the groove or the cross sectional configuration of the groove may not vary along the length of the at least one groove 400 similarly combinations of such cross sectional configurations for the grooves could be utilized the cross sectional configuration of the groove or grooves 400 may be substantially symmetrical about the longitudinal axis 410 of groove 400 as illustrated in fig8 and 9 or the cross sectional configuration of the at least one groove may be substantially asymmetrical about the longitudinal axis 410 of the least one groove as illustrated in fig1 and 16 the cross sectional configurations of groove 400 can assume a variety of shapes some of which are illustrated in fig9 16 and include those cross sectional configurations which are substantially square shaped fig9 u shaped fig1 triangular or v shaped fig1 rectangular shaped fig1 and triangular or keyway shaped fig1 the wall surface 303 of each groove 400 may be substantially smooth such as illustrated in fig9 13 or wall surface 303 may be jagged or roughened as illustrated in fig1 and 16 as illustrated in fig1 wall surface 303 could also be provided with at least one protrusion 304 and at least one indentation 305 if desired and additional protrusions and indentations 304 305 could be provided as desired the depth d of groove or grooves 400 may fall within a range of approximately one half to approximately ten microns the width w of groove or grooves 400 may fall within a range of approximately two to approximately forty microns.