We present a comprehensive review of implementation and application of Laplace deep-leve1 transient spectroscopy (LDLTS). The various approaches that have been used previously for high-resolution DLTS are outlined and a detailed description is given of the preferred LDLTS method using Tikhonov regularization. The fundamental limitations are considered in relation to signal-to-noise ratios associated with the measurement and compared with what can be achieved in practice. The experimental requirements are discussed and state of the art performance quantified. The review then considers what has been achieved in terms of measurement and understanding of deep states in semiconductors through the use of LDLTS. Examples are given of the characterization of deep levels with very similar energies and emission rates and the extent to which LDLTS can be used to separate their properties. Within this context the factors causing inhomogeneous broadening of the carrier emission rate are considered. The higher resolution achievable with LDLTS enables the technique to be used in conjunction with uniaxial stress to lift the orientational degeneracy of deep states and so reveal the symmetry and in some cases the structural identification of defects. These issues are discussed at length and a range of defect states are considered as examples of what can be achieved in terms of the study of stress alignment and splitting. Finally the application of LDLTS to alloy systems is considered and ways shown in which the local environment of defects can be quantified.

General information on the propertiesCompound 3 was found to exhibit both thermochromic and solvatochromic properties. The UV-vis data reported here thus refer to compound 3 dissolved in THF or chloroform at 25 o C. Compound 1 does not fully dissolve metallic palladium on realistic timescales. It does however dissolve palladium nanoparticles formed during catalysis completely in a short time interval (typically 60 min) as established by ultracentrifugation and following the

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IntroductionPrevious studies have demonstrated the superior efficacy of a novel aerosol foam formulation of fixed combination calcipotriene 0.005% (Cal) and betamethasone dipropionate 0.064% (BD), compared with the ointment formulation. The aim of this study is to ascertain whether enhanced bioavailability of the active ingredients due to supersaturation and/or occlusive properties can explain the observed greater clinical efficacy.MethodsSolubility and evaporation experiments were conducted to examine the abilities of Cal/BD aerosol foam ingredients to create a supersaturated environment. Optical microscopy, Raman imaging and X-ray powder diffraction were used to examine the physical state of Cal and BD in the formulations after application, and determine whether a supersaturated state remained stable for clinically relevant time periods. In vitro skin penetration and ex vivo biomarker assays were conducted to compare the skin penetration and bioavailability of Cal and BD from the aerosol foam and ointment formulations, respectively. Occlusive properties were examined via transepidermal water loss.ResultsSolubility studies showed that Cal and BD solubility increased with increasing dimethyl ether (DME) content. Both active ingredients are completely dissolved in the final aerosol foam formulation. DME rapidly evaporates after spraying, and the amount was reduced to 0.5% of the initial amount after 2 min. This led to the formation of a supersaturated environment, where Cal and BD crystals were absent for at least 26 h after application. Cal/BD aerosol foam had significantly greater in vitro skin penetration and had increased bioavailability compared with Cal/BD ointment. Both formulations effectively occluded the skin.ConclusionA stable supersaturated solution of Cal/BD in the aerosol foam leads to increased bioavailability and explains the improved clinical effect when compared to the Cal/BD ointment.FundingThe studies included in the paper are all conducted by LEO Pharma A/S or CROs on behalf of LEO Pharma A/S.

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