Boeing is still building the long-range, fuel-efficient planes, and it said on Friday that it has no plans to slow production.___ McDonald's sales fall again amid weakness in Asia NEW YORK (AP) â¿¿ McDonald's says a key sales figure dropped again in January as the world's biggest hamburger chain faced ongoing weakness in Japan and sales in China were hurt by a food scare and the timing of a holiday. The Oak Brook, Ill.-based company said global sales at restaurants open at least 13 months dropped 1.9 percent for the month. The figure is a key metric because it strips out the volatility of newly opened and closed locations. After years of outperforming rivals, McDonald's has been struggling amid intensifying competition and challenging economic conditions around the world. Late last year, the company ousted the head of its U.S. business after the sales figure dropped for the first time in nearly a decade. CEO Don Thompson, who took the top spot this summer, has vowed to add business by emphasizing value while planning a series of new limited-time offers to attract customers. ___ Watson's medical expertise offered commercially WHITE PLAINS, N.Y. (AP) â¿¿ Dr. Watson is accepting new patients. The Watson supercomputer is graduating from its medical residency and is being offered commercially to doctors and health insurance companies, IBM said Friday. IBM Corp., the health insurer WellPoint Inc. and Memorial Sloan-Kettering Cancer Center announced two Watson-based applications â¿¿ one to help diagnose and treat lung cancer and one to help manage health insurance decisions and claims. Both applications take advantage of the speed, huge database and language skill the computer demonstrated in defeating the best human "Jeopardy!" players on television two years ago. ___ Coal sales investigated by feds; no violations yet BILLINGS, Mont. (AP) â¿¿ The U.S. Department of Interior is investigating whether mining companies are skirting royalty rules as they increase exports of coal to Asia, but no violations have yet been issued, federal officials disclosed Friday.