Inclusion characterization in a scattering slab with time-resolved transmittance measurements: perturbation analysis

Abstract

A procedure for the time-domain optical characterization of an inclusion in a scattering slab is investigated theoretically and experimentally. The method relies on the measurement of a contrast function, which is defined as the time-dependent relative change in the transmitted signal resulting from the presence of the inclusion. Analytical expressions for the contrast functions of absorptive and diffusive inclusions are obtained through a perturbation solution of the diffusion equation. This procedure is used successfully to determine the optical properties of absorptive, diffusive, and mixed inclusions located at midplane in a scattering slab by use of time-resolved transmittance measurements.

Analysis of ICCD time-gated images through turbid media using a perturbative model

“…In particular, the fitting procedure does not distinguish between the inclusion in front of the input beam (z inc =1) and in front of the exit plane (z inc =4). The same result has been observed using a perturbative model based on the diffusion equation [10]. Using a standard Pentium™ personal computer, the fit takes about 100 ms for each pixel.…”

“…Now let us consider the analysis of the experimental data with the perturbative model previously described. Perturbative models have been already used, especially in a coaxial geometry [8] [10]. Therefore, the first step has been to check the capability of our imaging system to give the same results in such a configuration.…”

Analytical calculation of the mean time spent by photons inside an absorptive inclusion embedded in a highly scattering medium

“…7 This kind of behavior at small ⌬t is not explained by the standard diffusion model of time-resolved contrast functions as discussed, for example, by Morin, et al 11 Researchers using diffusion models generally introduce an ad hoc correction that is equivalent to one extra RW step. 11,12 To further test the accuracy of the RW approach for estimates of absorptive contrast, we look at a correction factor for nonlocalized absorbing inclusions. We use the results of MC simulations and experiments that provide the time-integrated ͑CW͒ values of the mean time spent by photons inside an absorptive inclusion.…”

A thermodynamic study of the cyclodextrin-UC781 inclusion complex using a HPLC method

“…The thermodynamic properties are important for the understanding and processing method optimization of βCD complex development. Several physical–chemical methods have been used to characterize the thermodynamic properties of inclusion complexes including UV spectroscopy [16, 17], NMR spectroscopy [17], as well as liquid chromatographic methods, such as thin layer chromatography [18] and high performance liquid chromatography (or High Pressure Liquid Chromatography HPLC) system [19, 20]. The difference on retention characteristics between complexed drug and neat drug [21, 22] can be used to evaluate their thermodynamic properties.…”