PROMISSORY NOTE

Exhibit 10.39

Creditor Use Only

PROMISSORY NOTE

(Commercial – Single Advance)

DATE AND PARTIES. The date of this Promissory Note (this “ Note ”) is April 13, 2009. The parties and their addresses are:

1. DEFINITIONS. As used in this Note, the following terms have the meanings set forth hereinbelow:

A. Lender/Borrower. “Lender ” and “ Borrower ” means those parties so designated hereinabove.

B. Note. “ Note ” means this Promissory Note (Commercial-Single Advance) and any extensions, renewals, modifications and substitutions of this Note.

C. Loan Documents. “ Loan Documents ” means this Note and all other documents evidencing, securing or pertaining in any way to this Note and the Loan.

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D. Loan. “ Loan ” means the lending transaction evidenced in part by this Note, including obligations and duties arising from the terms of the Loan Documents.

E. Property. “ Property ” means all property, real, personal or mixed, that secures the payment and performance of this Note and the other Loan Documents.

F. Index Rate: “ Index Rate ” means the highest U.S. “prime rate” determined by reference to the “Money Rates” section of The Wall Street Journal as long as the Index Rate is reported therein. If publication of the Index Rate in The Wall Street Journal is discontinued, Lender shall determine the Index Rate from other sources. If the Index Rate or information establishing the Index Rate no longer is available, Lender shall select a comparable index which shall become the Index Rate. Lender’s determination of the Index Rate in the absence of manifest error shall be conclusive and binding on Borrower.

G. Note Rate. “ Note Rate ” means a per annum rate of the greater of (x) six and one half percent (6.5%) or (y) the Index Rate on the date in question plus one percent (1%), but not to exceed the Maximum Lawful Rate. Notwithstanding the foregoing, if the Note Rate for any period is limited to the Maximum Lawful Rate, the Note Rate shall remain at the Maximum Lawful Rate until an amount of interest has accrued on this Note equal to the amount of interest which could not accrue on this Note because of the limitation of the Note Rate to the Maximum Lawful Rate.

H. Default Rate. “ Default Rate ” means a rate per annum of the lesser of (x) the Note Rate plus five percent (5%) or (y) the Maximum Lawful Rate.

I. Maximum Lawful Rate. “ Maximum Lawful Rate ” means the maximum lawful rate of interest which may be contracted for, charged, taken, received or reserved by Lender in accordance with the applicable laws of the State of Texas (or applicable United States federal law to the extent that such law permits Lender to contract for, charge, take, receive or reserve a greater amount of interest than under Texas law), taking into account all Charges made in connection with the Loan.

J. Charges. “ Charges ” means all fees, charges and/or any other things of value, if any, contracted for, charged, taken, received or reserved by Lender in connection with the Loan, which are treated or deemed as interest under applicable law.

2. PROMISE TO PAY. For value received, Borrower promises to pay to Lender or order, at Lender’s address set forth hereinabove or at such other location as Lender may designate in writing to Borrower, the principal sum of Nine Hundred Thousand and No/100 Dollars ($900,000.00) plus interest on the unpaid principal balance of this Note from April 13, 2009, until this Note is repaid in full at the applicable rates set forth hereinbelow.

3. INTEREST ACCRUAL. The outstanding principal balance of this Note shall accrue interest from April 13, 2009, until this Note is fully repaid at the Note Rate or the Default Rate,

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whichever is applicable at the time in question. During all periods when there is no default under the terms of the Loan, the outstanding principal balance of this Note shall accrue interest at the Note Rate. During all periods when there is a default under the terms of the Loan, the outstanding principal balance of this Note shall accrue interest at the Default Rate. Accrued interest on the outstanding principal balance of this Note shall be computed on the basis of a three hundred sixty (360) day year and shall accrue on the actual number of days elapsed for any period in which interest is being calculated, provided that if computing interest using a three hundred sixty (360) day year causes interest to exceed the Maximum Lawful Rate, interest shall be calculated using a three hundred sixty-five (365) day year, or three hundred sixty-six (366) day year, as applicable. In computing the number of days during which interest accrues, the day on which funds are initially advanced shall be included regardless of the time of day such advance is made, and the day on which funds are repaid shall be included unless repayment is credited prior to the close of business on the business day received.

4. INTEREST PROVISIONS.

A. Savings Clause . It is expressly stipulated and agreed to be the intent of Lender and Borrower at all times to comply strictly with the applicable Texas law governing the maximum rate or amount of interest payable on the indebtedness evidenced by this Note (or applicable United States federal law to the extent that it permits Lender to contract for, charge, take, reserve or receive a greater amount of interest than under Texas law). If the applicable law is ever judicially interpreted so as to render usurious any amount (i) contracted for, charged, taken, reserved or received pursuant to this Note, any of the other Loan Documents or any other communication or writing by or between Lender and Borrower related to the transaction or transactions that are the subject matter of the Loan Documents, (ii) contracted for, charged, taken, reserved or received by reason of Lender’s exercise of the option to accelerate the maturity of this Note, or (iii) Lender will have received by reason of any voluntary prepayment by Borrower of this Note, then it is Lender’s and Borrower’s express intent that all amounts charged in excess of the Maximum Lawful Rate automatically shall be canceled, ab initio , and all amounts in excess of the Maximum Lawful Rate theretofore collected by Lender shall be credited on the principal balance of this Note (or, if this Note has been or would thereby be paid in full, refunded to Borrower), and the provisions of this Note and the other Loan Documents immediately shall be deemed reformed and the amounts thereafter collectible hereunder and thereunder reduced, without the necessity of the execution of any new document, so as to comply with the applicable law but so as to permit the recovery of the fullest amount otherwise called for hereunder and thereunder; provided, however, if this Note has been paid in full before the end of the stated term of this Note, then Lender and Borrower agree that Lender shall, with reasonable promptness after Lender discovers or is advised by Borrower that interest was received in an amount in excess of the Maximum Lawful Rate, refund such excess interest to Borrower. Borrower hereby agrees that, as a condition precedent to any claim seeking usury penalties against Lender, Borrower will provide written notice to Lender, advising Len