Provided are techniques for populating a new text index. Probes comprising a crosslinking agent are combined with a sample which may comprise a target sequence which is complementary to the probe. The roller has at least one wear indicator operatively arranged for indicating wear of the covering. The resulting MCP structure is cost-effective as compared to conventional manufacturing processes and the resulting MCP structure exhibits a funneling effect. A preload is applied to all the three feed mechanisms, for X-axis, for Y-axis, and for Z-axis, using a rack-pinion, and using two motors for each axis to prevent backlash in the rack-pinion.