Foreign Minister Antonio Tajani said in Shanghai Friday he hoped China could play a positive role for peace in Ukraine and Iran.     "I have strongly insisted that Beijing play a significant role in helping to stop the war in Ukraine, because no one has more influence on Moscow than Beijing, as can also be said for Iran," said Tajani, who is also deputy premier, emphasizing that "we hope China can play a positive role in building peace." "In last night's political meeting with Wang Yi (Chinese