In this paper we show h o w to traverse a subdivision and to report all cells, edges and vertices, without making use of mark bits in the structure or a stack. We do this by performing a depth-rst search on the subdivision, using local criteria for deciding what is the next cell to visit. Our method is extremely simple and provably correct. The algorithm has applications in the eld of Geographic Information Systems GIS, where traversing subdivisions is a common operation, but modifying the database is unwanted or impossible. We show h o w to adapt our algorithm to answer related queries, such as windowing queries and reporting connected subsets of cells that have a common attribute. Finally, w e show h o w to extend our algorithm such that it can handle convex 3-dimensional subdivisions.

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The objectives of this study were to determine inhibitory effect on tyrosinase activity and antioxidant activity of the methanolic extract from grape seeds and to investigate relationships between tyrosinase inhibitory activity and antioxidant activity of the extract. The 80% methanol extracts of grape seeds were fractionated subsequently with hexane, chloroform, ethyl acetate and water. The methanolic extract and fractions from grape seeds inhibited tyrosinase activity in a concentration dependent manner. The methanolic extracts showed the highest inhibitory effects on tyrosinase activity. The inhibitory effects of the ethyl acetate fraction from the methanolic extract on tyrosinase activity was higher than other fractions. The ethyl acetate fraction from methanolic extracts showed higher antioxidant activity and contained higher polyphenolic and flavonoid contents compared to other fractions. The correlation coefficients among the polyphenoilc content of methanolic extracts, ABTS radical cation scavenging activity and inhibitory effect of tyrosinase were relatively high. These results suggest that grape seeds may have potential as a depigmentation agent for cosmetics and functional food products.

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