Moritz Friebel

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The absorption coefficient mu(a), scattering coefficient mu(s), and anisotropy factor g of diluted and undiluted human blood (hematocrit 0.84 and 42.1%) are determined under flow conditions in the wavelength range 250 to 1100 nm, covering the absorption bands of hemoglobin. These values are obtained by high precision integrating sphere measurements in(More)
Visible and near-infrared (NIR) integrating sphere spectroscopy and chemometric multivariate linear regression were applied to determine hematocrit (HCT) and oxygen saturation (SatO2) of circulating human blood. Diffuse transmission, total transmission, and diffuse reflectance were measured and the partial least squares method (PLS) was used for calibration(More)
The real part of the complex refractive index of oxygenated native hemoglobin solutions dependent on concentration was determined in the wavelength range 250 to 1100 nm by Fresnel reflectance measurements. The hemoglobin solution was produced by physical hemolysis of human erythrocytes followed by ultracentrifugation and filtration. A model function is(More)
The intrinsic optical parameters absorption coefficient mu(a), scattering coefficient micros, anisotropy factor g, and effective scattering coefficient micros were determined for human red blood cell (RBC) suspensions of hematocrit 33.2% dependent on the oxygen saturation (SAT O(2)) in the wavelength range 250 to 2,000 nm, including the range above 1,100(More)
1. Arteriolar diameter in the resting rat spinotrapezius muscle was studied by intravital video microscopy before and after blockade of the L-arginine-EDRF (NG-nitro-L-arginine, L-NNA) or the cyclo-oxygenase-prostacyclin (indomethacin) pathway. Blockade of either pathway leads to a decrease of arteriolar diameter of 25-40%, while the combined blockade of(More)
The optical parameters absorption coefficient, scattering coefficient, and the anisotropy factor of platelets (PLTs) suspended in plasma and cell-free blood plasma are determined by measuring the diffuse reflectance, total and diffuse transmission, and subsequently by inverse Monte Carlo simulation. Furthermore, the optical behavior of PLTs and red blood(More)
The absorption coefficient, scattering coefficient, and effective scattering phase function of human red blood cells (RBCs) in saline solution were determined for eight different hematocrits (Hcts) between 0.84% and 42.1% in the wavelength range of 250-1100 nm using integrating sphere measurements and inverse Monte Carlo simulation. To allow for biological(More)
The complex refractive index of highly concentrated hemoglobin solutions as they appear in red blood cells are determined in the wavelength range of 250 to 1100 nm using transmittance and Fresnel reflectance measurements. The determined real parts of the refractive indices are on average 0.02 units higher than the values found in the literature. The(More)
The intrinsic optical parameters-absorption coefficient mua, scattering coefficient mus, anisotropy factor g, and effective scattering coefficient mus'--are determined for human red blood cells of hematocrit 42.1% dependent on the shear rate in the wavelength range 250 to 1100 nm. Integrating sphere measurements of light transmittance and reflectance in(More)
Aesthetic restorations require dental restorative materials to have optical properties very similar to those of the teeth. A method is developed to this end to determine the optical parameters absorption coefficient mu(a), scattering coefficient mu(s), anisotropy factor g, and effective scattering coefficient mu(s) (') of dental restorative materials. The(More)