In biology, the active site is the region of an enzyme where substrate molecules bind and undergo a chemical reaction. The active site consists of residues that form temporary bonds with the substrate (binding site) and residues that catalyse a reaction of that substrate (catalytic site).
Seattle is rolling out 11 rainbow crosswalks in Capitol Hill this week, adding a colorful bang to the annual Pride celebration. The crosswalks cost the city $66,000, said Seattle Department of Transportation spokesman Rick Sheridan, and are permanent.
Pouring concrete is a moderately-difficult DIY project. The cost of a concrete walkway is largely determined by the type of concrete poured. A plain concrete walkway costs $4 to $6 per square foot. Adding a single color or simple finish to the concrete raises the price to $6 to $10 per square foot.