The remaining two U.S. participants in the competition were defeated in the quarterfinals during the final day at the Junior World Freestyle Wrestling Championships in Istanbul, Turkey, Sunday, August 31.    Falling in the quarterfinal round were Andy Simmons (Williamston, Mich./Michigan WC) at 66 kg/145.5 lbs. and Kurt Backes (Neshanic Station, N.J./Cyclone WC) at 84 kg/185 lbs.    Simmons was defeated in his quarterfinal match by Abbas Rangbar of Iran, 8-3. According to the official web page, Simmons placed sixth in his weight division.    Backes dropped his quarterfinal match to Georgiy Tibilov of Russia. The score of that match is currently not available. According to the official web page, Backes placed fifth in his division.    The Junior World Championships feature the world's best wrestlers who are 17-20 years old.    With the losses on Sunday, the U.S. team completed the Junior World Freestyle Championships without a medal.    Four American wrestlers finished in the top 10 of their divisions. Placing fourth at 50 kg/110 lbs. was Paul Donahoe (Davison, Mich.). Backes was fifth and Simmons was sixth. Taking seventh at 74 kg/163 lbs was Don Reynolds (New Lenox, Ill./Overtime WC). The other four U.S. athletes did not place in the top 10, and did not score team points for the United States.    According to U.S. coach Troy Steiner, the United States placed in sixth as a team. Russia won the team title, closely followed by runner-up Iran.    The U.S. athletes were coached by Troy Steiner of Madison, Wis. and Donny McPherson of Portland, Ore.    JUNIOR WORLD CHAMPIONSHIPS  At Istanbul, Turkey, August 31    U.S. Junior World Freestyle Team results    50 kg/110 lbs. - Paul Donahoe (Davison, Mich.), 4th - tech. fall over Frank Osei Mensah (Canada), 10-0; dec. Evgeni Nikanorov (Israel), 9-8; lost dec. to Bahrami Farzan (Iran); lost dec. to Maksim Petrov (Bulgaria), 6-4    55 kg/121 lbs. - Mike Silengo (Colorado Springs, Colo./Dave Schultz WC), dnp/22nd - lost dec. to Anil Kumar (India), 7-3; lost dec. to Malkhaz Kurdiani (Georgia), 8-6    60 kg/132 lbs. - Nate Gallick (Tucson, Ariz./Cyclone WC), dnp/11th - dec. Luis Ortiz (Puerto Rico), 8-2; tech. fall Bevilacqua Cianmarco (Italy), 10-0; lost dec. to Koba Kakaladze (Georgia), 4-0    66 kg/145.5 lbs. - Andy Simmons (Williamston, Mich./Michigan WC), 6th - tech. fall over Salvis Pudovs (Latvia), 15-5; tech. fall Scott MacGregor (New Zealand), 10-0; tech. fall Goran Atanosa (Macedonia), 10-0; lost dec. to Abbas Rangbar (Iran), 8-3    74 kg/163 lbs. - Don Reynolds (New Lenox, Ill./Overtime WC), 7th - dec. Sanjar Shodmanov (Uzbekistan), 8-0; dec. Tyler Marghetis (Canada), 6-1; lost dec. to Sergey Vitkovsky (Russia), 6-0    84 kg/185 lbs. - Kurt Backes (Neshanic Station, N.J./Cyclone WC), 5th - won by inj. dft. over Imants Lagodskis (Latvia); tech. fall Jonathan Rioux (Canada), 11-1; pin Navender Kumar (India); lost dec. to Georgy Tibilov (Russia), (score not available)    96 kg/211.5 lbs. - Nathan Moore (Indianapolis, Ind./Purdue), dnp/18th - lost dec. to Andre Podsevalnicov (Moldova) 7-6; lost dec. to Dragomir Stoychev (Bulgaria), 3-1; lost dec. to Yacheni Zabela (Belarus), 3-2    120 kg/264.5 lbs. - Cole Konrad (New London, Wis./Minnesota Storm), dnp/14th - dec. Petro Raychev (Ukraine), 5-2; lost dec. to Jamerlan Piliev (Russia), 5-0    Medal winners from all eight divisions    50 kg/110 lbs. - Gold - Bahrami Farzhan (Iran); Silver - Zhassulan Mukhtabekuly (Kazakhstan); Bronze - Maksim Petrov (Bulgaria)    55 kg/121 lbs. - Gold - Ersin Cetin (Turkey); Silver - Adam Batyrov (Russia); Bronze - Youri Holub (Ukraine)    60 kg/132 lbs. - Gold - Makhach Murtazaliev (Russia); Silver - Meiremzhan Baisebayev (Kazakhstan); Bronze - Gergoe Waller (Hungary)    66 kg/145.5 lbs. - Gold - Geandry Garzon (Cuba); Silver - Suren Markosyan (Armenia); Bronze - Niranjan Singh (India)    74 kg/163 lbs. - Gold - Sergey Vitkovskiy (Russia); Silver - Misan Amini (Iran); Bronze - Gabor Hatos (Hungary)    84 kg/185 lbs. - Gold - Georgi Tibilov (Russia); Silver - Steffen Hartan (Germany); Bronze - Yumagali Mamutov (Kazakhstan)    96 kg/211.5 lbs. - Gold - Magomed Ibragimov (Uzbekistan); Silver - Mohammad Khalegi Far (Iran); Bronze - Muhamet Bingoel (Turkey)    120 kg/264.5 lbs. - Gold - Mohammad Hadi Pouralijan (Iran); Silver - Daniel Chintoan Rares (Romania); Bronze - Tamerlan Piliev (Russia)