Absorption Probes

Raksi F, Wilson K R, Jiang Z, Iklef A, Cote C Y and Kieffer J-C 1996 Ultrafast x-ray absorption probing of a chemical reaction J. Chem. Phys. 104 6066-99... 

The excellent agreement between the TSC and P1A results has two implications. First, since the TSC method probes the product of mobility and carrier density, while the P1A probes only the carrier density, there seems to be no dominant influence of temperature on the carrier mobility. This was also found in other conjugated polymers like /ra/ry-polyacetylene [19, 36]. Second, photoconductivity (observed via the thermal release of photoexcited and trapped earners) and photo-induced absorption probe the same charged entity [36, 37J. 

Mendelsohn, R. and R.W. Van Holten. 1979. Zeaxanthin ([3R,3 R]-beta, beta-carotene-3 -diol) as a resonance Raman and visible absorption probe of membrane structure. Biophys. J. 27 221-235. 

Absorption spectra, 23 3 of fats and oils, 10 822-823 of polymethine dyes, 20 506-512 Absorption spectroscopy, infrared reflection, 24 114-116 Absorption towers, in sulfuric acid manufacture, 23 779 Absorptive probes, 11 150 ABS polymers, 10 205-207. See also ABS (acrylonitrile-butadiene-styrene) materials... 

Direct determination of portal blood flow rate is difficult and would generally require placement of an electronic flow probe in each animal. However the technique proposed by Hoffman et al. utilised tritiated water as an absorption probe (i.e. internal standard) [89], By dosing and sampling drug/ absorption probe concurrently, factors such as variable portal blood flow rate are normalised between experiments. 

Hoffman DJ, Seifert T, Borre A and Nellans HN (1995) Method to Estimate the Rate and Extent of Intestinal-Absorption in Conscious Rats Using an Absorption Probe and Portal Blood-Sampling. Pharm Res 12 pp 889-894. 

Class 1-Thermal Methods. These utilize calorimeters [27,29], thermocouples or absorption probes [32,49], and the acoustic dilatometer [30,31]. 

Hoffman, D.J. Seifert, T. Borre, A. Nellans, H.N. Method to estimate the rate and extent of intestinal absorption in conscious rats using an absorption probe and portal blood sampling. Pharm.Res., 1995, 12, 889-894... 

In two-phase systems, however, where surfactant and water can partition between a fluid and a liquid phase, significant pressure effects occur. These effects were studied for AOT in ethane and propane by means of the absorption probe pyridine N-oxide and a fluorescence probe, ANS (8-anilino-l-naphthalenesulfonic acid) [20]. The UV absorbance of pyridine A-oxide is related to the interior polarity of reverse micelles, whereas the fluorescence behavior of ANS is an indicator of the freedom of motion of water molecules within reverse micelle water pools. In contrast to the blue-shift behavior of pyridine N-oxide, the emission maximum of ANS increases ( red shift ) as polarity and water motion around the molecule increase. At low pressures the interior polarity, degree of water motion, and absorbance intensity are all low for AOT reverse micelles in the fluid phase because only small amounts of surfactant and water are in solution. As pressure increases, polarity, intensity, and water motion all increase rapidly as large amounts of surfactant and water partition to the fluid phase. The data indicate that the surfactant partitions ahead of the water thus there is a constant increase in size and fluidity of the reverse micelle water pools up to the one-phase point. An example of such behavior is shown in Fig. 4 for AOT in propane with a total fVo of 40. The change in the ANS emission maximum suggests a continuous increase in water mobility, which is due to increasing fVo in the propane phase, up to the one-phase point at 200 bar. 

FIGURE 7.2 Some polarity probes (absorption probes). 

C. Wang, S. Poliak, and M.M. Kappes, Molecular Excited States versus Collective Electronic Oscillations Optical Absorption Probes of Na4 and Nas , Chem. Phys. Lett. 166, 26 (1990). 

Furthermore, using methyl orange (MO) and methylene blue (MB) as absorption probes, the micropolarity of the microemulsion system was investigated by UV-Vis spectroscopy [11]. The results demonstrated that micropolarity increased with the addition of IL only before the IL pools were formed. Once the IL was saturated for the solubilizing ability of the EO units and began to form cores of the microemulsions, the micropolarity became relatively constant. 

Among the absorption probes investigated, the 2,6-diphenyl-4-(2,4,6-triphenyl-l-pyridino)phenoxide is claimed to be the most sensitive to solvent... 

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