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                                                                   EXHIBIT 10.28

                          COMMERCIAL LEASE - TRIPLE NET

1. PARTIES. This Lease is made effective November 1, 2002, by and between the
following parties:

(1)   IMARx Investments L.L.C., an Arizona Limited Liability Company, (herein
      called "Landlord" or "Lessor"), and

(2)   IMARx Therapeutics, Inc., a Delaware corporation (herein called "Tenant"
      or "Lessee").

2. PREMISES. Landlord hereby leases to Tenant and Tenant leases from Landlord,
upon all of the conditions set forth herein, the premises situate in the County
of Pima, State of Arizona, with address of (and commonly known as) 1635 East
18th Street, Tucson, Arizona 85710 ("the premises"), being a commercial
industrial building of approximately 6,200 square feet in size and surrounding
real property for access, landscaping and parking which is more precisely
described on the "Legal Description" attached hereto as Exhibit A.

3. TERM. The basic term of this Lease shall be for approximately six (6) years
commencing on November 1, 2002, and ending on October 31, 2008, unless sooner
terminated or extended pursuant to any provision hereof. Specific options to
extend are contained in Paragraph 40, hereof.

4. BASIC RENT.

            4.1 Monthly Fixed Rent. Tenant shall pay to Landlord as fixed rent
for the Premises, monthly payments of FOUR THOUSAND EIGHT HUNDRED SEVENTY FOUR
DOLLARS ($4,874.00) each, in advance, without deduction, off-set or demand, on
the first day of each month of the term hereof with the initial month's rent
being prorated. The basic monthly rental shall be adjusted at the end of a three
(3) year period to reflect any increase in the consumer price index (all items)
published by the U.S. Labor Department for the first month of the three year
period compared to the last month of the lease term. Rent shall be payable in
lawful money of the United States to Landlord at the address stated herein or to
such other persons or at such other places as Landlord may designate in writing
from time to time.

            4.2 Rental Taxes. As additional rent, Tenant further agrees to pay
to Landlord, together with each basic, periodic rental payment, the amount of
any excise, sales or transaction privilege tax imposed or levied by any
government or governmental agency upon Landlord on account of this Lease, or of
the rentals paid hereunder by Tenant, or of any other payments made or
obligations discharged or benefits conferred by Tenant hereunder, including
without limitation, payments of Tenant's costs of insurance under Paragraph 10,
real property taxes under Paragraph 6 and other maintenance expenses under
Paragraph 5. Tax calculations and impositions will be subject to applicable
changes in local and state tax ordinances.

5. ADDITIONAL RENT: AND OTHER MAINTENANCE EXPENSES. In order that the fixed rent
shall be absolutely net to Landlord, Tenant covenants to pay, as additional
rent, all real estate taxes (see Paragraph 6), and all other operating expenses,
respecting the Premises, including the following:


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(1)   Various utilities costs, janitorial and other maintenance costs, insurance
      costs, real property tax impositions, and any other operating costs.
      Accordingly, Tenant shall pay to or as directed by Landlord the amount of
      such operating expenses reasonably allocated to or attributable to the
      Premises within ten (10) days after each periodic invoicing or other
      billing received by Tenant therefor from either the party providing such
      services or Landlord, as the case may be;

(2)   Additionally,

(a)   Tenant shall pay to Landlord, within a reasonable time after written
      demand therefor by Landlord but before any fine, penalty, interest or cost
      may be added thereto for nonpayment thereof, all public charges with
      respect to the Premises, including, but not limited to, water and sewer
      use charges and betterment assessments, as well as real estate taxes
      (pursuant to Paragraph 6), business privilege taxes (pursuant to Paragraph
      4.2), and personal property taxes (pursuant to Paragraph 6.3).

