Referring to FIG. 7A, shown is a schematic drawing illustrating a top view of a needle and barrel assembly 500 with the needle extended outside the barrel, according to a fourth embodiment of the invention; FIG. 7B illustrates a left side-view of the apparatus shown in FIG. 7A; FIG. 7C illustrates a right side-view of the apparatus shown in FIG. 7A; FIG. 7D illustrates a cross-sectional view throu