EXHIBIT 10.4

                                Schedule 1.02(a)
                                       to
                            Stock Purchase Agreement

                                   LEXON, INC.
                                 PROMISSORY NOTE

$150,000                                                         Tulsa, Oklahoma
                                                                January 28, 2000

         FOR VALUE RECEIVED,  LEXON, INC. hereby promises to pay to the order of
UTEK CORPORATION ("UTEK") the principal amount of One Hundred and Fifty Thousand
and no/100 Dollars ($150,000) plus interest as provided herein.

         1.  Maturity.  This Note and all accrued but unpaid  interest  shall be
paid in 3 equal consecutive monthly principal payments of $50,000 each beginning
on or before April 30, 2000 and  continuing on or before May 31, 2000, and on or
before June 30, 2000, respectively.

         2. Interest  Rate.  This Note shall bear interest until maturity at the
rate of 10% per annum and thereafter the unpaid  principal  balance of this Note
shall bear interest at the rate of 12% per annum.

         3. Maximum Interest Rate.  Notwithstanding  any provision herein,  UTEK
shall never be  entitled to receive,  collect or apply as interest on any amount
owed  hereunder  any amount in excess of the  maximum  lawful  rate of  interest
permitted  to be charged  by any  applicable  law.  In the event UTEK shall ever
receive,  collect  or apply as  interest  any  amount in  excess  of any  amount
permitted to be received under  applicable law, all such excess amounts shall be
applied as of the date  received to the  reduction  of the  principal  amount of
indebtedness hereunder. After payment of the indebtedness in full, all remaining
excess amounts paid shall forthwith be returned within five (5) days to LEXON.

         4. Permissive  Prepayment.  This Note and all  indebtedness  arising in
connection herewith may be prepaid at any time and from time to time in whole or
in part by LEXON without premium, penalty or other charges or fees whatsoever.

         5.  Application  of  Payments.  All payments  against the  indebtedness
arising under this Note shall be applied first to costs of collection, second to
accrued but unpaid interest and the balance to unpaid principal.

         6. Collateral.  The  indebtedness  evidenced by this Note is secured by
that certain Pledge and Security Agreement  ("Pledge  Agreement") given by LEXON
in favor of UTEK of even date herewith.  This Note is non-recourse  except as it
relates to the Collateral and the Pledged Shares under the Pledge Agreement.

         7.  Events of Default.  At the option of UTEK , this Note shall  become
immediately  due and payable upon the occurrence and during the  continuation of
the following events of default:

               (a) LEXON fails to pay  principal or interest  within 15 business
days after LEXON receives written notice of such payment default;

               (b) LEXON shall:

                    (1)  Be adjudicated a bankrupt or insolvent; or

<PAGE>

                    (2)  Admit in writing its  inability  to pay  LEXON's  debts
                         generally as they become due; or

                    (3)  Apply for or consent to the  appointment of a receiver,
                         trustee,   or   liquidator   of  LEXON  or  of  all  or
                         substantially all of LEXON's assets; or

                    (4)  File a voluntary  petition in  bankruptcy or a petition
                         or an answer seeking  reorganization  or an arrangement
                         with  creditors or take  advantage of or seek any other
                         relief    under   any    bankruptcy,    reorganization,
                         rearrangement, debtor's relief, or other insolvency law
                         now or hereafter existing; or

                    (5)  File an answer  admitting the material  allegations of,
                         or  consenting  to,  or  failure  to  answer  timely  a
                         petition   filed  against  LEXON  in  any   bankruptcy,
                         reorganization,   rearrangement,  debtor's  relief,  or
                         other insolvency proceedings; or

                    (6)  Institute  or  voluntarily  be or become a party to any
                         other  judicial   proceedings   intended  to  effect  a
                         discharge of all or substantially all of LEXON's debts,
                         in whole or in part, or a postponement  of the maturity
                         or the  collection  thereof,  or a suspension of any of
                         the rights or powers granted hereby; or