(b)   Tenant shall pay directly to the proper authorities charged with
      collection thereof all charges for water, sewer, gas, electricity,
      telephone, and any other power, utilities, or services used for consumed
      on the premises; Tenant shall make its own arrangements for such utilities
      and Landlord shall be under no obligation to furnish any utilities to the
      Premises and shall not be liable for any interruption or failure in the
      supply of any such utilities to the Premises;

Tenant agrees to pay for janitorial service and any other maintenance services
for or repairs of the Premises, all in accordance with the provisions of this
Lease (including Paragraph 9).

(c)   Tenant shall furnish to Landlord, at Landlord's written request, for
      Landlord's inspection, within thirty (30) days after the date any amount
      is payable by Tenant, as provided in Paragraph 5, official receipts or
      other proof satisfactory to Landlord evidencing such payment.

6. REAL PROPERTY TAXES.

            6.1 Payment of Taxes. Within ten (10) days after written demand by
Landlord, Tenant shall pay to Landlord the "Real Property Tax", as defined in
Paragraph 6.2, applicable to the Premises during the term of this Lease. If any
such taxes shall cover any period of time prior to or after the expiration of
the term hereof, Tenant's share of such taxes shall be equitably prorated to
cover only the period of time within the applicable tax fiscal year when this
Lease was in effect.

            6.2 Definition of "Real Property Tax". As used herein, the term
"Real Property Tax" shall include any form of real estate tax or assessment, be
it ad valorem, general, special ordinary or extraordinary, and any license fee,
commercial rental tax, improvement bond or bonds, levy or tax (other than
inheritance, personal income or estate taxes) imposed on or reasonably
attributable to the Premises by any authority having the direct or indirect
power to tax, including any city, state or federal government, or any school,
agricultural, sanitary, fire, street, drainage or other improvement district
thereof. The Term "Real Property Tax" shall also include any tax, fee, levy,
assessment or charge (i) in substitution of, partially or totally, any tax, fee,
levy assessment or charge hereinabove included within the definition of "Real
Property Tax", or (ii) the nature of which was hereinbefore included within the
definition of "Real

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Property Tax", or (iii) which is imposed by reason of this transaction, any
modifications or changes hereto or any transfers hereof.

6.3 Personal Property Taxes.

                  (a) Tenant shall pay prior to delinquency all taxes assessed
against and levied upon trade fixtures, furnishings, furniture, equipment and
all other personal property of Tenant contained in the Premises or elsewhere.
Whenever possible, Tenant shall cause said trade fixtures, furnishings,
furniture, equipment and all other personal property to be assessed and billed
separately from the Real Property of Landlord.

                  (b) If any of Tenant's personal property shall be assessed
with Landlord's Real Property, Tenant shall pay Landlord the taxes attributable
to Tenant within ten (10) days after receipt of a written statement from
Landlord setting forth the taxes applicable to Tenant's Property. Landlord's
reasonable determination thereof, in good faith shall be conclusive.

7. SECURITY DEPOSIT. Tenant shall make the following deposit with Landlord upon
execution hereof as security for Tenant's faithful performance of Tenant's
obligations hereunder: Cash in the amount of $3,508.96, to be held by Landlord.

If Tenant fails to pay rent or other charges due and payable hereunder, or
otherwise defaults with respect to any provision of this Lease, then, after
10-days' written notice of the default and failure by Tenant to cure within said
10-day period, Landlord may use, apply or retain all or any portion of said
deposit for the payment of any rent, damages or other charge in default. If
Landlord so uses or applies all or any portion of said deposit, the Tenant
shall, within ten (10) days after written demand therefore deposit cash with
Landlord in an amount sufficient to restore said deposit to the full amount
hereinabove stated ($3,508.96). Tenant's failure to do so shall be a material
breach of this Lease. Landlord shall be required to keep said deposit separate
from its general accounts and in a separate interest-bearing account. At the end
of each calendar year any accrued interest shall be paid to Tenant, if not
needed to bring account up to full balance. If Tenant performs all of Tenant's
obligations hereunder, said deposit, or so much thereof as has not theretofore
been applied by Landlord shall be returned, together with any interest accrued
on it, to Tenant at the expiration of the term hereof (and once Tenant has
vacated the Premises). No trust relationship is created herein between Landlord
and Tenant with respect to said Security Deposit.

