A vacuum packaging machine for performing a vacuum sealing operation on product packages, comprises a vertical stack of vacuum chambers 4 which each manage to receive at least one unsealed product package 2 and are operable to perform an independent vacuum sealing operation on the least one product package 2. Using cameras, the disposition of the vehicle in its lane is determined by detecting the highway lines painted on the road. An exemplary method of treating tissue may include providing a surgical staple; urging the surgical staple into tissue, while the surgical staple has a first shape; and deforming the surgical staple into substantially a D-shape. The video elementary stream is then decoded by means of a variable-length decoder and provided to the data stream modifier. Finally, the deflecting arm and the curved portion combine to provide a surface used to finish a corner produced by a floor and a wall. Compositions containing these compounds facilitate delivery of biologically active polymers to cells in vitro and in vivo.