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To quantify the impact of forest management practices and tree growth rate on the potential uses of Douglas-fir wood, nine physico-mechanical properties were studied on more than 1250 standardized clear specimens. These were collected from trees cut in 11 even-aged stands (six trees per stand) located in Wallonia (southern Belgium). Stands were 40 to 69 years old, and mean tree girth was ca. 150 cm. Mean ring width of the 66 trees ranged from 3 to more than 7 mm. Statistical analysis showed significant but weak effects of ring width on the studied properties. Considered jointly, mean ring width and cambial age of the test specimens only explained 28% to 40% of the variability of their properties. Also, when ring width increases, these properties display higher decreases in juvenile wood than in mature wood. From a technological standpoint, maintaining mean ring width under 4 mm in juvenile wood and 6 mm in mature wood should accommodate all potential uses of Douglas-fir wood. However, considering that density appeared to be the main driver of wood properties, our results and the literature corroborate the importance of genetic selection as a complement to silvicultural measures to improve or guarantee the technological properties of Douglas-fir wood. Key words: Douglas-fir, mechanical properties, ring width, clear wood specimen, wood quality. Afin de quantifier l'impact des modalites de gestion sylvicole, et donc de la vitesse de croissance des arbres sur les potentialites d'usage du Douglas, neuf proprietes physico-mecaniques ont ete mesurees sur plus de 1250 eprouvettes standardisees. Celles-ci sont issues d'arbres preleves dans 11 peuplements equiennes (six arbres/peuplement) situes en Wallonie (sud de la Belgique). L'age des peuplements varie de 40 a 69 ans, tandis que la circonference moyenne des arbres avoisine 150 cm. La largeur moyenne des cernes des 66 arbres varie ainsi de 3 a plus de 7 mm. Les analyses statistiques ont montre des effets significatifs mais faibles de la largeur des cernes sur les proprietes etudiees. Consideres ensemble, la largeur des cernes et l'age cambial des eprouvettes n'expliquent que 28 a 40 % de la variabilite des proprietes etudiees. D'autre part, lorsque la largeur des cernes augmente, ces proprietes diminuent davantage dans le bois juvenile que dans le bois mature. D'un point de vue technologique, limiter la largeur moyenne des cernes a 4 et 6 mm, respectivement, dans le bois juvenile et mature, permet de maintenir les meilleures potentialites d'usages du bois. Cependant, etant donne que la densite apparait comme le principal determinant des proprietes mecaniques, nos resultats et la litterature corroborent l'importance de la selection genetique en complement de la gestion sylvicole en vue d'ameliorer ou de garantir les proprietes technologiques du bois de Douglas. Mots-cles: Douglas, proprietes mecaniques, largeur de cerne, eprouvettes sans defaut, qualite du bois., Introduction Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) was introduced into the Ardenne region of Belgium in 1871 and currently covers around 23 000 ha, i.e., slightly less than 10% of the [...]

Experiments were conducted to quantify the effect of several variables on the mortality of insects exposed to an anoxic treatment in order to generate a model linking mortality to these variables. This study aims to explore the possible interest of using such a model to determine the characteristics of treatment (especially duration) needed to guarantee insect mortality with a given level of probability. Trials were performed on Hylotrupes bajulus larvae, which is a widespread species known for its high tolerance to anoxic conditions. The studied variables are the initial mass of the larvae, the treatment temperature (21, 30 and 40 °C), the treatment duration (four durations for each temperature tested) and whether the larva is held in wood or in a petri dish (directly exposed to anoxic atmosphere) during the experiment. It was found that, while the last variable is not correlated with mortality, treatment duration and temperature are significantly and positively correlated with it. Larvae with higher body mass were also shown to have a better resistance to the treatment. Based on these results, a model including insect initial mass, treatment temperature and duration, together with the interaction between these two variables, was determined. This relatively simple model appeared to be a useful tool in overcoming the difficulty in defining the modalities for anoxic treatment in order to reach a given level of mortality. [ABSTRACT FROM AUTHOR]

Two glass and rock wools (Saint-Gobain) were compared with a glass microfibre (Johns Manville 100) and a chrysotile fibre in order to determine the retention of fibres in different parts of the lung and the risk of fibrous and tumorous lesions forming. The rats were exposed in dust chambers containing equal respirable mass concentrations (5 mg m of these materials. After 12 and 24 months of exposure followed by various periods for lesion development, fibre retention was analysed and the tissues were examined. The numbers of fibres retained were 20–30 times greater for JM 100 and chrysotile than for SG glass wool and about 10 times higher for SG glass wool than for SG rock wool. Fibres which migrated into the lymph nodes were shorter than those in the lungs. During their period of residence in the lungs, the four types of fibre showed changes amounting to almost total disintegration in some cases. Under the conditions of the experiment, the noxious character of the SG glass and rock wools was very low. Only chrysotile produced a significant increase in pulmonary collagen. The tumour-inducing power of the glass and rock wools was practically non-existent. [ABSTRACT FROM PUBLISHER]