8. USE. The Premises shall be used and occupied only commercial offices and
testing and production of pharmaceutical products, including any other uses
which are in compliance with zoning restrictions governing the use of Premises,
and for no other purpose. Landlord expressly disclaims any/all representations
and warranties regarding the lawfulness of Tenant's intended use or occupation
of the Premises. It is Tenant's responsibility to determine and comply with all
applicable covenants, conditions and restrictions and all applicable zoning
ordinances or other ordinances, regulations, requirements, stipulations and
conditions affecting the use of occupancy of the Premises.

      8.2 Compliance with Law.

                  (a) Tenant shall, at Tenant's expense, comply promptly with
all applicable laws, statutes, ordinances, rules, regulations, orders,
covenants, restrictions of record, and requirements in effect during the term or
any part of the term hereof, regulating Tenant's operation on and occupancy and
use of the Premises including but not limited to compliance

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with all environmental laws. Environmental laws shall mean any and all federal
and state laws and regulations that concern the regulation and/or protection of
the environment, including the ambient air, ground water, surface water, noise,
vibration, asbestos, hazardous materials, and land use, including substrata
land. Tenant shall not use or permit the use of the Premises, including placing
loads on any floor or wall, in a manner for which the premises were not
designed, engineered or constructed. Tenant shall not place a load upon any
floor or wall exceeding the design engineering criteria, which such floor or
wall was designed to carry and/or which is prescribed by any law or regulation
in existence during the term of this Lease. Tenant may request in writing
Landlord's approval of any or all of Tenant's trade fixtures and equipment for
compliance with the design engineering criteria for the Premises and Landlord
shall reply to Tenant's request within a reasonable period of time. Tenant
hereby indemnifies Landlord against liability for any of the above items. Tenant
shall not use nor permit the use of the Premises in any manner that will create
waste or a nuisance.

            8.3 Condition of Premises. Unless otherwise specifically provided in
this Lease, Tenant hereby accepts the Premises in their "AS IS" condition
including any and all defects, latent or otherwise, existing as of the Lease
commencement date or the date that Tenant takes possession of the Premises,
whichever is earlier, subject to all applicable zoning, municipal, county and
state laws, ordinances and regulations governing and regulating the use of the
Premises, and any covenants or restrictions of record, and accepts this Lease
subject thereto and to all matters disclosed thereby and by any exhibits
attached hereto. Tenant acknowledges that Landlord has made no representation or
warranty as to the present or future suitability of the Premises for Tenant's
use or the conduct of Tenant's business.

9. MAINTENANCE, REPAIRS AND ALTERNATIONS.

            9.1 Tenant's Obligations. Tenant shall maintain, replace and keep in
good order, condition and repair the Premises and every part thereof, which is
nonstructural (whether or not such portion of the Premises requiring repair, or
the means of repairing the same are reasonably or readily accessible to Tenant,
and whether or not the need for such repairs occurs as a result of Tenant's use,
or any prior use, the elements or the age of such portion of the Premises),
including, without limiting the generality of the foregoing, the maintenance and
replacement of all plumbing, heating, air conditioning (Tenant shall procure and
maintain, at Tenant's expense, an air conditioning system maintenance contract),
ventilating, electrical, lighting facilities and equipment within the Premises,
fixtures, walls (interior and exterior), ceilings, roofs (interior and
exterior), windows, doors, plate glass and skylights located within the
Premises, and all landscaping, driveways, parking lots, sidewalks, fences and
signs located on the Real Property which are reserved for Tenants use. Tenant
shall not be responsible for replacement of any structural part of the building.

            9.2 Surrender. On the last day of the term hereof, or on any sooner
termination, Tenant shall surrender the Premises to Landlord in the same
condition as when received, ordinary wear and tear excepted, clean and free of
damage or debris. Tenant shall repair any damage to the Premises and/or the Real
Property occasioned by the installation or removal of Tenant's trade fixtures,
furnishings and equipment. Notwithstanding anything to the contrary otherwise
stated in this Lease, Tenant shall leave the power panels, electrical
distribution systems, lighting fixtures, space heaters, air conditioning,
plumbing, doors and fencing on the Premises which will belong to the Landlord in
good operating condition.

