; and including such funds as may be necessary to support American overseas research centers: Provided , That funds appropriated herein are available for advance payments to independent contractors performing research services or participating in official Smithsonian presentations: Provided , That the Smithsonian Institution may expend Federal appropriations designated in this Act for lease or rent payments, as rent payable to the Smithsonian Institution, and such rent payments may be deposited into the general trust funds of the Institution to be available as trust funds for expenses associated with the purchase of a portion of the building at 600 Maryland Avenue, S.W., Washington, D.C. to the extent that Federally supported activities will be housed there: Provided further , That the use of such amounts in the general trust funds of the Institution for such purpose shall not be construed as Federal debt service for, a Federal guarantee of, a transfer of risk to, or an obligation of the Federal Government: Provided further , That no appropriated funds may be used directly to service debt which is incurred to finance the costs of acquiring a portion of the building at 600 Maryland Avenue, S.W., Washington, D.C., or of planning, designing, and constructing improvements to such building: Provided further , That the Smithsonian Institution may not sell its ownership interest, or any portion thereof, in such building without prior written notification to the House and Senate Committees on Appropriations 30 days in advance. Facilities capital For necessary expenses of repair, revitalization, and alteration of facilities owned or occupied by the Smithsonian Institution, by contract or otherwise, as authorized by section 2 of the Act of August 22, 1949 (63 Stat. 623), and for construction, including necessary personnel, $296,499,000, to remain available until expended, of which not to exceed $10,000 shall be for services as authorized by 5 U.S.C. 3109 . National gallery of art Salaries and expenses For the upkeep and