Recherches sur l'absorption et la dispersion de la lumiere par.

Thesis (doctoral)--

The absorption spectra of solutions of certain salts of cobalt, nickel, copper, iron, chromium, neodymium, praseodymium, and erbium in water, methyl alcohol, ethyl alcohol, and acetone, and in mixtures of water with the other solvents.

"A continuation of the work of Jones and Uhler on the absorption spectra of solutions (Carnegie publication no. 60)" cf. Pref.

Optics and Optoelectronics of Two-dimensional Semiconducting Monolayers and Heterostructures

Thesis (Ph.D.)--University of Washington, 2016-06

Developments in the Theory of X-ray Absorption and Compton Scattering.

Thesis (Ph.D.)--University of Washington, 2016-06

Causes of variability in light absorption by particles in snow at sites in Idaho and Utah.

This file accompanies “NAmer2014SnowBC_Dohertyetal_v1.xlsx”, which contains data on black carbon (BC) and other light-absorbing particles in snow in Utah and Idaho, for samples collected January-March 2014 in Jan/Feb 2013 and 2014 in Utah. Data are available as an Excel file with headers, or as a comma-separated data file, with no headers. There is one entry per layer of snow sampled. All entries (other than column titles in the .xlsx) are numeric. Detailed information on our measurements can be found in a series of publications, as given below.  Description of the instrument and method used to make the measurements: Grenfell, T. C., S. J. Doherty, A. D. Clarke, and S. G. Warren, Spectrophotometric determination of absorptive impurities in snow, Appl. Opt., 50(14), pp.2037-2048, 2011.  Summary and discussion of dataset “NAmer2014SnowBC_Dohertyetal.xlsx”, including maps of sample locations: Doherty, S. J., D. A. Hegg, P. K. Quinn, J. E. Johnson, J. P. Schwarz, C. Dang and S. G. Warren, Causes of variability in light absorption by particles in snow at sites in Idaho and Utah, J. Geophys. Res. Atmos., 121, doi:10.1002/2015JD024375, 2016. Note that the measurement and analysis techniques used to produce these data were also used in a broad Arctic survey (2006-2010) of BC and other light-absorbing particles snow, as reported here: Doherty, S. J., S. G. Warren, T. C. Grenfell, A. D. Clarke, and R. E. Brandt: Light-absorbing impurities in Arctic snow, Atmos. Chem. Phys., 10, 11647-11680, doi:10.5194/acp-10-11647-2010, 2010. http://www.atmos-chem-phys.net/10/11647/2010/acp-10-11647-2010.html

Diffusion modeling of percutaneous absorption kinetics: 3. Variable diffusion and partition coefficients, consequences for stratum corneum depth profiles and desorption kinetics

Stratum corneum (SC) desorption experiments have yielded higher calculated steady-state fluxes than those obtained by epidermal penetration studies. A possible explanation of this result is a variable diffusion or partition coefficient across the SC. We therefore developed the diffusion model for percutaneous penetration and desorption to study the effects of either a variable diffusion coefficient or variable partition coefficient in the SC over the diffusion path length. Steady-state flux, lag time, and mean desorption time were obtained from Laplace domain solutions. Numerical inversion of the Laplace domain solutions was used for simulations of solute concentration-distance and amount penetrated (desorbed)-time profiles. Diffusion and partition coefficients heterogeneity were examined using six different models. The effect of heterogeneity on predicted flux from desorption studies was compared with that obtained in permeation studies. Partition coefficient heterogeneity had a more profound effect on predicted fluxes than diffusion coefficient heterogeneity. Concentration-distance profiles show even larger dependence on heterogeneity, which is consistent with experimental tape-stripping data reported for clobetasol propionate and other solutes. The clobetasol propionate tape-stripping data were most consistent with the partition coefficient decreasing exponentially for half the SC and then becoming a constant for the remaining SC. (C) 2004 Wiley-Liss, Inc.