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            9.3 Landlord's Rights. If Tenant fails to perform Tenant's
obligation under this Paragraph, or under any other paragraph of this Lease,
Landlord may at its option (but shall not be required to) enter upon the
Premises after ten (10) days prior written notice to Tenant (except in the case
of urgency, in which case no notice shall be required), perform such obligation
on Tenant's behalf and put the same in good order, condition and repair, and the
cost thereof, together with interest thereon (at two (2) points over the prime
rate as set and announced by the Wall Street Journal from time to time), shall
become due and payable on demand as additional rental to Landlord.

            9.4 Landlord's Obligations. Except for the obligations of Landlord
under Paragraph 11 (relating to destruction of the Premises) and under Paragraph
15 (relating to condemnation of the Premises), it is intended by the parties
hereto that Landlord shall have no obligation, in any manner whatsoever, to
repair or maintain the Premises or any part thereof, or the Real Property, or
any equipment on the Premises, which are nonstructural, or which obligations are
intended to be those of the Tenant under Paragraph 9.1 hereof. Tenant expressly
waives the benefit of any statute of law now or hereinafter in effect which
would otherwise afford Tenant the right to make repairs at Landlord's expense or
to terminate this Lease because of Landlord's failure to keep the Premises in
good order, condition and repair. Notwithstanding the foregoing, should Landlord
receive any warranty or guaranty respecting any material, equipment, or
workmanship, and should such warranty or guaranty be applicable to portions of
the Premises which Tenant is liable to repair and maintain (as required
hereunder), Landlord shall, upon Tenant's request, assign and transfer such
warranty or guaranty to Tenant for Tenant's use and benefit.

            9.5 Alterations and Additions.

                  (a) Tenant shall not, without Landlord's prior written
consent, which shall be given if reasonable, make any alterations, improvements,
additions or Utility Installation in, on or about the Premises. Tenant shall
make no change or alteration to the exterior of the Premises, nor to the Real
Property, without Landlord's prior written consent. As used in this Paragraph
9.5 the term "Utility Installation" shall mean carpeting, window covering, air
lines, power panels, electrical distribution systems, lighting fixtures, space
heaters, air conditioning, plumbing or fencing. Landlord may not require that
Tenant remove any or all of said alterations, improvements, additions or Utility
Installations at the expiration of the term. Landlord may require Tenant to
provide Landlord, at Tenant's sole cost and expense, a lien and completion bond
in an amount equal to one and one-half times the estimated cost of such
improvements, to insure Landlord against any liability for mechanic's and
material men's liens and to insure completion of the work. Landlord may impose
reasonable conditions from time to time with respect to the improvements to
which Landlord may consent, including without limitation, compliance with all
laws, including environmental laws, regulations, ordinances and -requirements of
governments or governmental agencies, and the time and manner in which such work
shall be accomplished. Should Tenant make any alterations, improvements,
additions or Utility Installation without the prior approval of Landlord,
Landlord may require that Tenant remove any or all of the same.

                  (b) Any alteration, improvement, addition, or Utility
Installation in or about the Premises that Tenant shall desire to make and which
requires the consent of the Landlord shall be presented to Landlord in written
form, with proposed detailed plans, and Landlord shall respond to Tenant on the
matter within fifteen (15) days after Landlord's receipt of the plans and
specifications and other information requested by Landlord in order to make an
informed decision. If Landlord shall give its consent, the consent shall be
deemed conditioned upon Tenant acquiring applicable permit(s) to do so from
appropriate governmental agencies, the

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furnishing of a copy thereof to Landlord prior to the Commencement of the work
and the compliance by Tenant with all conditions of said permit in a prompt and
expeditious manner, and compliance by Tenant with all laws, rules, regulations,
recommendations and/or applicable requirements of any government or governmental
agency.

