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Biomedical subjects

J Payan

Publications and source records attributed to J Payan.

10 recordsLinked to original sources
PubMed1992

Neuropathy in chronic obstructive pulmonary disease: a multicentre electrophysiological and clinical study.

The incidence and type of neuropathy in patients with chronic obstructive pulmonary disease (COPD) were assessed. In a selected group of 89 patients, abnormal nerve conduction studies were found in 44%. Electrophysiological signs of a generalized peripheral neuropathy were found in 5-18%, depending on diagnostic criteria. Lesions which were thought to be due to compression or other forms of trauma were present in a further 24%. In the patients with peripheral neuropathy, the changes were distally predominant, affected mainly sensory fibres, and were consistent with an axonal type of neuropathy. There was a significant correlation between age and the incidence of peripheral neuropathy. Electrophysiological evidence of neuropathy was three times as common as clinical evidence. Much of the variation in the reported incidence of neuropathy in COPD is probably due to imprecise diagnostic criteria.

Adult↗
PubMed1979

Evaluation of alternative alloys to precious ceramic alloys. 1. Mechanical properties.

In the first part of this study, the microstructures and the mechanical properties of precious, semi-precious, and nonprecious dental casting alloys for the porcelain-baked-to-metal technique have been determined. The semi-precious alloys contained only 50% gold, and palladium, silver, and some base metals. The nonprecious alloys were of the nickel-chromium type. Discs and miniaturized tensile bars have been cast and tested either in the as cast condition, or after a simulation of the various porcelain bakes. Proof stress, ultimate tensile strength, elongation, and plastic stiffness have been measured and results compared by use of analyses of variance. The microstructure examination shows that the simulation of the porcelain bakes improves the homogeneity of the precious and semi-precious alloys. Simultaneously, the mechanical properties of the same alloys are also improved. One semi-precious alloy, still under development at the time of these tests, has its mechanical characteristics markedly downgraded by the thermal treatments. The nickel-chromium alloys exhibit the best range of mechanical properties for the porcelain-baked-to-metal technique, when considering the three most relevant properties: proof stress, plastic stiffness, and modulus of elasticity.

Chemical Phenomena↗
PubMed1977

[Comparative testing of various resins for model dies].

The value of resins for model dies is controversial. This objective study indicates that epoxy- and epimine resins may be successfully used as die materials, if certain measures are taken as a precaution. The resin should be centrifuged and a slight contraction of the material must be calculated into the chain of manufacture. The material should not be poured into hydrocolloid impressions, as the humidity of this impression material may interfere with the proper polymerization of the resin. A major inconvenience are the frequent formation of air bubbles on the angles of the preparation, and this in spite of the use of the vibrator.

Acrylic Resins↗
PubMed1975

[Attempt at a statistical analysis of the values of the free-way space measured on a sample of 54 patients].

The measurements of the free-way space (= distance between physiologic rest position and centric occlusion) vary according to the method used. In order to get a more distinct reference point, the authors suggest tattooing the Menton (lowest chin point) rather than the Pogonion (most anterior chin point). The free-way space measured in this study ranged from 0.5 to 8 mm. 75% of all cases examined revealed a free-way space between 1 and 2 mm and only 5% showed extreme values such as 0.5 and 8 mm. In contrast to Thompson, who believes that the vertical dimension of occlusion equals the vertical dimension in rest position minus 2 mm the results of this study are in agreement with the findings of those authors, who observed an individually great variation of the free-way space.

Cephalometry↗
PubMedDate not supplied

The blanket principle: a technical note.

Low-frequency attenuation of motor unit potentials may reveal abnormal complexity and instability of the motor unit. An ordinary concentric needle electrode is used, so the method bridges the gap between single-fiber and conventional electromyography.

Electromyography↗
PubMedDate not supplied

[The balanced hook].

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Dental Abutments↗