Noninvasive Oxygen Monitoring in Three-Dimensional Tissue Cultures Under Static and Dynamic Culture Conditions.

We present a new method for noninvasive real-time oxygen measurement inside three-dimensional tissue-engineered cell constructs in static and dynamic culture settings in a laminar flow bioreactor. The OPAL system (optical oxygen measurement system) determines the oxygen-dependent phosphorescence lifetime of spherical microprobes and uses a two-frequency phase-modulation technique, which fades out the interference of background fluorescence from the cell carrier and culture medium. Higher cell densities in the centrum of the scaffolds correlated with lower values of oxygen concentration obtained with the OPAL system. When scaffolds were placed in the bioreactor, higher oxygen values were measured compared to statically cultured scaffolds in a Petri dish, which were significantly different at day 1-3 of culture. This technique allows the use of signal-weak microprobes in biological environments and monitors the culture process inside a bioreactor.

[The thoracic radiologic significance of the width of the azygous vein and its correlation with right atrial blood pressure]. / Die thoraxradiologische Bedeutung der Weite der V. azygos und deren Beziehung zum rechtsatrialen Blutdruck.

The widths of the azygos vein were measured in 150 patients and correlated with the pressure in the right heart-atrium. We found a significant logarithmic correlation (r = 0.8) between the two parameters. Radiologic measurement of the width of V. azygos in chest radiographs or CT is useful to evaluate the function of the right heart.

[Pulmonary arteriovenous fistulas in Osler's disease]. / Pulmonale arteriovenöse Gefässfisteln bei M. Osler.

In a retrospective study over a period of 10 years we found 16 patients with Osler's disease and associated pulmonary arteriovenous fistulas in the hospital of the University of Heidelberg and the Thoraxklinik Heidelberg-Rohrbach. We report about the radiologic diagnostic findings and the clinical manifestations of this defined pulmonary malformation. Radiologic findings are round or oval lobulated homogeneous masses. The size ranges from < 1 to several centimeters in diameter, most fistulas were located in the lower lobes. Feeding and draining vessels can be identified frequently on plain radiographs or tomograms/CT. Best procedure to recognize these malformations is the selective pulmonary arterial angiography.

Symmetry theorems on the forward and backward scattering Mueller matrices for light scattering from a nonspherical dielectric scatterer.

The symmetry theorems on the complete forward and backward scattering Mueller matrices for light scattering from a single dielectric scatterer (as opposed to an ensemble of scatterers) are systematically and thoroughly analyzed. Symmetry operations considered include discrete rotations about the incident direction and mirror planes not coinciding with the scattering plane. For forward scattering we find sixteen different symmetry shapes (not including the totally asymmetric one), which may be classified into five symmetry classes, with identical reductions in the forward scattering matrices for all symmetry shapes that fall into the same symmetry class. For backward scattering we find only four different symmetry shapes, which may be classified into only two symmetry classes. The forward scattering symmetry theorems also lead to a symmetry theorem on the total extinction cross section. Based on the conclusions of this work it should be possible to design quick and nondestructive methods for the identification of certain small objects, when suitable partial information about the objects to be identified is already available. A promising practical example is given.

Mueller matrix calculations for dielectric cubes: comparison with experiments.

A new resolvent kernel method is presented for solving the problem of electromagnetic scattering from irregular homogeneous particles. This method has an advantage over other methods in that an integrodifferential equation with a simple initial condition is solved to give a resolvent kernel matrix for a complete range of refractive indices for a fixed particle size. This matrix can then be used to calculate both near and far fields for any incident wave. Results are presented for a homogeneous cube in random orientation and compared with microwave analog measurements.