Responsibility. Elaine. Holly williams in egypt, thank you. President obama arrived in vietnam sunday. He is only the third sitting u. S. President to visit the communist nation. Later this week, hell be in japan. Margaret brennan is traveling with the president and joins me from hanoi. Margaret, what is the president hoping to achieve on this trip . Well, elaine, the goal here in vietnam is to turn this former foe into a friend. And in doing so send a very strong message to china that the u. S. Will not let them militarily dominate all of asia. China is currently locked in a number of territorial disputes in south and east china seas. So president obama is kidding expanding weapons sales to vietnam. Thats a ctr kidding that this country is still run by an authoritarian communist government. Margaret, later this week the president will be the first sitting president to visit it hiroshima. Why has he decided to go . Well this extremely symbolic visit is mainly to underscore his legacy of securing Nuclear Weapons through arms control deals like the one he brokered with iran. So, in hiroshima, president obama will be underscoring the fact that the very first atomic bombs ever dropped were by the u. S. On japan in 1945. And they killed hundreds of thousands. So, he is not going to apologize for those attacks, but he will say that it gives the u. S. A unique responsibility to make sure that no Nuclear Weapon is ever used again. All right, Margaret Brennan in hanoi, vietnam. Thank you so much. E cbs overnight news will be right back. Helps students develop strong Critical Thinking skills [boy] kinda like exercising my brain . Yeah see this old question . It doesnt tell me whether you understand the math, because you can just guess and get it right. [boy] eenie meanie miny mo [woman] exactly. Now try this new kind of question. [boy] hm, 3 2 is the same as 3 one halves; thats here at one and one half [woman] right now i can see that you really understand fractions. And the number line. [woman. Laughs] ah haha a new cbs news poll today shows how donald trump and Hillary Clinton match up in two key battleground states. Julianna goldman in the Washington Bureau with the latest on the president ial campaigns. You know running for president is hard. I got to tell you. Reporter as Hillary Clinton and donald tru p election, a cbs news poll shows tight races in two states. Clinton and trump tied in florida with clinton one point ahead. In ohio, the democratic frontrunner leads the presumptive nominee by five points. 44 to 39 . I am going to be the nominee. I do think there will then be the obvious need for us to unify the party. I think secretary clinton is jumping the gun a little bit here. Bernie sanders in ohio is beating trump by nine points. Helped by young voters and independents. Both parties are unifying behind their nominee helped by voters Backing Trump and clinton because theyre against other side. I will be running against donald trump in the fall. I do not want americans and good thinking republicans as well as democrats and independents to start to believe that this is a normal candidacy. On fox the billionaire businessman warned that sanders criticism of clinton has been tame compared. She shouldnt be allowed to run for president. She has bad judgment. Hillary is weak, a weak person. Two National Polls out today showed trump and clinton are the least popular likely nominees in modern history. More than half registered voters have negative opinions. And 47 would consider a third party candidate. Thank you. Trouble on mt. Everest. Altitude sickness apparently claimed the lives two of climbers in recent days. And dozens more are struggling. Demarco morgan tracking it all from here in new york. Demarco. What a story. An official in nepal says 30 climbers have gotten frost bite or become sick on mt. Everest the two climbers did not make it down from the tallest mountain. 30yearold dutch climber, eric arnold died after complaining of feeling weak. He was able to get to lower altitude. Maria strydom showed signs of altitude sickness before she died. Some climbers were as high as 21,000 people. No word on the where abuts of two climbers last seen near the summit. Jim davidson knows about the challenges. With 30 years of experiences climbing the worlds tallest peaks. Up on the summit of everest it is 66 lower in oxygen availability. So as a result you can barely, stew stand up and walk, 20 feet across the ground can make your heart pound in your chest, make your head throb and make you dizzy, literally standing up and walking, 20, 30 feet. Last years climbing season was canceled after the earthquake wreaked havoc on the area. Climbing attempts were halted in 2014 soon after an avalanche killed more than a dozen sherpa guide. More than 250 people have died in the efforts off to climb mt. Everest. Elaine since the first historic trek recorded back in 1953, it has been an issue. Absolutely punishing conditions on the mountain. Demarco morgan. Thank you. Two horses died saturday at the preakness stakes in baltimore. The tragedies are reigniting concerns about the sport. Reporter there were celebrations at the Winners Circle for preakness winner exaggerator. But his moment of triumph overshadowed by the loss of two horses. 9yearold homeboy chris won the first preakness contest in maryland, then collapsed and died moments after having his photo in the Winners Circle. Chris campitelli tweeted devastating loss. Homeboykris died from apparent heart attack on walk back to arm after preakness day win. Later, the 4yearold horse had to be euthanized breaking her left leg coming out of the final turn. The on call veterinarian. An open wound. And that, that just does not have the possibility of surgical fixation. They grew up. Veterinarian, dr. Gregory barbosa says the horses are specifically bred to race. When you have a good racehorse, you know you do, they want to run. Bred to do and feel good when they do it. Reporter the jockey club released statistics showing 14 decrease in the frequency of fatal injury. 