San Francisco Mayor Willie Brown led a delegation of business and government officials to Osaka this week to strengthen business ties between the two cities and offer support for Osaka's bid for the 2008 Olympics.The sister-city relationship celebrates its 40th anniversary this year. Last spring, Osaka Mayor Takafumi Isomura visited San Francisco to mark the relationship and Brown was returning the favor. "The sister-city relationship has generated numerous cultural exchanges and commercial ventures. For example, we're assisting this region in their efforts to build an 'Exploratorium,' a children's science museum," said Brown, who was making his first trip to Osaka since becoming mayor."We are also offering assistance to Osaka for the 2008 Games, in anticipation of their assistance for San Francisco's bid to host the 2012 Games," he said. The 23-member delegation arrived in Tokyo on Oct. 19 and visited Osaka on Oct. 22 and Oct. 23 before leaving for South Korea.As part of his plan to strengthen the San Francisco economy, Brown has helped turn old military bases into industrial centers. One, the former navy base at Treasure Island, will include a marina, police academy, a firefighter training school, soccer fields, film facilities and restaurants.Conversely, Osaka faces severe financial problems. The population and the economy have been declining over the past 25 years and the city still has about 1.7 trillion yen in bonds outstanding, a result of the bubble economy years. Waterfront projects like the Asian Trade Center and the World Trade Center, as well as newly built sports facilities, are 22 billion yen in debt.Brown said that during his meetings with Osaka officials he was asked how San Francisco has financed huge infrastructure projects. "Specific questions were asked about our $2.4 billion airport expansion program and how we would repay the debts," he said. "We explained very carefully how the debts would be serviced. We also explained how we would market Treasure Island and how it would be different from Osaka's Universal Studios theme-park project."Although there are no regular exchanges between San Francisco and Osaka bureaucrats and city council members at present, Brown said, "That's something we'd love to do." One of the first cities to send assistance after the Kobe earthquake was San Francisco. Although Brown was not able to get to Kobe, he expressed his thanks to local people and organizations who sent relief to San Francisco after the large quake there in 1989. "The Kansai region helped us out tremendously and we have been just as enthusiastic about helping Kobe," he said.