Accurate diffuse reflection measurements in the infrared spectral range

A sphere arrangement for directional-hemispherical reflectance measurements in the 1-15-microm wavelength range is tested for its accuracy. Comparative measurements with the fundamental PTB sphere reflectometer in the overlapping spectral range between 1.0 and 1.1 microm indicate no systematic measurement uncertainties of the new device. The uncertainty of the reflectance measured by it is therefrom deduced to be +/-0.01 for the 1-5.6-microm wavelength range.

Computer-controlled gonioreflectometer for the measurement of spectral reflection characteristics

A computer-controlled apparatus-the gonioreflectometer-is described, which was designed and manufactured at the Physikalisch-Technische Bundesanstalt. It enables the spectral radiance coefficient to be measured for all relevant angles of incidence and viewing. From basic considerations about the relationship between reflection characteristics it is shown that, e.g., the reflectance or the radiance factor for standardized geometries can be calculated from the measured radiance coefficient. This makes it required instrumentation for the calibration of reflection standards.

[Treatment of patients with gallstones with chenodeoxycholic acid (author's transl)]

24 patients with cholesterol gallstones were treated with chenodeoxycholic acid. In 7 out of 10 patients the follow-up showed complete dissolution of the gallstones after 7 to 18 months of treatment with 1 g of chenodeoxycholic acid daily. Two patients with biliary duct concrements had to be operated, in a third patient no change could be observed after treatment for 17 months. A transient increase of the transaminase GOT was seen in four patients. There were no changes of serum cholesterol and triglyceride levels. 14 patients had chologenic diarrhoea lasting only a few days. Toxic side effects indisputably due to chenodeoxycholic acid therapy have not been seen so far.

[Influence of ornithin-alpha-ketoglutaric acid on fatmetabolism in patients with cirrhosis of the liver (author's transl)]

Formation of endogenous toxins through protein metabolism and detoxification through liver are described. In chronic hepatic insufficiency (cirrhosis of the liver), with failure of liver metabolism, levels of endogenous toxins in plasma and tissue, i.e. ammonia, phenol-derivatives and free fatty acids, rise. Plasma levels of ammonia and free fatty acids are both dependent on the Krebs cycle. This interaction and mutual dependance was examined clinically through application of amino acids that lower plasma ammonia level. Di-L(+)ornithin-alpha-ketoglutaric acid was able to lower ammonia levels in patients with liver cirrhosis. The difference between pre- and postinfusion levels of ammonia was significant, this corresponds to the observations of other authors. In addition we found a fall in levels of free fatty acids, triglycerides, and cholesterol. This effect on fatmetabolism was also observed in patients with no evidence of incipient or manifest hepatic insufficiency. The biochemical basis and the clinical implications of these findings are discussed.

Requirements for reflection standards and the measurement of their reflection values

The standards necessary for transferring the reflection scale must meet certain requirements. First, the present paper discusses the question of how far these requirements are met by the materials now used for realizing the reflection standards. Then the instrumentation is described that was developed in the Physikalisch-Technische Bundesanstalt for measuring the spectral radiance factor beta(lambda) for the d/O and 45/0 geometries and in principle also for the inverse geometries. How these measurements are made so that the values obtained for a material standard are related to the perfect reflecting diffuser as the primary standard is discussed.