                  (c) Tenant shall pay, when due, all claims for labor,
professional services and materials furnished, or alleged to have been furnished
to or for Tenant at (or for use in) the Premises, which claims are or may be
secured by any mechanic's or material men's lien against the Premises or any
interest therein. Tenant shall give Landlord not less than ten (10) days' notice
prior to the commencement of any work in the Premises, and Landlord shall have
the right to post notices of non-responsibility in or on the Premises as
provided by law. If Tenant shall, in good faith, contest the validity of any
such lien, claim or demand, then Tenant shall, at its sole expense defend itself
and Landlord against same and shall pay and satisfy any such adverse judgment
that may be rendered thereon before the enforcement thereof against the Landlord
or the Premises, upon the condition that if Landlord shall require, Tenant shall
furnish to Landlord a surety bond satisfactory to Landlord in an amount
sufficient to cover Landlord against liability on account of such contested
lien, claim or demand, and indemnifying Landlord against liability for the same,
and holding the Premises free from the effect of such lien or claim. In
addition, Landlord may require Tenant to pay Landlord's attorney fees and costs
incurred on account of participation in such action, if Landlord determines in
its discretion to do so and does so.

                  (d) Unless Landlord requires their removal, as set forth in
Paragraph 9.5(a), all alterations, improvements, additions, and Utility
Installations (unless such Utility Installations constitute trade fixtures of
Tenant), which may be made on the Premises, shall become the property of
Landlord and remain upon and be surrendered with the Premises at the expiration
of the term. Notwithstanding the foregoing provision, Tenant's furniture,
machinery and equipment shall remain the property of Tenant and may be removed
by Tenant subject to the provisions of Paragraph 9.2.

10. INSURANCE INDEMNITY. It is understood and agreed that Tenant shall be
obliged to pay for insurance coverage, including property casualty and public
liability insurance, with respect to the Premises, as specified in Paragraph
5(1) above. In case such insurance coverage is deemed inadequate by Landlord at
any time in its reasonable discretion, Tenant shall be obliged to provide
insurance coverage pursuant to the following Paragraphs 10.1 through 10.4.

            10.1 Liability Insurance. Tenant shall, at Tenant's expense, obtain
and keep in force during the term of this Lease and during Tenant's occupancy of
the Premises a policy of comprehensive general liability insurance with at least
$1,000,000 combined single limit for bodily injury (including death and property
damage), covering the Premises, and Tenant's use and occupancy thereof against
all claims on account of bodily injury or death and property damage occurring
upon, in or about such areas or in connection with the ownership, maintenance,
use and/or occupancy of such areas. Landlord, and, at Landlord's option, any
mortgagee of Landlord, shall be named as insured or as an additional insured
under the policy. The limits of said insurance shall not, however, limit the
liability of Tenant hereunder.

            10.2 Property Casualty Insurance. Tenant shall obtain and keep in
force during the term of this Lease a policy or policies of insurance covering
loss or damage to the Premises in the amount of the full replacement value
thereof, as the same may exist from time to time, but in no event less than the
total amount required by lenders having liens on the Premises, against all
perils included within the classification of fire, extended coverage, vandalism,
malicious

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mischief and flood (in the event same is required by a lender having a lien on
the Premises). Landlord shall be named as insured (or an additional insured) on
the policy. Said insurance shall provide for payment of loss thereunder to
Landlord or to the holders of mortgages or deeds of trust on the Premises.