Using a non-invasive stable isotope tracer to measure the absorption of water in humans

The development of solutions that prevent dehydration or promote adequate re-hydration play a vital role in preventing fatigue during exercise, however, the methods commonly used to assess the hydration ability of such solutions are invasive and often assess the components of absorption separately. This paper describes using a non-invasive deuterium tracer technique that assesses gastric emptying and intestinal absorption simultaneously to evaluate the uptake of water during rest and exercise. The kinetics of absorption are further examined by mathematical modelling of the data generated. For the rest group, 0.05 g/kg of body weight of deuterium, contained in gelatine capsules, was ingested with ordinary tap water and saliva samples were collected every 5 min for one hour while the subject remained seated. The deuterium was administered as above for the exercise group but sample collection was during one hour of exercise on a treadmill at 55% of the subject's maximum heart rate. The enrichment data for each subject were mathematically modelled and the parameters obtained were compared across groups using an independent samples t-test. Compared with the rest condition, the exercise group showed delayed absorption of water as indicated by significant differences for the modelling parameters t(2), t(1/2), maximum absorption rate and solution absorption amount at t(1). Labelling with a deuterium tracer is a good measure of the relative rate ingested fluids are absorbed by the body. Mathematical modelling of the data generates rates of maximum absorption and allows calculation of the percentage of the solution that is absorbed at any given time during the testing period. Copyright (C) 2004 John Wiley Sons, Ltd.

Investigation of in vitro transdermal absorption of fentanyl from patches placed on skin samples obtained from various anatomic regions of dogs

Objective-To investigate in vitro transdermal absorption of fentanyl from patches through skin samples obtained from various anatomic regions of dogs. Sample Population-Skin samples from 5 Greyhounds. Procedure-Skin samples from the dogs' thoracic, neck, and groin regions were collected postmortem and frozen. After samples were thawed, circular sections were cut and placed in Franz-type diffusion cells in a water bath (32degreesC). A commercial fentanyl patch, attached to an acetate strip with a circular hole, was applied to each skin sample. Cellulose strips were used as control membranes. Samples of receptor fluid in the diffusion cells were collected at intervals for 48 hours, and fentanyl concentrations were analyzed by use of high-performance liquid chromatography. Results-Mean +/- SD release rate of fentanyl from the patch, defined by its absorption rate through the non-rate-limiting cellulose membrane, was linear during the first 8 hours (2.01 +/- 0.05 pg/cm(2) of cellulose membrane/h) and then decreased. Fentanyl passed through skin from the groin region at a faster rate and with a significantly shorter lag time, compared with findings in neck or thoracic skin samples. Conclusions and Clinical Relevance-In vitro, fentanyl from a patch was absorbed more quickly and to a greater extent through skin collected from the groin region of dogs, compared with skin samples from the thoracic and neck regions. Placement of fentanyl patches in the groin region of dogs may decrease the lag time to achieve analgesia perioperatively; however, in vivo studies are necessary to confirm these findings.

The effect of region of application on absorption of ethanol and hexanol through canine skin

The effect of region of application on the percutaneous penetration of solutes with differing lipophilicity was investigated in canine skin. Skin from the thorax, neck, back, groin, and axilla regions was harvested from Greyhound dogs and placed in Franz-type diffusion cells. Radiolabelled (C-14) ethanol (Log P 0.19) or hexanol (Log P 1.94) was applied to each skin section for a total of 5 h. The permeability coefficient (k(P), cm h(-1)) and residue of alcohol remaining in the skin were significantly (P = 0.001) higher for hexanol compared to ethanol. In contrast, ethanol had a far greater maximum flux (J(max), mol (cm(2))(-1) h(-1)) than hexanol (P = 0.001). A comparison of regional differences shows the k(P) and Jmax for ethanol in the groin was significantly lower (P = 0.035) than the back. The k(P) and Jmax for hexanol were significantly higher (P = 0.001) in the axilla than the other four skin sites. An understanding of factors influencing percutaneous drug movement is important when formulating topical preparations for the dog. (C) 2003 Elsevier Ltd. All rights reserved.