Lasers can cause damage in biological tissues, both to the eye and to the skin, due to several mechanisms. Thermal damage, or burn, occurs when tissues are heated to the point where denaturation of proteins occurs. Another mechanism is photochemical damage, where light triggers chemical reactions in tissue.
March 9: Teams are allowed to begin negotiating with other teamsâ players who are set to become unrestricted free agents at the end of the league year. This is the first time the NFL is providing a window to negotiate with other teamsâ free agents prior to the start of free agency.
1 Practice squad players are paid per week and can be released at any point during the season.  Practice squad players are free to sign with other NFL teams, assuming they are signed to the 53-man active roster. A practice squad player cannot be signed to another practice squad unless he is first released.