Cellulose Acetate-Based pH Indicator Optodes

1995 ◽  
Vol 48 (6) ◽  
pp. 1081 ◽  
Author(s):  
TJ Cardwell ◽  
RW Cattrall ◽  
LW Deady ◽  
M Dorkos ◽  
AJ Kaye ◽  
...  
Keyword(s):  
Cellulose Acetate ◽  
Ph Indicator ◽  
Ph Indicators

Some pH indicators for use in optode membranes based on cellulose acetate have been prepared, and applications of membranes containing octyl bis (2,4-dinitrophenyl)acetate in static and flowing systems are discussed.

Article

1999 ◽  
Vol 77 (5-6) ◽  
pp. 842-848 ◽  
Author(s):  
Duncan C Hone ◽  
Brian H Robinson ◽  
David C Steytler ◽  
Roger W Glyde ◽  
John A Cleverley
Keyword(s):  
Kinetic Studies ◽  
Hydrocarbon Chain ◽  
Water Soluble ◽  
Stopped Flow ◽  
Acid Neutralization ◽  
Ph Indicator ◽  
Ph Indicators ◽  
Hydrocarbon Chain Length ◽  
Overbased Detergent ◽  
Neutralization Rate

We have used stopped-flow kinetic studies to conduct an investigation into the acid neutralization reaction between overbased detergent additives and aqueous acid dispersed as w/o microemulsion droplets. Water-soluble pH indicators have been used to monitor the change in pH during the reaction. The acid neutralization rate was found to be dependent on the concentration of overbased additive, the temperature of the system, and the hydrocarbon chain length of the solvent. The systems are of importance in relation to the mechanism of acid neutralization by engine lubricants.Key words: overbased detergent additive, acid neutralization, pH indicator, stopped flow.

Fluorescence ratio imaging of dynamic intracellular ionic signals

1988 ◽  
Vol 46 ◽  
pp. 42-43
Author(s):  
R. Y. Tsien ◽  
A. Minta ◽  
M. Poenie ◽  
J.P.Y. Kao ◽  
A. Harootunian
Keyword(s):  
Binding Sites ◽  
Living Cells ◽  
Molecular Engineering ◽  
Ph Indicators ◽  
Highly Sensitive ◽  
Fluorescence Ratio Imaging ◽  
Ratio Imaging ◽  
Technical Advances ◽  
Indicator Dyes ◽  
Fluorescein Dyes

Recent technical advances now enable the continuous imaging of important ionic signals inside individual living cells with micron spatial resolution and subsecond time resolution. This methodology relies on the molecular engineering of indicator dyes whose fluorescence is strong and highly sensitive to ions such as Ca2+, H+, or Na+, or Mg2+. The Ca2+ indicators, exemplified by fura-2 and indo-1, derive their high affinity (Kd near 200 nM) and selectivity for Ca2+ to a versatile tetracarboxylate binding site3 modeled on and isosteric with the well known chelator EGTA. The most commonly used pH indicators are fluorescein dyes (such as BCECF) modified to adjust their pKa's and improve their retention inside cells. Na+ indicators are crown ethers with cavity sizes chosen to select Na+ over K+: Mg2+ indicators use tricarboxylate binding sites truncated from those of the Ca2+ chelators, resulting in a more compact arrangement of carboxylates to suit the smaller ion.

Cellulose Acetate Reverse Osmosis Membrane Structure

1972 ◽  
Vol 30 ◽  
pp. 528-529
Author(s):  
H. K. Plummer ◽  
E. Eichen ◽  
C. D. Melvin
Keyword(s):  
Cellulose Acetate ◽  
Reverse Osmosis ◽  
Membrane Structure ◽  
Freeze Drying ◽  
Dense Layer ◽  
Water Removal ◽  
Reverse Osmosis Membrane ◽  
Correct Interpretation ◽  
Electron Image ◽  
Scanning Electron

Much of the work reported in the literature on cellulose acetate reverse osmosis membranes has raised new and important questions with regard to the dense or “active” layer of these membranes. Several thickness values and structures have been attributed to the dense layer. To ensure the correct interpretation of the cellulose acetate structure thirteen different preparative techniques have been used in this investigation. These thirteen methods included various combinations of water substitution, freeze drying, freeze sectioning, fracturing, embedding, and microtomy techniques with both transmission and scanning electron microscope observations.It was observed that several factors can cause a distortion of the structure during sample preparation. The most obvious problem of water removal can cause swelling, shrinking, and folds. Improper removal of embedding materials, when used, can cause a loss of electron image contrast and, or structure which could hinder interpretation.

The Control of Cigarette Smoke Deliveries Using Heat-Shrinkable Films

1975 ◽  
Vol 8 (2) ◽  
Author(s):  
R. A. Crellin ◽  
G. O. Brooks ◽  
H. G. Horsewell
Keyword(s):  
Particulate Matter ◽  
Cellulose Acetate ◽  
Cigarette Smoke ◽  
Total Particulate Matter ◽  
Puff Volume ◽  
Cigarette Paper ◽  
High Degree

AbstractA ventilating filter for cigarettes has been developed which reduces the delivery of smoke constituents from the final two to three puffs. Since the normaI delivery for these three puffs can account for up to half the total particulate matter and nicotine delivered by the whole cigarette, usefuI reductions per cigarette can be produced. The ventilating filter consists of cellulose acetate tow wrapped in heat-shrinkable film and attached to a tobacco rod using perforated tipping paper. When the cigarette is smoked, the perforations remain closed by contact with the impermeable film until transfer of heat to the filter is sufficient to soften the filter tow and shrink the film. Ventilating air now enters the cigarette and reduces the smoke deliveries. The effectiveness of the ventilating filter is increased by using films which have a low shrink temperature, high shrink tension and a high degree of biaxiaI shrinkage. Increases in filter plasticiser level, tipping perforation area and puff volume improve the effectiveness of the ventilating filter but increases in cigarette paper porosity and tobacco butt length reduce the effectiveness

Characteristics and Potential Applications of Cellulose Acetate

2014 ◽  
Vol 68 (9) ◽  
pp. 1018-1024
Author(s):  
Shu Shimamoto ◽  
Shizuka Okada ◽  
Toshikazu Nakamura
Keyword(s):  
Cellulose Acetate ◽  
Potential Applications

Methods of testing cellulose acetate flake

1959 ◽  
Keyword(s):  
Cellulose Acetate
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