            10.3 Insurance Policies. Insurance required hereunder shall be in
companies holding a "General Policyholders Rating" of at least B-plus, or such
other rating as may be required by a lender having a lien on the Premises, as
set forth in the most current issue of "Best's Insurance Guide". Tenant shall
provide to Landlord copies of insurance certificates naming the insured parties
and evidencing the existence and the amounts of the insurance required in this
Paragraph 10, promptly upon execution of this Lease. No such policy shall be
cancelable or subject to reduction of coverage or other modification except
after thirty (30) days prior written notice to Landlord. Tenant shall, at lease
thirty (30) days prior to the expiration of such policies, furnish Landlord and
any mortgagee of Landlord named as an insured with renewals certificates, or
landlord may, but shall not be obligated to, order such insurance and charge the
cost thereof to Tenant, which amount shall be payable by Tenant upon demand.
Tenant shall not do or permit to be done anything which shall invalidate the
insurance policies referred to in this section 10. If Tenant does or permits to
be done anything which shall increase the costs of the insurance policies
referred to in Paragraph 10.2, then Tenant shall forthwith upon Landlord's
demand pay such additional cost, or reimburse Landlord for any additional
premium payable by it which is attributable to any act or omission or operation
or Tenant causing such increase in the cost of insurance.

            10.4 Waiver of Subrogation. Tenant and Landlord each hereby release
and relieve the other, and waive their entire right of recovery against the
other for loss or damage arising out of or incident to the perils insured
against under Paragraph 10.2, which perils occur in, on or about the Premises,
whether due to the negligence of Landlord or Tenant or their agents, employees
contractors and/or invitees but only to the extent that insurance policies then
in effect permit such waiver and only to the extent of the coverage provided by
such insurance policies. Tenant and Landlord shall, upon obtaining the policies
of insurance required hereunder, give notice to the insurance carrier or
carriers that the foregoing mutual waiver of subrogation is contained in this
Lease.

            10.5 Indemnity. Tenant shall indemnify and hold harmless Landlord
from and against any and all claims arising from Tenant's (or Tenant's agents',
servants', employees' or contractors') use or occupancy of the Premises, or from
the conduct of Tenant's business or from any activity, work or things done,
permitted or suffered by Tenant (or Tenant's agent, servants, employees or
contractors) in or about the Premises and shall further indemnify and hold
harmless Landlord from and against any and all claims arising from any breach or
default in the performance of any obligation on Tenant's part to be performed
under the terms of this Lease, or arising from any negligence of the Tenant, or
any of Tenant's agents, contractors or employees, and from and against all
costs, attorneys' fees, expenses and liabilities incurred in the defense of any
such claim or any action or proceeding brought thereon; and in case any action
or proceeding brought against Landlord by reason of such claim, Tenant (upon
notice from Landlord) shall defend the same at Tenant's expense, by counsel
satisfactory to Landlord. For valuable, sufficient consideration, Tenant, hereby
assumes all risk of damage to property or injury to persons in, upon or about
the Premises arising from any cause (except Landlord's negligence), and Tenant
hereby waives all claims with respect thereto against Landlord.

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            Tenant shall indemnify and hold harmless Landlord from and against
any and all liability, claims or actions for injury, liability, or damage to
persons or property, and any and all claims or actions brought by any person,
firm, governmental body, or other entity, including reasonable legal fees and
expenses, alleging or resulting from or arising from or in connection with
contamination of or adverse affects on the Premises, the environment, or any
violation of any Environmental Law or other statute, ordinance, rule,
regulation, judgment or order of any governmental or judicial entity, and from
and against any damages, liabilities, costs, and penalties assessed as a result
of any activity or operation on the Premises during the term of this Lease.
Tenant's obligations or liabilities under this Paragraph shall survive the
term(s) of this Lease, termination of this Lease or termination of Tenant's
occupancy of the Real Property.

            10.6 Exemption of Landlord Liability. Tenant hereby agrees that
Landlord shall not be liable for injury to Tenant's business or any loss of
income therefrom or for damage to the goods, wares, merchandise or other
property of Tenant, Tenant's employees, invitees, customers or any other person
in or about the Premises, nor shall Landlord be liable for injury to the person
of Tenant, Tenant's employees, agents or contractors, whether such damage or
injury is caused by or results from fire, steam, electricity, gas, water or
rain, or from the breakage, leakage, obstruction or other defects of pipes,
sprinklers, wires, appliances, plumbing, air conditioning or lighting fixtures,
or from any other cause, whether the said damage or injury results from
conditions arising upon the Premises or from other sources or places and
regardless of whether the cause of such damage or injury or the means of
repairing the same is inaccessible to Tenant unless caused by Landlord's
negligence.

