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Biomedical subjects

R Walther

Publications and source records attributed to R Walther.

4 recordsLinked to original sources

Citrate, a specific substrate for the isolation of Clostridium sphenoides.

With a medium containing citrate as the carbon and energy source, 10 clostridial strains were isolated from various mud samples. Characterization of these strains revealed that they all belonged to the same species, Clostridium sphenoides. Strains of this organism obtained from culture collections were also able to grow citrate, whereas 15 other clostridial species tested were not. Citrate was fermented by C. sphenoides to acetate, ethanol, carbon dioxide, and hydrogen. Experiments with stereospecifically 14C-labeled citrate indicated that citrate lyase was involved in citrate degradation.

Acetates

Evaluation of an integrated multi-media learning system.

Two teaching methods were compared: (1) the traditional way with textbooks, practical guidance, personal demonstration, and (2) an integrated multimedia system with text programme, slide-sound-show accompanying the experiment, and lecturer. Two samples of thirty-one students each were classified in twin groups by means of psychological tests. Both groups worked with the identical pretest/post-test and different training procedures. The integrated multi-media system produced highly significant more gain in the theoretical sphere, greater personal confidence, and lower experimental error. Furthermore positive attitude of the students towards the experiment was demonstrated. The improved performance was statistically proved by t-test and covariance analysis.

Audiovisual Aids