The relationship between oral malodor, gingivitis, and periodontitis. A review.

Volatile sulfur compounds (VSC) are a family of gases which are primarily responsible for halitosis, a condition in which objectionable odors are present in mouth air. Although most patients perceive this condition as primarily a cosmetic problem, an increasing volume of evidence is demonstrating that extremely low concentrations of many of these compounds are highly toxic to tissues. VSC may, therefore, play a role in the pathogenesis of inflammatory conditions such as periodontitis.

Ablation and chemistry of meteoric materials in the atmosphere of Titan.

We compute the input of meteoric materials expected on Titan, and integrate this dust model with an ablation model and a comprehensive chemical model, investigating the effects on the atmosphere and surface. We find that a water deposition of approximately 10-100 times the expected interplanetary dust flux, or a recent large impact, is required to produce the observed CO2 abundance. Ionisation due to meteoric activity is not likely to be higher than that due to other sources.