Virtual reality environment design of managing both presence and virtual reality sickness.

It is difficult to design the Virtual Reality (VR) Environment which controls VR sickness and promotes presence. This is because the relationship between the user's susceptibility to VR sickness and a sense of presence, determined by velocity and visual angle of the visual information, involves a trade-off between the two. Then we propose the optimal value search system which computes efficiently the velocity and visual angle which control VR sickness and do not impair presence by taking account of a subject's characteristic.

Signaling mechanisms involved in protease-activated receptor-1-mediated interleukin-6 production by human gingival fibroblasts.

Human gingival fibroblasts (HGFs) express protease-activated receptor-1 (PAR-1) at high levels. In cultured HGFs, we studied the signaling pathway of thrombin-induced interleukin-6 (IL-6) production. The PAR-1 agonist peptide SFLLRN mimicked the thrombin-induced IL-6 production in the presence of amastatin, an aminopeptidase inhibitor.

Thrombin-induced Ca2+ mobilization in human gingival fibroblasts is mediated by protease-activated receptor-1 (PAR-1).

By reverse transcription (RT)-PCR analyses, human gingival fibroblasts (HGFs) were demonstrated to express mRNAs for protease-activated receptor-1 (PAR-1) and PAR-3, although the expression of PAR-3 was much weaker than that of PAR-1. The mRNAs for PAR-2 and PAR-4 were not found by RT-PCR. Furthermore, PAR activation was studied by monitoring cytosolic Ca(2+) concentration ([Ca(2+)]i) in cultured HGFs loaded with fura-2.