BUZZ-Oxford Instruments: worst 1-day pct move on profit warning
** Oxford Instruments (LSE: OXIG.L - news) slides 28 pct, poised for its biggest ever one-day drop, after says H2 revenue would come in below market expectations
** Co blames weak trading in Russia and Japan
** Share (LSE: SHRE.L - news) price drop wipes some $266 mln of co's market value
** Most actively traded midcap stock, with more than its 90-day daily avg volume having already gone through (RM (LSE: RM.L - news) : tricia.wright1.thomsonreuters.com@reuters.net)