PubMed · 972933
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H J Terry. 1976. A fibre-optic microdensitometer.. https://doi.org/10.1088/0031-9155%2F21%2F4%2F120
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A recently developed technique of diffusive gradients in thin films (D6T)-computer-imaging densitometry (CID) was improved to study in situ two-dimensional distributions of sulfide in sediment interstitial waters adjacent to the DGT device. The in situ profiler accumulates sulfide from the sediment interstitial water through a diffusive gel onto a AgI binding gel to form black Ag2S. The amount of sulfide bound in the binding gel is then determined from the gray scale density of the dried binding gel. New gel-making procedures were employed to produce stable, evenly dispersed AgI binding gels and to minimize the darkening of the AgI gel upon exposure to light The improved DGT-CID technique was used to profile the distribution of sulfide in sediment interstitial waters at Delta Marsh, a highly productive Prairie wetland on the south shore of Lake Manitoba, at a vertical and lateral resolution of < or = 0.4 mm. The in situ high-resolution microprofiles revealed unprecedented two-dimensional heterogeneity in sulfide concentrations in the sediment interstitial waters adjacent to the DGT device. The mosaic distribution of oxic and sulfidic microenvironments suggested not only the complexity and heterogeneity of the biogeochemistry of sulfur species and sulfide-binding metals (e.g., Cd, Cu, Pb, Hg, Zn) in sediments but also the capability of aquatic organisms for coping with the sulfidic environment
UNLABELLED: Putrefaction of saliva is commonly used as an in-vitro assay in oral malodour investigations. AIM: To exam the hypothesis that deglycosylation of salivary glycoproteins promotes oral malodour production. DESIGN: Porphyromonas gingivalis-mediated putrefaction of salivary glycoproteins was tested following preincubation of saliva in the presence of beta-galactosidase with or without glycosidic inhibitor (galactosamine), and in the presence of glucose with or without a non-glycosylated protein (bovine serum albumin). METHODS: Malodour was determined by two odour judges, and volatile sulphides by using a sulphide monitor. Salivary glycoprotein degradation was measured densitometrically following electrophoresis on SDS-PAGE. RESULTS: The addition of beta-galactosidase promoted salivary glycoprotein degradation and concomitant malodour production, whereas addition of a glycosidic inhibitor (D-galactosamine) inhibited this process. Glucose inhibited salivary glycoproteins putrefaction, but this inhibitory effect was mitigated when a non-glycosylated protein (BSA) was added. CONCLUSIONS: Deglycosylation of salivary glycoproteins may be an initial step in oral malodour production. This process exposes the protein core of the glycoprotein, which is then further degraded by Gram-negative microorganisms under anaerobic conditions.
Opening of the first door of pulse photometry gave us pulse oximeter. The next door opens to multiwavelength pulse photometry. It will give us a high performance pulse oximeter, providing a wide variety of clinical information simultaneously. This next generation of pulse photometry should further improve bedside monitoring and patient care.