11. DAMAGE OR DESTRUCTION.

            11.1 Definitions.

                  (a) "Premises Partial Damage" shall herein mean damage or
destruction to the Premises to the extent that the cost of repair is less than
twenty percent (20%) of the then replacement cost of the Premises.

                  (b) "Premises Total Destruction" shall herein mean damage or
destruction to the Premises to the extent that the cost of repair is twenty
percent (20%) or more of the then replacement cost of the Premises.

                  (c) "Insured Loss" shall herein mean damage or destruction
which was caused by an event required to be covered by the insurance described
in Paragraph 10, and sufficient insurance proceeds are available for repairs
free of any claim of the holder of a mortgage or deed of trust on the Premises.

            11.2 Partial Damage - Insured Loss. Subject to the provisions of
Paragraphs 11.4, 11.5 and 11.6, if at any time during the term of this Lease,
there is damage which is an Insured Loss and which falls into the classification
of Premises Partial Damage, then Landlord shall, unless Landlord's mortgagee
requires otherwise, at Landlord's expense, repair such damage (but not Tenant's
fixtures, equipment or tenant improvements unless the same have become a part of
the Premises pursuant to Paragraph 9 hereof) as soon as reasonably possible, and
this Lease shall continue in full force and effect. If the insurance proceeds
received by Landlord are not sufficient to effect such repair, Landlord shall
give notice to Tenant of the amount required in addition to the insurance
proceeds to effect such repair. Tenant shall contribute the required amount to
Landlord within ten (10) days after Tenant has received notice from Landlord of
the shortage in

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the insurance. When Tenant shall contribute such amount to Landlord, Landlord
shall make such repairs as soon as reasonably possible and this Lease shall
continue in full force and effect. Tenant shall in no event have any right to
reimbursement for any such amount so contributed.

            11.3 Partial Damage - Uninsured Loss. Subject to the provisions of
Paragraphs 11.4, 11.5, and 11.6, if at any time during the term of this Lease
there is damage which is not an Insured Loss and which falls within the
classification of Premises Partial Damage, unless caused by a negligent or
willful act of Tenant (in which event Tenant shall make the repairs at Tenant's
expense), Landlord may at Landlord's option either (i) repair such damage as
soon as reasonably possible at Landlord's expense, in which event this Lease
shall continue in full force and effect, or (ii) give written notice to Tenant
within thirty (30) days after the date of the occurrence of such damage of
Landlord's intention to cancel and terminate this Lease, as of the date of the
occurrence of such damage. In the event Landlord elects to give such notice of
Landlord's intention to cancel and terminate this Lease, Tenant shall have the
right within ten (10) days after the receipt of such notice to give written
notice to Landlord of Tenant's intention to repair such damage at Tenant's
expense without reimbursement from Landlord, in which event this Lease shall
continue in full force and effect, and Tenant shall proceed to make such repairs
as soon as reasonably possible. If Tenant does not give such notice within such
ten (10) day period this Lease shall be cancelled and terminated as of the date
of the occurrence of such damage.

            11.4 Total Destruction. If at any time during the term of this Lease
there is damage, whether or not an Insured Loss, including destruction required
by any authorized public authority, which falls into the classification of
Premises Total Destruction, this Lease shall automatically terminate as of the
date of such total destruction.

            11.5 Damage Near End of Term.

                  (a) If at any time during the last year of the term of this
Lease, there is damage (whether or not an Insured Loss) which falls within the
classification of Premises Partial Damage, Landlord may at Landlord's option
cancel and terminate this Lease as of the date of occurrence of such damage by
giving written notice to Tenant of landlord's election to do so within thirty
(30) days after the date of occurrence of such damage.

