Reporting in the journal Nature Communications,researchers write that they were able to track down the cells causing clogged arteries. Dr. Jill Helms, co-author on the study, discusses why stem cells are to blame and how the study could lead to more effective treatments.

SpaceX's Dragon capsule has travelled safely to the International Space Station and back. The next step, says Space.com writer Clara Moskowitz, is to outfit the capsule for crew, which SpaceX hopes to complete by 2015. Until then US astronauts will hitch rides on Russia's Soyuz, at about $60 million a pop.

The days are getting longer, and the kids are getting antsier.

Summer must be right around the corner.

So earlier this week, we led a chat on Twitter with Dr. Robert Block, a pediatrician who is president of the American Academy of Pediatrics, about some tips for a healthier summer.

In an action-packed half-hour, he tackled questions ranging from how to pick a sunscreen to how to get kids to eat better.

Here are some highlights from the chat, which was tagged #nprkids, on Twitter.

.

It could very well end up being the song of this summer. Carly Rae Jepsen's "Call Me Maybe," a sunny pop song about a nascent crush, is No. 2 on the pop charts and No. 1 on iTunes.

But, perhaps the bigger sign that it has just crept everywhere is when someone on the Internet mashes up a President Obama remix.

More than 10,000 of you took our recent survey about how your family meals stack up against the Obamas'. And it turns out, you're a pretty healthy bunch.

This sounds like something we said in first grade:

Transcript

RENEE MONTAGNE, HOST:

And today's last word in business is: Don't drive like my brother. That's the sign off heard each week at the end of NPR's most popular program. Were talking, of course, about CAR TALK. Brothers Tom and Ray Magliozzi have been dispensing humorous auto advice on the radio for more than 25 years. But today, the duo said they're putting the breaks on the program. In October they'll call it quits and no longer record new episodes.

An operation by U.S. Immigration and Customs Enforcement's (ICE) Homeland Security Investigations (HSI) has led to the arrest of 190 people accused of producing, distributing or possessing child pornography.

"Let this operation be a warning to anyone who would think they can use the Internet to exploit children: we are out there looking for you, we will find you, and you will be prosecuted," ICE director John Morton said in a statement.

I'll Have Another, which was set to run for racing glory in Saturday's Belmont Stakes, will not be racing for the Triple Crown.

"History is going to have to wait for another day," owner J. Paul Reddam said during a press conference at Belmont Park, today. Reddam said I'll Have Another, who had good odds of becoming the first winner of a Triple Crown since 1978, was suffering from tendinitis in his left, front tendon and that the colt's racing career was over.

Transcript

RENEE MONTAGNE, HOST:

One thing about the economic pain Spain, and other EU countries, are now experiencing - it's offering something of a break to President Obama in this campaign season, where he's trying to fend off Republican attacks on his handling of the sluggish American economy. In a White House press conference this morning, the president was able to point to Europe's financial woes as a drag on the economy here in the U.S.