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Bericht des Silikose-Forschungsinstituts der Bergbau Berufsgenossenschaft
d. Aerosol Science, 1975,Vol.6, p. 274. PergamonPress. Printedin Great Britain.
REPORT Bericht des Silikose-Forschungsinstituts der Bergbau Berufsgenossenschaft. 1973. pp. 125, 463, Bochum, Hunscheidstrasse 18, Germany. The 1972 report of the Silicosis Research Institute was reviewed in the d. Aerosol Sci. 5 (3), 321. The interest of the Medical Division in proteolytic enzymes continues; they contribute to chronic obstructive bronchitis through the release of debris of tissue and bacteria, a complicated spectrum of proteases and inhibitors being involved. Work has been carried out, using dogs, on the effect of the vagal reflex upon the ventilation-perfusion ratio; it is concluded that the vagal nerve has no influence and that gas regulation is probably centred on the alveolar regions. Studies of the mechanics of breathing furnish some interesting data on airway resistance in normal patients and those with obstruction and emphysema; there are diagrams of oesophagal and alveolar pressures over a breathing cycle. Work on silica solubility has emphasized the necessity of removing surface impurities from the quartz dust particles. Samples which reacted quite differently to cell preparations could be brought into line by purification. Permissible levels of dust in German coal mines are linked with the quartz content, which is often low. The attenuated total reflection system of i.r. spectrometry has been investigated as a method of analysis, the dust being collected on a membrane filter and placed in optical contact with a crystal of higher refractive index. The limit of detectability is about 0.005 mg quartz. Mixed dust pneumoconiosis has occurred in miners of iron ore, the dust containing about 60 per cent iron and up to 10 per cent quartz; an investigation has suggested that the disease is benign or non-progressive. Some work has been carried out with magnesium and calcium adipiodon, agents which are used to render the lung airways radio-opaque for diagnostic purposes. Dogs and rats were employed, the agent being inhaled by the former and injected into the trachea or peritoneum of the latter. The agents are not eytotoxic but increases in the weight of lung and lymph nodes followed intratracheal injection due to the production of mucus which caused temporary bronchial obstruction. Experiments on diffusiophoresis suggest that the effect on particle deposition of the opposing flows of carbon dioxide and oxygen is negligible because they cancel out. Studies of air filtration have shown that dust particles fail to adhere to filter fibres, especially large particles at high face velocities. Coating the fibres with oil makes an enormous improvement in efficiency. A design for an air cleaner which uses an aqueous solution of calcium chloride to secure adhesion of particles is presented. Fine dust can be filtered provided that the face velocity is high enough to ensure good filtration by impaction on the fibres. An important part of the work of the Institute is the testing of mining equipment. Some results are shown for pneumatic picks and hydraulic valves. Tests of sampling instruments have also been carried out underground, including the MPGII, which seems to be a copy of the British Hexhlet, and the British SMRE Simpeds 70 MK2. C. N. DAVIES
274
REPORT Bericht des Silikose-Forschungsinstituts der Bergbau Berufsgenossenschaft. 1973. pp. 125, 463, Bochum, Hunscheidstrasse 18, Germany. The 1972 report of the Silicosis Research Institute was reviewed in the d. Aerosol Sci. 5 (3), 321. The interest of the Medical Division in proteolytic enzymes continues; they contribute to chronic obstructive bronchitis through the release of debris of tissue and bacteria, a complicated spectrum of proteases and inhibitors being involved. Work has been carried out, using dogs, on the effect of the vagal reflex upon the ventilation-perfusion ratio; it is concluded that the vagal nerve has no influence and that gas regulation is probably centred on the alveolar regions. Studies of the mechanics of breathing furnish some interesting data on airway resistance in normal patients and those with obstruction and emphysema; there are diagrams of oesophagal and alveolar pressures over a breathing cycle. Work on silica solubility has emphasized the necessity of removing surface impurities from the quartz dust particles. Samples which reacted quite differently to cell preparations could be brought into line by purification. Permissible levels of dust in German coal mines are linked with the quartz content, which is often low. The attenuated total reflection system of i.r. spectrometry has been investigated as a method of analysis, the dust being collected on a membrane filter and placed in optical contact with a crystal of higher refractive index. The limit of detectability is about 0.005 mg quartz. Mixed dust pneumoconiosis has occurred in miners of iron ore, the dust containing about 60 per cent iron and up to 10 per cent quartz; an investigation has suggested that the disease is benign or non-progressive. Some work has been carried out with magnesium and calcium adipiodon, agents which are used to render the lung airways radio-opaque for diagnostic purposes. Dogs and rats were employed, the agent being inhaled by the former and injected into the trachea or peritoneum of the latter. The agents are not eytotoxic but increases in the weight of lung and lymph nodes followed intratracheal injection due to the production of mucus which caused temporary bronchial obstruction. Experiments on diffusiophoresis suggest that the effect on particle deposition of the opposing flows of carbon dioxide and oxygen is negligible because they cancel out. Studies of air filtration have shown that dust particles fail to adhere to filter fibres, especially large particles at high face velocities. Coating the fibres with oil makes an enormous improvement in efficiency. A design for an air cleaner which uses an aqueous solution of calcium chloride to secure adhesion of particles is presented. Fine dust can be filtered provided that the face velocity is high enough to ensure good filtration by impaction on the fibres. An important part of the work of the Institute is the testing of mining equipment. Some results are shown for pneumatic picks and hydraulic valves. Tests of sampling instruments have also been carried out underground, including the MPGII, which seems to be a copy of the British Hexhlet, and the British SMRE Simpeds 70 MK2. C. N. DAVIES
274