Romney set to clinch GOP presidential nomination

After his close friend died from pancreatic cancer, 16-year-old Jack Andraka unleashed his hyper-drive intellect on preventing more cancer deaths. And as Jim Axelrod reports, the teen created a much faster and far cheaper detection method for pancreatic, ovarian and lung cancer.

The Federal Bureau of Prisons is reviewing the frequency and fairness of solitary confinement in all federal prisons. A rollback on "solitary" is already underway in some states. Randall Pinkston reports on the impact the rollback is having on Mississippi.

New questions are being raised concerning if anyone in the White House was aware of IRS targeting of conservative groups. Margaret Brennan reports on the new evidence that's heating up the controversy.

Excitement is growing as the drawing nears for the record-setting Powerball jackpot. Carter Evans reports from California, the latest player to join the multi-state lottery, where residents are buying up 10,000 tickets every minute.

The town of Granbury, Texas, was hit hardest by a string of 16 deadly tornadoes that struck the state. Anna Werner reports how the city's "Code Red" warning system helped kept residents alive.

Parts of the plains and Midwest are under the threat of severe weather, including possible tornadoes. Jim Axelrod speaks with CBS News weather consultant David Bernard about what to expect in the coming days.