ABSTRACT
Naturally occurring fogs in industrialized cities are contaminated by acidic air pollutants. In Brussels, Belgium, the pH of polluted fogwater may be as low as 3 with osmolarity as low as 30 mOsm. In order to explore short-term respiratory effects of a realistic acid-polluted fog, we collected samples of acid fog in Brussels, Belgium, which is a densely populated and industrialized city, we defined characteristics of this fog and exposed asthmatic volunteers at rest through a face mask to fogs with physical and chemical characteristics similar to those of natural fogs assessed in this urban area. Fogwater was sampled using a screen collector where droplets are collected by inertial impaction and chemical content of fogwater was assessed by measurement of conductivity, pH, visible colorimetry, high pressure liquid chromatography, and atomic absorption spectrophotometry over a period of one year. The fogwater composition was dominated by NH4+ and SO4- ions. First we evaluated the possible effect of fog acidity alone. For this purpose 14 subjects with asthma were exposed at rest for 1 hr [mass median aerodynamic diameter to a large-particle (MMAD), 9 microns] aerosol with H2SO4 concentration of 500 micrograms/m3 (pH 2.5) and osmolarity of 300 mOsm. We did not observe significant change in pulmonary function or bronchial responsiveness to metacholine. In the second part of the work, 10 asthmatic subjects were exposed to acid fog (MMAD, 7 microns) containing sulfate and ammonium ions (major ions recovered in naturally occurring fogs) with pH 3.5 and osmolarity 30 mOsm. Again, pulmonary function and bronchial reactivity were not modified after inhalation of this fog. It was concluded that short-term exposure to acid fog reproducing acidity and hypoosmolarity of natural polluted fogs does not induce bronchoconstriction and does not change bronchial responsiveness in asthmatics.
Subject(s)
Acid Rain/adverse effects , Asthma/physiopathology , Bronchial Hyperreactivity/chemically induced , Environmental Exposure , Acid Rain/analysis , Aerosols/administration & dosage , Belgium , Bronchoconstriction/drug effects , Chromatography, High Pressure Liquid , Colorimetry , Electric Conductivity , Female , Humans , Hydrogen-Ion Concentration , Male , Osmolar Concentration , Particle Size , Quaternary Ammonium Compounds/adverse effects , Respiratory Function Tests , Spectrophotometry, Atomic , Sulfates/adverse effectsABSTRACT
A patient with melorheostosis of the right lower limb is described with the clinical findings and radiographic appearances which include angiographs and microradiographs. Tissue was taken from the knee joint at the time of arthrodesis and examined by histological, histochemical and biomechanical techniques. It is concluded that the bone in melorheostosis is not different from normal bone.
Subject(s)
Bone and Bones/pathology , Knee Joint/surgery , Melorheostosis/diagnosis , Adolescent , Adult , Arthrodesis , Biomechanical Phenomena , Child , Female , Foot/diagnostic imaging , Humans , Knee Joint/diagnostic imaging , Knee Joint/pathology , Leg/diagnostic imaging , Melorheostosis/diagnostic imaging , Melorheostosis/pathology , RadiographyABSTRACT
A patient with melorheostosis of the right lower limb is described with the clinical findings and radiographic appearances which include angiographs and microradiographs. Tissue was taken from the knee joint at the time of arthrodesis and examined by histological, histochemical and biomechanical techniques. It is concluded that the bone in melorheostosis is not different from normal bone.
ABSTRACT
The distribution and concentration of dissolved aluminum in a vertical hydrographic profile in the Mediterranean Sea near Corsica are controlled by biological activity. The concentrations of dissolved silica and aluminum covary in the profile and exhibit minima coincident with the seasonal thermocline, a nitrate minimum, and an oxygen maximum. These observations support the hypothesis that the silicon and aluminum cycles in the oceans are linked through the activity of diatoms.
Subject(s)
Bone Plates , Humerus , Aged , Chemical Phenomena , Chemistry, Physical , Clinical Trials as Topic , Corrosion , Fracture Fixation/instrumentation , Humans , Humeral Fractures/surgery , Humerus/diagnostic imaging , Humerus/surgery , Male , Metals , Microscopy, Electron, Scanning , Radiography , Surface Properties , Time Factors , X-Ray DiffractionSubject(s)
Bone and Bones/metabolism , Electron Probe Microanalysis , Absorption , Adult , Apatites/metabolism , Bone and Bones/analysis , Calcium/analysis , Femur/analysis , Femur/metabolism , Humans , Magnesium/analysis , Magnesium/metabolism , Male , Methods , Microradiography , Middle Aged , Phosphorus/analysis , Phosphorus/metabolism , Sodium/analysisABSTRACT
Magnetite crystals larger than 2 micrometers are absent from rocks and fines. Smaller opaque spheres in the fines can tentatively be identified as magnetite. Their concentration is not higher than 1 x 10(-6) particle per particle smaller than 1 millimeter. In the fines from the sampling site, the contribution of material similar to type 1 carbonaceous meteorites is insignificant, either because it never existed, or because it was evaporated or comminuted by impact or was diluted by indigenous material. Other magnetite habits typical of carbonaceous meteorites or possibly of cosmic dust or comets were also sought without success-such as rods, platelets, framboids, spherulites, and idiomorphic crystals.