Sias R. Grobler

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A potentiometric sensor has been developed by coupling dental plaque with a flat-surface glass electrode. Selectivity of this electrode for hexoses and pentoses has been tested. The electrode responds linearly to beta-d(+)glucose, d(+)mannose, d(+)galactose and beta-d(-)fructose over a narrow concentration range between 10(-4) and 10(-3)M, but has(More)
The pH of cool drinks and fruit juices is very low and ranges from 2,4 (Pepsi Cola) to 3,7 (fresh orange juice). The osmotic concentration of most cool drinks and fruit juices is considerably higher than that of blood and, with the exception of Isotonic Game, ranges from 430 mOsm/kg (Coca Cola) to 1 297 mOsm/kg (Liquifruit Grape). Glucose, fructose and(More)
The range of fluoride levels in the drinking-water of cities and villages in South Africa was determined during the transition from a very dry (1983) to a wet (1984/85) period. The combination fluoride ion selective electrode was employed for the determination of the fluoride concentration. It was found that fluoride levels in drinking-water changed for 93%(More)
The purpose of this study was: (1) to measure the lead concentrations in various parts of the teeth (enamel, dentine and circumpulpal dentine) and in blood from individuals of a remote rural South African community; (2) to investigate any correlation between the lead concentrations in these various dental tissues and in blood; and (3) to estimate blood lead(More)
Lead pollution can produce a variety of effects on the human body. Shed deciduous teeth were collected from primary school children in urban, suburban and rural areas in South Africa. The lead content was determined through atomic-absorption spectrophotometry. The average circumpulpal dentine lead levels in the urban, suburban and rural samples are 74.5,(More)
Groups of 20 inbred rats were exposed to: (1) "clean air" (0.05 micrograms Pb/m3) for 70 days; (2) 77 micrograms Pb/m3 for 70 days; (3) 249 micrograms Pb/m3 for 28 days; and (4) 1546 micrograms Pb/m3 for 50 days. Half the rats in each group were then killed and the other half kept in "clean air" until the blood lead of groups 1-3 had returned to normal.(More)
Pregnant rats were dosed with 0, 3 or 10 parts/10(6) lead (as acetate) in their drinking water, during pregnancy and during lactation until 21 days post partum. The litters were killed at the age of 21 days and the incisors, first, second and third molars analysed for lead by atomic absorption spectrophotometry. The findings confirmed that even at low(More)
It could be expected that the degree of enamel erosion by different fruits containing different kinds of organic acids, or different ratios of acids, and other different chemical components, will vary. The aim of this study was to investigate the degree of enamel erosion by different kinds of fruits (by determining the depths of enamel removed at different(More)
A potentiometric sensor has been developed, based on selective fermentation of carbohydrates by Streptococcus mutans. This combination of bacterial action and a glass electrode responds to beta-d(+)glucose, d(+)mannose and beta-d(-)fructose over a narrow concentration range, with a response time of 4 min, and has negligible response to other hexoses and(More)