PubMed Health⌕ Search
Home/Archive/PubMed

PubMed · 9549910

Powered toothbrushes.

P Heasman
View original source ↗Export metadata ↓

Abstract

Powered toothbrushes were first developed over 50 years ago. More recent advances in design and technology mean that there are now a considerable number of different models available on the market. It is not surprising, therefore, that patients, when considering buying a powered toothbrush, often turn to their general dental practitioner for advice.

Explore related subjects

ElectricityHumansToothbrushingJournal Article

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

P Heasman. 1998-02-28. Powered toothbrushes.. https://doi.org/10.1038/sj.bdj.4809569

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2001

Monitoring of electrokinetic removal of heavy metals in tailing-soils using sequential extraction analysis.

This research focused on the monitoring of the electrokinetic removal of heavy metals from tailing-soils, and emphasizes the dependency of removal efficiencies upon their physico-chemical states, as demonstrated by the different extraction methods adopted, which included aqua regia and sequential extraction. The tailing-soils examined contained high concentrations of target metal contaminants (Cd=179mgkg(-1), Cu=207mgkg(-1), Pb=5175mgkg(-1), and Zn=7600mgkg(-1)). The removal efficiencies of the different metals were significantly influenced by their speciations, mobilities and affinities (adsorption capacities) in the soil matrix. The removal efficiencies of mobile and weakly bound fractions, such as the exchangeable fraction were more than 90% by electrokinetic treatment, but strongly bound fractions, such as the organically bound species and residual fraction were not significantly removed (less than 30% removal efficiencies). In accordance with the general sequence of mobilities of heavy metals in soils, the removal efficiencies of more mobile heavy metals (Cd, Cu, and Zn) were higher than that of less mobile heavy metal (Pb).

Electricity↗
PubMed2001

Sensitivity of leachate and fine contents on electrical resistivity variations of sandy soils.

Laboratory pilot tests were performed to investigate the relationship between electrical resistivity and contaminated soil properties. Three different sandy soils and leachate collected from one of the industrial waste landfill sites in Korea were mixed to simulate contaminated soil conditions. The values of electrical resistivity of the soils were measured using laboratory scaled resistivity cone penetrometer probe. In the experiments, electrical resistivity was observed in terms of water content, unit weight, saturation degree of the soils, and leachate concentration. The experimental results show that the electrical resistivity of the sandy soils depends largely on the water content and electrical properties of pore water rather than unit weight and types of soils. The amount of fines can have significant effect on electrical properties of soils. Direct correlation with contamination in such soils may not be valid here. The results suggest that the electrical resistivity measurement is well suited and applicable for monitoring and delineation of contaminants in the subsurface.

Electricity↗
PubMed2001

Extremely high electric field strengths in non-aqueous capillary electrophoresis.

The influence of high electric field strength on the separation of basic analytes in non-aqueous alcohol background electrolyte (BGE) solutions was investigated. Increasing the separation voltage in capillary electrophoresis (CE) may be advantageous if the conductivity of the BGE solution is low enough to allow fast separations without excessive Joule heating or band broadening. The voltage range tested was 20-60 kV with methanol and ethanol, and 25-60 kV with propanol and butanol as solvent for BGE. The resulting electric field strengths ranged from 660 V cm(-1) to 2000 V cm(-1). Experiments were made with a special laboratory constructed CE instrument. The separation efficiency vs. voltage curve was found to vary with the alcohol BGE solution. The increase in voltage decreased the separation efficiency in the case of methanol BGE solution, but with the other BGEs a clear efficiency maximum was obtained above 30 kV. The highest separation efficiencies were achieved with propanol BGE solution, where the efficiency maximum was reached at 45 kV. However, reasonable efficiency was achieved even at 60 kV. The extent of Joule heating was determined by calculating the temperature inside the capillary and the observed plate heights were interpreted in terms of the Van Deemter equation. The decrease in the separation efficiency with higher voltage was attributed mainly to Joule heating in the case of methanol and ethanol BGE solution and to the analyte adsorption on the capillary wall with propanol and butanol BGE solutions.

Electricity↗