A method to control measurement messaging is performed at a mobile wireless device. The methods and devices are particularly useful in surgical suturing applications in which it is desirable to maintain tension on suture being delivered, yet to allow the tension to be released as desired without retracting the suture. The phase-shifted and polarized optical signal may be combined with the other polarized and modulated optical signal to obtain a polarization multiplexed optical signal. In another embodiment, a process may expose information on failure-tolerant regions of virtual address space such that a physical page of memory containing failures only in failure-tolerant regions may be used to store the data instead of using a pristine page. A reference distance between the first electrode and the reference electrode is known prior to the generation of the electrical field. Specifically, the invention relates to stains and methods of producing the stains, methods of staining cells for cytological or histological analysis to contrast the nuclear portion of the cell from the cytoplasmic portion, and systems and methods for illuminating a cytological sample.