The next question is whether the Federal Aviation Administration will agree to let the planes fly even though the root cause of a battery fire in one plane and a smoking battery in another is still unknown. The airliners, Boeing’s newest and most technologically advanced, have not been allowed to fly since mid-January following a battery fire in one plane and a smoking battery in another.

The plan — a long-term solution, rather than a temporary fix — calls for revamping the aircraft’s two lithium ion batteries to ensure that any short-circuiting that could lead to a fire won’t spread from one battery cell to the others, officials said. That would be achieved by placing more robust ceramic insulation around each of the battery’s eight cells. The aim is to contain not only the short-circuiting, but any thermal runaway, a chemical reaction that leads to progressively hotter temperatures.

FDA approves new targeted breast cancer drug

WASHINGTON — The Food and Drug Administration has approved a first-of-a-kind breast cancer medication that targets tumor cells while sparing healthy ones.

The drug Kadcyla from Roche combines the established drug Herceptin with a powerful chemotherapy drug and a third chemical linking the medicines together. The chemical keeps the cocktail intact until it binds to a cancer cell, delivering a potent dose of anti-tumor poison.

Cancer researchers say the drug is an important step forward because it delivers more medication while reducing the unpleasant side effects of chemotherapy.

The approval will help Roche’s Genentech unit build on the blockbuster success of Herceptin, which has long dominated the breast cancer marketplace. The drug had sales of roughly $6 billion last year.

NKorea to allow mobile Internet for foreigners

PYONGYANG, North Korea — North Korea will soon allow foreigners to tweet, Skype and surf the Internet from their cellphones, iPads and other mobile devices in its second relaxation of controls on communications in recent weeks. However, North Korean citizens will not have access to the mobile Internet service to be offered by provider Koryolink within the next week.

The announcement comes just weeks after North Korea began allowing foreigners to bring their own cellphones into the country to use with Koryolink SIM cards, reversing a longstanding rule requiring most visitors to relinquish their phones at customs and leaving many without easy means of communication with the outside world.

EU says eurozone economy to shrink again in 2013

BRUSSELS — The European Union predicted Friday that the economy of the 17 member countries that use the euro will shrink again in 2013 even though it will see its fortunes improve in the second half of the year.

In its winter forecast, the EU Commission, the EU’s executive arm, said the eurozone is likely to shrink a further 0.3 percent this year, in contrast to November’s prediction of 0.1 percent growth.

The debt crisis and the associated belt-tightening are weighing on activity – official figures showed the eurozone contracted 0.6 percent in the final quarter of 2012 from the previous three-month period. The eurozone has been in recession – officially defined as two consecutive quarters of negative growth – since the second quarter of 2012, when concerns about the future of the euro were particularly acute.

Moody’s downgrades UK rating from AAA to AA1

LONDON — Credit ratings agency Moody’s Investors Service downgraded Britain’s government bond rating one notch from the top AAA to AA1 Friday, citing weaknesses in the economy’s medium-term outlook.

Moody’s said “subdued” growth prospects and a “high and rising debt burden” were weighing on the British economy. The agency said rising debt meant “a deterioration in the shock-absorption capacity of the government’s balance sheet, which is unlikely to reverse before 2016.”

It said, though, that “the U.K.’s creditworthiness remains extremely high,” and its outlook is stable.

Feds probe J&J on recalled hip implant marketing

TRENTON, N.J. — Federal prosecutors are investigating Johnson & Johnson’s practices in marketing a line of hip replacements recalled in 2010 because many had to be replaced within a few years — part of a string of more than 30 product recalls by the health care giant in the last 3 1/2 years.

The company’s annual report to the Securities and Exchange Commission states that the government has asked for additional documents from DePuy Synthes and two related subsidiaries. They have turned over the documents and are cooperating fully with investigators, the filing states.

DePuy Synthes is one of the world’s biggest makers of joint replacements, surgical trauma equipment and other orthopedic surgery products. J&J has had legal problems before over its artificial joints. Just days before the ASR systems were recalled, the Food and Drug Administration told DePuy to stop marketing its Corail Hip System for two unapproved uses.