(petitioner formed corporation to perform engineering consulting work and steel fabrication; steel fabrication business ultimately transferred into LLC and businesses separated; corporation used advanced funds from LLC and bank loans to continue operations; LLC claimed bad debt deduction on Form 1065 for 2006 and 2007 for amounts not repaid by corporation; IRS disallowed deductions on basis that they weren't bona fide debt; court agreed with IRS - advances not bona fide debt because no use of promissory note, lack of definitive maturity date, lack of repayment schedule, no collateral pledged and no interest paid or accrued; Tax Court decision affirmed on appeal)