Light intensity effect

Kinetic analysis. The observed light-intensity effect should permit a deeper insight into the mechanism of photoelectrochemical reactions. In this framework, a kinetic analysis of the stabilization process will now be made for an n-type compound semiconductor AB, which is being oxidized photoelectrochemically according to the over-all reaction equation... 

Light Intensity Effect. The effect of light intensity upon fhe polymerization rate at peak is displayed by three series of runs (.cf. Table IV). The series differ slightly In initial TR-14 concentration and temperature. Figure4 presents these data as log (rate at peak) vs. log (intensity). The rates plotted have been converted to rates at C = 0.0100 and T=313°K (40°C) by using R j OO = rC X (C/.01)0-35 X e+3l6(T"l-313-I). Considering the 30-... 

Series Lauryl TABLE IV Light Intensity Effect Acrylate Photopolymerizati on... 

YK Shen and GM Shen (1962) Studies on photophosphoryiation. II. The light intensity effect and intermediate steps of photophosphoryiation. Sci Sinica 11 1097-1106... 

Light Intensity Effect Lauryl Acrylate Photopolymerization... 

Figure 4. Light intensity effects on reaction exotherm at constant temperature and wavelength.

In one study [102], the expression for the autocatalytic reaction was modified to model diffusion effects (autoacceleration and vitrification) as well as the light intensity effect on the photopolymerization kinetics of a commercial acrylic resin. The parameters of the model were calculated using non-linear regression analysis. Expression of the rate constant k as k4.T)Io, where b is a fitting parameter and koiT) is temperature-dependent kinetic constant, enabled the authors to determine to the light intensity exponent. A value of about 0.7 was found, showing that the termination occurred following both monomolecular and bimolecular pathways. 

Shen YK, Shen GM (1962) Studies on photophosphorylation II. The "light intensity effect" and the intermediate steps of photophosphorylation,... 

Fig. 3.2.7 Left panel Effects of temperature on the luminescence intensity and stability of the protein P from Meganyctiphanes. The initial light intensity was measured with F plus P in 5 ml of 20 mM Tris-HCl/0.15 M NaCl, pH 7.5, at various temperatures. In the stability test, P was kept at the indicated temperature for 10 min, then mixed with 5 ml of 25 mM Tris-HCl/1 M NaCl, pH 7.59, containing F, to measure initial light intensity. Right panel Effect of the concentration of salts on the light intensity of the luminescence of F plus P, in 25 mM Tris-HCl, pH 7.6, at near 0°C. In the case of NaCl, the light intensity decreased to about a half after 10 min. From Shi-momura and Johnson, 1967, with permission from the American Chemical Society.

Fig. 4.5.3 Effect of temperature on the light intensity of coelenterazine catalyzed by Periphylla luciferases A, B, C and L, in 3 ml of 20 mM Tris-HCl, pH 7.8, containing 1 M NaCl and 0.05% BSA. The luminescence reaction was started by the addition of 10 (xl of 0.1 mM methanolic coelenterazine. The amounts of luciferase used for the measurement of each point luciferase A, 170 LU luciferase B, 190 LU luciferase C, 210 LU luciferase L, 210 LU. From Shimomura et al., 2001.

Fig. 4.5.5 Effect of pH on the luminescence of coelenterazine catalyzed by Periphylla luciferases A, B and C, and on the stability of the luciferases. The effect on light intensity (solid lines) was measured in 3 ml of 50 mM phosphate buffers, pH 4.1-7.25, and 50 mM Tris-HCl buffers, pH 7.1-9.7, all containing 1 M NaCl, 0.025% BSA, and 0.3 pM coelenterazine. To measure the stability (dotted lines), a luciferase sample (5 pi) was left standing for 30 min at room temperature in 0.1 ml of a buffer solution containing 1 M NaCl and 0.025% BSA and having a pH to be tested, and then luciferase activity in 10 pi of the solution was measured in 3 ml of 20 mM Tris-HCl, pH 7.8, containing 1M NaCl, 0.05% BSA, and 0.3 pM coelenterazine at 24°C. The amounts of luciferases used for measuring each point were luciferase A, 150 LU luciferases B and C, 170 LU. One LU = 5.5 x 108 quanta/s. From Shimomura etal., 2001.

Fig. 4.8.4 Effect of pH on the light intensity of the Ca2+-triggered luminescence of mnemiopsin-1 (o), mnemiopsin-2 ( ), and berovin (A). From Ward and Seliger, 1974b, with permission from the American Chemical Society.

Fig. 6.1.7 Effect of pH on the initial light intensity and total light of Latia bioluminescence reaction in the presence of the purple protein, in 50 mM sodium phosphate buffer solutions having various pH values at 25°C (Shimomura et al., 1966b).

Fig. 6.3.6 Effects of salt concentration (left panel) and pH (right panel) on the initial light intensity emitted from the homogenate of the Symplectoteuthis oualaniensis light organ. The salt effect was tested in 50 mM Tris-HCl, pH 7.2, and the pH effect in the various buffers containing 0.5MKC1 or NaCl. From Tsuji and Leisman, 1981.

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