484 horses died at race tracks in 2015. 583 died in 2014. Both horses will undergo analysis to determine what went wrong. People for ethical treatment of animals, peta is asking veterinary records be released and medications used up two two weeks before race day. Elaine. Jamie yuccas, thank you. Coming of on the cbs overnight news a paralyzed man find new hope in an experimental stem cell treatment. A place like shhh and definitely lipton ice tea. Lots of it. A lipton meal is what you bring to it. And the refreshing taste of lipton iced tea. 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Call now for your free information kit. Introducing new ky touch gel creme. For massage and intimacy. Every touch, gently intensified. A little touch is all it takes. Ky touch. An experimental procedure aimed at repairing spinal cord injuries is showing promise. It uses stem cells in the damaged areas in hopes of restoring function and movement. Dr. Jon lapook has one patients story. There its nothing we could have done to change that night. Reporter april 9, 2013, james mason was an accident waiting to happen. He had been drinking and his stepfather, bob gambutti tried to stop him from driving. He grabbed on to me. I grabbed on to him. He pulled my leg out. He fell back. His neck broke. I remember hitting the ground. With the stretcher. Most devastating part, the first day they lifted him out of the bed and nothing moved. Just his head. That really hit hard. At that point, i really wanted to go jump off a bridge. Mason was left a quadriplegic with just the slightest ability to move his arms. Doctors shed would never talk again. Gambutti, a retired cop became his full time care giver and found a trial at mount sinai hospital. Take good care of you. Reporter we spoke with mason before he underwent delicate neck surgery to try to repair the damaged portion of the spinal cord by injecting stem cells. What is going on in your head, what are you thinking, hoping for . Just super excited ready to get it done. And go back to rehab. And start proving the doctors wrong even more. Slow. Reporter the surgery performed by dr. Arthur jenkins took four hours. Researchers followed james and five patients all with severe spinal cord injuries. We met up three months after the surgery. Notice any change . My wrist has the got in a lot stronger. Able to grasp around a lot of other things. And after another three months. Almost doubled with how much i have gotten better. The sensation back into my feet. I can feel pressure on to them. Throughout my legs. And they have noticed that i have a little bit of movement into my hips now. Today the company sponsoring the trial reported four of the six patients experienced improvement in both muscle strength and function. Dr. Jenkino affiliated with the company continued to monitor mason. My two cents is, it worked. That this actually changed neurologic recovery and function. That his actual functional improvement is from the stem cells injected. Mason does not blame his step father for the accident. In fact, he is grateful. I had gotten in my car i could have killed some one else. Someones mother. Father. Some ones child. I wouldnt have, if i would have survived through that. I wouldnt be able to live with myself with that. Its tough people. Say im sorry. Dont beep sorry. I still have him here. Reporter mason believes the stem cells accelerated his recovery. Hard to know what would have happened without them. More research will be needed to try to establish whether they repair damage to the spinal cord. Dr. Jon lapook, cbs news. Still ahead on cbs overnight news, the unusual sight that brought travel tubing a crawl in los angeles. Space shuttle fuel tank the size of half a football field across 16 miles of los angeles. Onlookers took selfies and watched from rooftops as the tank rolled by. You are going to be a great astronaut. You smile a lot. Reporter it took months to choreograph this move. Police closed streets. Public works altered traffic lights and utility wires to make way for the 66,000pound tank. As the it skirted by trees. Traveling at just five miles an hour. Astronaut charlie precourt. Cant wait to see it stacked in vertical in the museum. It is going to blow people away. Reporter the fuel tank shipped from new orleans to california through the panama canal. It will eventually be displaced inside the California Science Center in full launch position. Attached to two rocket boosters and Space Shuttle endeavor which hitched a ride to los angeles on top of a 747 in 2012. The tank known as et94 was built to propel endeavor into space. Nasa phased out the Shuttle Program before it could launch. Astronaut kay higher, flew on endeavor and hopes seeing this will inspire young minds. Think about taking us beyond where we have been in space exploration. On to mars. Et74 on display in 2019. Elaine. Terry okita in los angeles. Thank you. Up next, a mother and daughter reunited after 50 years of separation. P . P . O . Gv finally tonight, a mother and her daughter separated decades ago. Have been reunited and Barry Peterson has their story. I am nervous. I am excited. And i waited 50 years for this moment. Reporter for cindy burns, the wait is almost over. It started when she was a 10monthold baby left with a korean adoption agency, amid that countrys poverty, this was a chance at a better life in america. Believed her korean mother, soonja. Did you believe you would see your daughter again . No. Dont believe it. Dont know how i will find her. Cindy grew up in a connecticut family. She had all but given up finding her birth mother. I had gone to korea last year. Kind of looking for her. And i made peace with the fact that i would probably never find her. Reporter when a dna sample led her to soonja. It says 99. 