Biomedical subjects

Jürgen Lenz

Publications and source records attributed to Jürgen Lenz.

3 recordsLinked to original sources

PubMed2006

Heterogeneous activation of the medial pterygoid muscle during simulated clenching.

The aim of this study was to investigate whether the medial pterygoid muscle shows differential activation under experimental conditions simulating force generation during jaw clenching. To answer this question, the electromyographic activity of the right medial pterygoid was recorded with two intramuscular electrodes placed in an anterior and posterior muscle region, respectively. Intraoral force transfer and force measurement were achieved by a central bearing pin device equipped with strain gauges. The activity distribution in the muscle was recorded in a central mandibular position during generation of eight different force vectors at a constant amount of force (F=150 N). The investigated muscle regions showed different amounts of EMG activity. The relative intensity of the activation in the two regions changed depending on the task. In other words, the muscle regions demonstrated heterogeneous changes of the EMG pattern for various motor tasks. The results indicate a heterogeneous activation of the medial pterygoid muscle under test conditions simulating force generation during clenching. This muscle behaviour might offer an explanatory model for the therapeutic effects of oral splints.

Adult↗

PubMed2005

Solid-state fermentation--are there any biotechnological advantages?

Solid-state fermentation (SSF) has developed in eastern countries over many centuries, and has enjoyed broad application in these regions to date. By contrast, in western countries the technique had to compete with classical submerged fermentation and, because of the increasing pressure of rationalisation and standardisation, it has been widely superseded by classical submerged fermentation since the 1940s. This is mainly because of problems in engineering that appear when scaling up this technique. However, there are several advantages of SSF, for example high productivities, extended stability of products and low production costs, which say much about such an intensive biotechnological application. With increasing progress and application of rational methods in engineering, SSF will achieve higher levels in standardisation and reproducibility in the future. This can make SSF the preferred technique for special fields of application such as the production of enzymes and food.

Bacteria↗

PubMed2005

Activity patterns of the masticatory muscles during feedback-controlled simulated clenching activities.

In 10 normal subjects, the electromyographic (EMG) activities of the masseter, anterior and posterior temporalis, medial pterygoid, inferior lateral pterygoid, as well as the anterior digastric, were bilaterally recorded during clenching with various resulting force vectors. The intraoral force transfer was achieved with a three-component force transducer. The direction and magnitude of the force vectors were controlled by visual feedback. The goal of the study was to investigate how various clenching directions at constant magnitude of force influence the EMG activity in the masticatory muscles during gradual increase of the horizontal force component. Depending on the force direction and the individual muscle, an increase or decrease of activity was observed during clenching with increasing horizontal force components at constant magnitude of force. The inferior lateral pterygoid exhibited the highest activation (about 80% of maximal voluntary clenching) of all masticatory muscles. The medial pterygoid showed the greatest range of variation in activation behavior, and it was the most active muscle in relation to all clenching directions. In conclusion, the results show that with growing horizontal force components at constant magnitude of force, all muscles demonstrated an increase or decrease of activity in several clenching directions.

Adult↗