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Biomedical subjects

H Rettig

Publications and source records attributed to H Rettig.

At least 37 records · Page 2Linked to original sources
PubMed1979

[The use of carbon as manufacturing material of endoprotheses (author's transl)].

According to the present stage of technology, arthroplasties have a change of only short-term to medium-term success quotas despite good initial successes. Permanent healing is restricted because of possible loosening of the prostheses. Even clinically silent loosenings will ultimately lead to failures, either by progressive degeneration of the bones at the supporting points of the prosthesis or through breakage of the stem of the prostheses. Attempts to overcome such difficulties by changing the shape of the prostheses, remain unsuccessful. The material employed in the construction of the prosthesis is certainly of some importance in this connection. Carbon has been known for a long time as a well-tolerated material in implant surgery. Carbon is indeed distinguished by high biocompatibility. The development of new carbons based on graphite which considerably improve its physical properties, has enabled the manufacture of endoprostheses made from carbon. Studies have proved that this substance is nontoxic. There are also no immunological reactions. Abrasion is low, and the abraded particles do not produce any severe inflammatory reactions. Hence, prostheses made from carbon can be employed as combination constructions, using suitable types of carbon in accordance with the required functions.

Biocompatible Materials↗
PubMed1978

Electronic monitoring of events within dynamic particulate beds: conductance and capacitance measurements.

Methods for monitoring mechanical events occurring within particulate solids systems in a dynamic state are described. The electrical conductance and capacitance characteristics of such systems, as they relate to the degree of bed dilation or expansion, extent of interparticulate contact, and intensity of particle motion, were studied and are discussed. To establish the potential of this approach, harmonically vibrated beds of monodispersed conducting spheres were used. A technique, based on the frequency modulation of standard FM broadcast frequency carrier signals, was developed to measure low and high frequency fluctuations in bed capacitance. The electrical conductance of these systems also was determined by both voltage drop and current flow methods. The experimental techniques developed are broadly applicable to various materials and modes of agitation or flow. They permit the evaluation of the time courses of both bed dilation and particle motion which, in turn, are known to determine of modify critically powder flow and mixing behavior.

Chemistry, Pharmaceutical↗
PubMed1977

[Mechanical properties of carbon as implant material in orthopedic surgery (author's transl)].

Among others material problems are come to the fore in endoprothetic with growing biochemical knowledge, also because of the realisation that in different parts of the same prothesis functionally different mechanical demands must be set. Technological progress in carbon production has lead to the development of a spectrum of different carbon specialities with various mechanical properties. In orthopaedic surgery of endoprothetic high strengh isotropic carbon, impregnated carbon and fibrereinforced carbon-carbon-composites are of particular interest, because of their physical properties and unchanged favourable chemical and biological properties of carbon. Thereby it is on one side a question of carbon material with extraordinary tribological qualities, on the other side of carbons with nearly isoelastic behaviour towards the bone, respectively with equal quotient of breaking strength and young's modulus. Therefore in future the manufacture of components with functional approbiate material using the same basic material carbon seems to be possible for the production of endoprothesis with different working parts.

Biomechanical Phenomena↗
PubMed1976

[Knee joint prosthesis with the geomedic knee joint (author's transl)].

Thirty-one cases of plastic knee joint operations were reported. Twenty-one patients were treated with the geomedic knee. The advantage of this joint is that only a small amount of bone must be sacraficed. The range of movement is better than that with a complete knee prosthesis with axis.

Aged↗
PubMed1975

[Effectiveness of thromboembolic prophylaxis in major hip surgery with low doses of heparin using the radiofibrinogen test (author's transl)].

The radiofibrinogentest was applied for early diagnosis of deep vein thrombosis (DVT) in 40 patients with major hip joint operations. A high dosage of Calciumdepotheparin (3 X 1 200 IU/10 kg) administered from the evening of the first postoperative day, proved to be a better prophylaxis of DVT in this kind of operation than a low dosage of heparin that administration was started preoperatively.

Female↗
PubMed1975

[Studies on the quantification of air in the process of silage making].

On the basis of model concepts on physical gas exchange a technique was developed for studying the complex interrelationships existing between the characteristics indicating the suitability of a particular material for ensilage and the specific local conditions for silage making at the farm and in a silo. (degree of anaerobic conditions). Conclusions were drawn as to quantitative relations existing between the thickness of the marginal layers of a silage stack that are subject to losses and the compaction of the silage material and the sealing of the silage top during the periods of filling and storage. On the basis of these considerations limits are given for minimum filling of a silo per day of ensilage as depending on the compactness of the consolidated fresh or wilted silage material. Data are given for silage losses at the edged of the silage stack.

Agriculture↗