99 she is your biological mother. I so much wanted tight be true. Reporter there was more. Her mom had been living on the west coast, they had been in the same country for decades. Cindy flew to tacoma this weekend to meet her mom. Cindy. You are so beautiful. I always say where can i find her . I dont know where she is. We are back together now. Uhhuh. I know. Oh. When we sat with them, they couldnt stop holding each other. As if they were afraid they might lose each other again. What does it say about your mother that she was willing to be open about this secret that all of her life she hadnt shared with her family. Its confirmation that she did love me. Reporter at soons home there was a family reunion. Cindy with her newly found sisters and brother. It is what all of us who are adopted want is for our existence to be validated. Here we go to know our parents loved us. Reporter Barry Peterson, cbs news, tacoma, washington. Thats the cbs overnight news for this monday. For some of you the news continues. For others check back with us a little later for the morning news and cbs this morning. From the Broadcast Center in new york city. Announcer this is the cbs overnight news. Welcome to the cbs overnight news. About 180 miles off the egyptian coast the search continues for the black box data recorders from egyptair flight ms804. It went down thursday killing all 66 on board. Holly williams is in alexandria, egypt, with a newly release audio recording from the doomed jet. The recording captures a standard check in between the pilot and air Traffic Control over zurich, switzerland. Reporter 2 1 2 hours later the plane plunged into the water. Egypts president , abdel alsisi said his country is sending a submarine to recover the flight recorders or socalled black boxes in the same area where they found debris from the crash including human remains. Retrieving the black boxes in water up to 10,000 feet deep, could prove difficult. A u. S. Intelligence source told us that the flight recorders have been approximately located via the electronic pings they emit. But so far there has been no official confirmation. Data published by av herald, an Aviation Industry website appears to show there was smoke on board just before the plane crashed. Though experts say the smoke alarms could also have been triggered by a sudden loss in pressure. Allistair rosenshine is a former pilot with british airways. We can rule out say, pilot error, human error as we call it, because there is no human error that would have triggered smoke alarms. Reporter officially though, no cause has been ruled out. Including terrorism. Even though according to u. S. Investigators, there have been no credible claims of responsibility. Elaine. What are the possible causes of the deadly crash. John dickerson spoke with cbs news aviation and safety expert, captain sully sullenberger. Investigators will be talking to as many people as they can. Trying to interview any one who had anything to do with the flight. Any one who touched the airplane. I should till you that as aviation safety has become better, and accidents ha become more rare. Their causes have become more unique. Because aviation has done a good job of reducing eliminating what used to be many common causes of accidents. What we are left with is more black swan events. They will be looking in many different areas. As aviation safety has gotten better, there has to be more focus on aviation security. Whether or not this happens to be intentional act or not. For 30 years one of my biggest concerns is what would be called all the activities behind the scenes in the back of the house. So to speak. People who service and clean and cater the airplane. Some times the services are outsourced to Third Party Vendors they have high turnover. Whether this is a terrorism event or not. Global experience tells us we need to look at everybody touching the airplane and in this case. Flight ms804 had a busy trip to cairo. Previous spot was in paris. It has the french taking a new look at their security procedures. Mark phillips reports. Reporter there has been no evidence the egyptair crash had anything to do with security at anything to do with security at Charles De Gaulle airport. And whether there was a lapse that may have allowed an explosive device to be placed on board if there was. This isnt the first time they were worried. An official of the union that represents 5,000 security workers here. All of whom were subjected to renewed rigorous Police Checks following the paris terror attacks last year. And some of whom were found to be a security risk. Translator after the air is attacks they withdrew 85 badges. People who can no longer work in security. The airport sits in paris northern suburbs which have immigrants from muslim countries. Newt Security Checks look for evidence of radicalization, where the employees have traveled, what they read, who they associate with. Known as the insider problem and acknowledged here and elsewhere. Mike vivian, former head of operations for britain Civil Aviation authority. Clearly some countries, are possibly more vulnerable than others to this. It can be surreptitious, below the radar so to speak. A serious issue. It is being looked at. Reporter the fact that egyptair plane had been to tunisia, with Security Problems