Laryngeal microsurgery has been performed using a CO2 laser since 1978. It is essential to conduct a strict phoniatric pre-operative examination and to ensure correct anesthesia. Results after 735 operations underline the advantages of this technique for the treatment of benign laryngeal lesions (diffuse papillomatosis, sessile polyps, granuloma), in phonosurgery (nodules, bundle edema, corditis) and in the repermeabilization of the laryngeal network (paralysis, stenosis, laryngeal edema).

The authors describe a microsurgical procedure for translaryngeal arytenoidectomy in bilateral vocal cord paralysis and relate their clinical experience. They consider this approach as very valuable in as much as a rather minimal surgical procedure will create a good airway while conserving a satisfactory vocal function.

The authors present one case of systemic lupus erythematosus associated with paralysis of the larynx and spontaneous expulsion of the arytenoid cartilage followed by healing. Two cases of chronic atrophic polychondritis are also presented, and the diagnostic and therapeutic criteria of the disease are discussed.

The aim of this research was to compare isolated ganglionic development in patients treated surgically for cancer of the larynx. This research included the cases of 232 patients operated on for laryngeal cancer and who underwent either total laryngectomy with or without conservation of the cricoid, or supra-glottal laryngectomy, or sub-glottal pharyngectomy. For the treatment of the ganglionic areas, there are six possibilities: --cobalt used in isolation; --uni- or bi-lateral cellulo-adenectomy; --uni- or bi-lateral curettage (a month apart); --curettage on one side, cellulo-adenectomy on the other. The results obtained were particularly significant as far as the N0 and regrouped N1 were concerned. The rate of ganglionic recurrence was 25 p. 100 for the N0 treated with cobalt and 6,5 p. 100 when surgery was carried out (cellulo-adenectomy or curettage). Also, curettage seems in N + cases to give better results : 26 p. 100 recurrence in cases of cellulo-adenectomy for N0-N1 and 4 p. 100 only in cases of curettage. These results appear to justify on the spot histological examination followed by curettage in N + cases.

Facial paralyses in children may be grouped under headings displaying a certain amount of individuality. Chronologically, first to be described are neonatal facial paralyses. These are common and are nearly always cured within a few days. Some of these cases are due to the mastoid being crushed at birth with or without the use of forceps. The intra-osseous pathway of the facial nerve is then affected throughout its length. However, a cure is often spontaneous. When this desirable development does not take place within three months, the nerve should be freed by decompressive surgery. The special anatomy of the facial nerve in the new-born baby makes this a delicate operation. Later, in all stages of acute otitis, acute mastoiditis or chronic otitis, facial paralysis can be seen. Treatment depends on the stage reached by the otitis: paracentesis, mastoidectomy, various scraping procedures, and, of course, antibiotherapy. The other causes of facial paralysis in children are very much less common: a frigore or viral, traumatic, occur ring in the course of acute poliomyelitis, shingles or tumours of the middle ear. To these must be added exceptional causes such as vitamin D intoxication, idiopathic hypercalcaemia and certain haemopathies.

The action of high doses of cigarette smoke alone or combined with coal dust or acrolein was investigated in noninbred Sprague-Dawley rats. Inhalation occurred up to six sessions per day (Hamburg machine), the animals being subjected to a treatment with oxygen after each inhalation session to reduce the carbon monoxide level in the blood. The amount of tar found in the lungs depended on the number of inhalation sessions per day rather than on the total number of inhalations. Smoke inhalation caused emphysematous lesions, the extent of which depended on the total dose of smoke inhaled. No lung tumors were observed. Only a hyperplasia of the alveolar lining involving type II alveolar cells and, at a later stage, areas of metaplasia generally limited to the bronchial area were found. The association of coal dust with cigarette smoke did not alter the specific effects of smoke and resulted in effects peculiar to the action of dust: alveolitis of the macrophage type, fibrosis of the reticulin type, limited hyperplasia, and ciliated metaplasia. When smoke was combined with acrolein, the effects due to smoke were not appreciably altered.

When animals are exposed to cigarette smoke, the concentration of carbon monoxide in blood is rapidly increased, so that intensive inhalation tests cannot be carried out. A simple apparatus is described to expose Rats alternatively to cigarette smoke and to oxygen in order to reduce the concentration of carbon monoxide in the blood. This method makes it possible to increase the daily administration of smoke considerably; nevertheless, under such conditions, lung tumors were not observed.