                (c) An order,  judgment, or decree shall be entered by any court
of competent  jurisdiction  approving a petition seeking reorganization of LEXON
or  appointing  a  receiver,  trustee,  or  liquidator  of  LEXON  or of  all or
substantially  all of its  assets,  and such order,  judgment,  or decree is not
permanently stayed or reversed within sixty (60) days after entry thereof; or

                (d) A petition is filed against LEXON seeking reorganization, an
arrangement   with  creditors,   or  any  other  relief  under  any  bankruptcy,
reorganization,  rearrangement,  debtor's relief, or other insolvency law now or
hereafter  existing,  and such petition is not discharged within sixty (60) days
after the filing thereof.

         If one or more events of default shall occur and be  continuing,  after
the expiration of any grace or curative period provided herein, UTEK may, at its
option,  declare the entire  indebtedness  arising hereunder due and payable and
may proceed to protect and enforce any and all rights to enforce  payment of all
indebtedness  arising  hereunder at law or in equity.  All rights,  remedies and
powers  conferred  upon UTEK herein shall be cumulative and not exclusive of any
other  rights,  remedies or powers.  No delay or omission to exercise any right,
remedy  or power  shall  impair  any  such  right,  remedy  or power or shall be
construed  to be a  waiver  of any  event  of  default  or any  acquiescence  or
forbearance with respect thereto.  Any right,  remedy or power granted hereunder
or  applicable  under  law or in  equity  may be  exercised  from  time to time,
independently  or  concurrently.  No waiver of any event of default shall extend
any other  subsequent  event of  default.  No single or partial  exercise of any
right, remedy or power shall preclude the exercise of any other right, remedy or
power or the further exercise thereof.

         8.  Governing  Law.  This  Note  has been  executed  and  delivered  in
Hillsborough  County,  Florida  and  shall  be  governed  by  and  construed  in
accordance with the laws of the State of Florida. UTEK expressly agrees that the
courts of Florida shall have  jurisdiction  over all  proceedings  in connection
herewith,  and LEXON agrees that for purposes of  enforcement  of UTEK 's rights
and


                                       2

<PAGE>
remedies  hereunder,  venue and personal  jurisdiction  are proper in the courts
situated  in  Hillsborough  County,  Florida.  LEXON  waives any right to a jury
trial.

         9.  Severability.  In the event  any  provision  of this Note  shall be
declared by a court of competent jurisdiction to be unenforceable or invalid for
any  reason  whatsoever,  the  remaining  provisions  of this Note  shall not be
affected  thereby  and all such  remaining  provisions  shall be enforced to the
maximum extent permitted by law.

         10. Costs of Collection. If this Note or any portion hereof is not paid
when due, after  expiration of all curative  periods,  LEXON promises to pay all
reasonable  costs of  collection,  including but not limited to, all  reasonable
attorneys' fees, court costs and reasonable  expenses  incurred in good faith by
UTEK in order to obtain  prompt,  punctual and proper  payment of all amounts of
indebtedness arising hereunder.

         11. Waiver. LEXON and all other parties now or hereafter liable for the
payment of the indebtedness arising hereunder,  whether as endorser,  guarantor,
surety or otherwise,  waive  demand,  presentment,  diligence in collecting  and
consent to all extensions which from time to time may be granted.

         12.  Binding  Effect.  This  Note  and  all  the  covenants,  promises,
obligations  and  agreements  of LEXON and all rights,  powers,  privileges  and
entitlements  of UTEK  shall be binding  upon and inure to the  benefit of their
respective successors, legal representatives, and permitted assigns.

         13.  Currency  and Place of  Payment.  All  payments of  principal  and
interest  arising in connection  with this Note shall be made in lawful currency
of the United States of America and shall be paid to UTEK at 202 Wheeler Street,
Plant City,  Florida 33566 or such other place as UTEK shall  instruct  LEXON in
writing.

                                             LEXON, INC.


                                             By  /s/ GIFFORD MABIE
                                             Gifford Mabie, President

                                       3