LONDON (AP) -- Five things to know about Monday, Day 10 of the London Olympics:
-American judo fighter expelled for doping.
-Gabby Douglas last on uneven bars; Russia's Mustafina wins gold.
-Americans Dawn Harper, Lolo Jones into 100-meter hurdle semis.
-US women clinch boxing medals.
-IOC defends NBC's tape-delayed Olympics coverage.
American judo fighter Nick Delpopolo apologized Monday after he was expelled from the Olympics for doping, blaming the disqualification on his unintentional consumption of something baked with marijuana.
Delpopolo is the first of the 10,500 London Games athletes to fail an in-competition doping test.
The International Olympic Committee said it disqualified him from the 73-kilogram class, where he placed seventh. He beat opponents from Hong Kong and Belgium, then lost to fighters from South Korea and Mongolia. The IOC added that he tested positive for metabolites of cannabis after competing on July 30, the day of his event.
The judoka from Westfield, N.J., said his positive test was "caused by my inadvertent consumption of food that I did not realize had been baked with marijuana" before he left for the Olympics.
"I apologize to U.S. Olympic Committee, to my teammates, and to my fans, and I am embarrassed by this mistake," he said in a statement released by the USOC. "I look forward to representing my country in the future, and will rededicate myself to being the best judo athlete that I can be."
Defending Olympic 50K race walk champion Alex Schwazer also tested positive for doping, and the Italian Olympic Committee said he had been removed from the team. Schwazer was scheduled to compete on Sunday.
In gymnastics, Gabby Douglas was nowhere near the podium this time. The all-around champion, who also helped the United States to team gold, finished last on uneven bars. Russia's Aliya Mustafina rallied to the victory.
"Toward the end of the Olympics, you get mentally and physically tired and you're just like drained," Douglas said. "I tried to fight through it as much as I could."
Mustafina, who injured her left knee in April 2011, gave Russia its first gold in women's gymnastics in London. This completed her medal set following a silver in team competition and bronze in all-around.
Arthur Zanetti finished first on still rings for Brazil's first gymnastics medal, and Yang Hak-seon of South Korea added the gold on vault to his world title.
Defending champion Dawn Harper and American teammate Lolo Jones cruised into the semifinals of the 100-meter hurdles, but medal contender Brigitte Foster-Hylton is out after hitting the fifth hurdle in her heat.
Jones and world champion Sally Pearson won their heats, while Harper eased up near the line and finished second in hers. Pearson had the quickest time in the six heats, covering the distance in 12.57 seconds - the fastest first-round time in Olympic history.
Foster-Hylton threw herself to the ground after crossing the line, slapped the track, let out a scream and started crying. She then brushed aside Jones' attempt to console her.
"The emotions were just outpouring from her," said Jones, who was in the same heat as Foster-Hylton. "Even if she would have punched me, I totally would have understood."
In other preliminary events Monday, world-record holder David Rudisha of Kenya and Nick Symmonds of the U.S. were among those who advanced to the semifinals in the 800. World champion Jenny Simpson of the U.S. needed a late push to reach the women's 1,500. Fellow American Morgan Uceny also advanced.
Flyweight Marlen Esparza and middleweight Claressa Shields clinched the U.S. team's first two boxing medals. Esparza patiently outboxed Venezuela's Karlha Magliocco, and the 17-year-old Shields closed furiously in an 18-14 win over Swedish veteran Anna Laurell.
The Americans were in awe of the decibel-busting atmosphere in the Olympic debut of women's boxing.
"I had to keep myself calm out there," said Shields, who somehow managed to hear instructions her personal coach, Jason Crutchfield, shouted from the stands. "I didn't want to be overanxious, but it was kind of like, 'Wow.'"
Ireland lightweight Katie Taylor and top-seeded flyweight Ren Cancan of China also won.
The IOC defended NBC's decision to show Usain Bolt's 100-meter victory on tape delay, saying the network decides how it wants to air the events.
Bolt's blinding dash Sunday in the Olympics' signature event came at 4:50 p.m EDT. NBC broadcast the race on television hours later in prime time, frustrating fans accustomed to watching action as it happens and sharing instant reaction through social media. NBC is the biggest financial backer of the IOC.
"It's certainly not for us to tell them how to reach their audience," IOC spokesman Mark Adams said, adding that NBC live-streamed the race for online viewers. "If you wanted live, you could get it live."
Jay Cohen can be reached at http://www.twitter.com/jcohenap