V. MONNIER ◽  
Z. YANG ◽  
Y. CHEVOLOT ◽  
E. LAURENCEAU ◽  
...  
Keyword(s):  
Steady State ◽  
Fluorescence Spectroscopy ◽  
Sol Gel ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
Steady State Fluorescence ◽  
Covalently Bonded ◽  
Core Shell Nanoparticles ◽  
Steady State Fluorescence Spectroscopy ◽  
Silver Core

Core shell Ag@SiO2 -Streptavidin- Cy3 nanoparticles were prepared. Ag@SiO2 nanoparticles were synthesized via a sol–gel method. Then, Streptavidin- Cy3 was covalently bonded to the Ag@SiO2 surface. These core-shell nanoparticles were characterized by steady-state fluorescence spectroscopy and fluorescence scanning. In presence of the silver core, a 2.5-time enhancement of Cy3 fluorescence intensity was obtained. This result shows that these nanoparticles can be potentially helpful in surface analysis based on biochip.

Quater-, Quinque-, and Sexithiophene Organogelators: Unique Thermochromism and Heating-Free Sol-Gel Phase Transition

2005 ◽  
Vol 11 (16) ◽  
pp. 4735-4742 ◽  
Author(s):  
Shin-ichiro Kawano ◽  
Norifumi Fujita ◽  
Seiji Shinkai
Keyword(s):  
Phase Transition ◽  
Sol Gel ◽  
Gel Phase

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.

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