dr. nancy snyderman. >> reporter: on a quiet little street in princeton, a craftsman is at work.nding countless hours in his attic workshop, he is surrounded by the simplest of tools. >> fastidious is the word. every little speck. >> reporter: with an old iron, a few bricks wrapped in paper, and a smooth piece of bone, 80-year-old bill strong restores and repairs children's books, bringing them back to life. so this is where the magic is made? >> well -- >> reporter: this is where the magic is saved. >> okay. >> reporter: bill has always had a passion for books, but saving broken ones, well, that started as a hobby and then grew into something more. what's the most special project you've ever done? >> oh, there's loads of them. it was a grandfather that brought me a book that his grandfather had given to him, inscribed. and he wanted me to fix it up so that he could catch a plane next week to go to colorado, inscribe it for his grandson. that's nice. >> reporter: for the last several years he's been donating his time and talents to the children's section of the princeton public l

nancy snyderman, as always, thanks. and by the way, we should point out, much more on this topic on the web. dr. ncy will host a live chat tomorrow afternoon on nightly.msnbc.com. but she won't be performing any primary care. >>> up next, what does april 12th mean to you? in the history business it means a lot of things. >>> and now a word about today. this day, the 12th of april, in history. in the history business this is a big one, from small events to large. on this date the union jack was first flown in britain. in this country it is national grilled cheese day. celebrity birthdays include the author tom clancy, david letterman. joe louis died on this date in 1981. also on this day in 1945 word arrived from warm springs, georgia that fdr had died. some people thought he'd be president for life. harry truman took over the job at a dicey time for the u.s. and the world. we were at war, after all. yuri gagarin woke up the world on this day in 1961 as the first man in space. just 20 years later the first space shuttle flew, the shuttle "columbia." and on this anniversary the remaining shuttles w

dr. nancy snyderman tells us what all this sleep deprivation does to the teen brain, what we're calling a work in progress. >> reporter: early morning in chicago, and it isn't easy for 15-year-old malik to wake up, or for his younger brother. >> it's a struggle every morning. their energy every morning, there's nothing coming at me. >> reporter: that begs the question, what affect does sleep or the lack of it have on the teen brain? this sleep scientist has been studying teens for decades. >> there is this mythology that the older you get, the less sleep you need. >> starting at 12, children's internal body clocks keep them up later even though they need nine hours and 15 minutes of sleep. and now research is finding that old fr adolescence might need more than that because their brains have a harder time recovering at night. >> in the older teenage years where really important circuitry is linking up, that this need for sleep could be even a little longer than for the younger teens. >> neuroscientist said during the late teen years, the frontal lobe of the brain starts to mature. the are

dr. nancy snyderman. >> that's it.etheless we often refer to our home moans out of whack. what does that mean? >> our bodies are cascaded with hormones. there's thepy tu tear glanld that goes to your thyroid gland that goes to your other glanlds, the pancreas, your kidneys, even the testicles and ovaries. they keep us in these biorhythms and when one is out of sync, you know, we sometimes feel this. but these are normal hormones that all human beings possess. >> what functions are controlled by our hormones? >> our most basic is our metabolism. >> it's stoked because i ran. >> our growth and development. mood swings. even if your thyroid is out of balance, you hear women talk about being fatigued or being hyperactive, a change in your skin. and women particularly when they're in the reproductive years will talk about estrogen and progesterone being an important part of not only reproduction but later when they go through perry menopausal systems. >> so it is real, it is science, and it's not something in our head. >> i

dr. nancy snyderman, it's always great to see you. thank you.. we appreciate it. >>> coming up, we've got new details on the shocking revelations of actress catherine zeta-jones. why she checked herself into a mental health facility. we've got more right after these messages. yeah but now i have nothing to eat sure you do. hey! you can have the pop tart! pillsbury toaster strudel. the one kids want to eat than listening to our favorite songs. there's nothing we love more than listening to our favorite songs. but our favorite thing is eating totino's pizza rolls. but our favorite thing is eating totino's pizza rolls. ♪ we're the kids in america ♪ oh, oh, oh love those jeans. $175. ch-ching! excuse me? ever consider showing your customers what other stores charge for jeans? um...no. when it comes to car insurance, progressive direct does. i saved hundreds when switching. that's a lot. the jeans are skinny. the savings... are fat. out there with a better way. now, that's progressive. [ male announcer ] every day, thousands of people are choosing ad

dr. nancy snyderman joins us as well. can i call you sid?and sweet. >> the article looks at the debate of cell phones and brain cancer. you look at old studies and new studies. from what you have found so far do you see definitively a connection betweenle cell phones and brain cancer? >> there are two major studies still pending, but as of now the evidence that moderate cell phone use has any link to brain cancer is very weak. >> you mention a recent study. you looked into people where their brain showed increased brain glucose activity immediately next to where the antenna would rest on their head. what is that? >> the brain uses glucose as fuel. >> right. >> so when cell phone users were exposed to cell phone activity some parts of the brain, you started metabolizing or using more fuel. >> what's the implication? >> we don't know. it turns out when we read a newspaper our brain blood glucose activity goes up and we don't think that causes cancerment whcancer. the activity shows some activity is registering in the brain on cell phone use bu