                  (b) Notwithstanding Paragraph 11.5(a), in the event that
Tenant has an option to extent or renew this Lease, and the time within which
said option may be exercised has not yet expired, Tenant shall exercise such
option, if it is to be exercised at all, no later than twenty (20) days after
the occurrence of any Insured Loss falling within the classification of Premises
Partial Damage during the last year of the term of this Lease. If Tenant duly
exercises such option during said twenty (20) day period, Landlord shall, at
Landlord's expense repair such damage as soon as reasonably possible and this
Lease shall continue in full force and effect. If Tenant fails to exercise such
option during said twenty (20) day period then Landlord may, at Landlord's
option, terminate and cancel this Lease as of the expiration of said twenty (20)
day period by giving written notice to Tenant of Landlord's election to do so
within ten (10) days after the expiration of said twenty (20) day period,
notwithstanding any term or provision in the grant of option to the contrary.

            11.6 Abatement of Rent; Tenant's Remedies.

                  (a) In the event of damage described in Paragraphs11.2 or
11.3, and Landlord or Tenant repairs or restores the Premises pursuant to the
provisions of this Paragraph 11, the rent payable hereunder, for the period
during which such damage, repair or restoration

                                       9

<PAGE>

continues, shall be abated in proportion to the degree to which Tenant's use of
the Premises is prevented. Except for abatement of rent, if any, Tenant shall
have no claim against Landlord for any loss or damage including, without
limitation, loss of business suffered by reason of any such damage, destruction,
repair or restoration.

                  (b) If Landlord shall be obligated to repair or restore the
Premises under the provisions of this Paragraph 11 and shall not commence such
repair or restoration within ninety (90) days after such obligations shall
occur, Tenant may at Tenant's option, cancel and terminate this Lease by giving
Landlord written notice of Tenant's election to do so at any time prior to the
commencement of such repair or restoration. In such event, this Lease shall
terminate as of the date of such notice.

            11.7 Termination - Advance Payments. Upon termination of this Lease
pursuant to this Paragraph 11, an equitable adjustment shall be made in advance
rental payments, if any, made by Tenant to Landlord. Landlord shall, in
addition, return to Tenant so much of Tenant's security deposit as has not been
applied by Landlord.

            11.8 Waiver. Tenant waives the provisions of any statutes which
relate to termination of leases when leased property is damaged, injured or
destroyed and agrees that such event shall be governed by the terms of this
Lease.

12. UTILITIES. Tenant shall pay for all water, gas, heat, light, power,
electricity, telephone and other utilities and services supplied to the
Premises, together with any taxes thereon. If any such services are not
separately metered to Tenant, Tenant shall pay a reasonable proportion to be
determined by Landlord in its sole discretion of all charges jointly metered
with other premises. Notwithstanding the generality of the foregoing, it is
understood and agreed also that Tenant will be obliged to pay for utilities as
part of its duties.

      In the event that Tenant requests Landlord to construct or cause to be
constructed any extension, expansion or modification of any utility facilities
presently in place or within the Premises, Tenant shall pay all rates and
charges of the utility company for provision of such facilities or services,
including rates, charges and un-refunded security deposits or development fees
which are incurred by reason of the failure to adequately utilize such
facilities or service. In the event that the utility company will enter into a
direct agreement with the Tenant for the nonstandard facilities or service,
Tenant shall do so and shall hold Landlord harmless from any and all costs,
expenses and claims arising out of such agreement. No such agreement which
results in any obligation of the Landlord or to the Premises shall be executed
by Tenant for a term exceeding the term of this Lease without the prior written
consent of Landlord, which shall not be unreasonably withheld.

13. ASSIGNMENT AND SUBLETTING.

            13.1 Landlord's Consent Required. Tenant shall not voluntarily or by
operation of law assign, transfer, mortgage, sublet or otherwise transfer or
encumber all or any part of Tenant's interest in this Lease or in the Premises,
without Landlord's prior written consent, which may not be unreasonably
withheld. Landlord shall issue a response to Tenant's request for consent
hereunder in a timely manner and any attempted assignment, transfer, mortgage,
encumbrance or subletting without such consent shall be void, and shall
constitute a breach of this Lease. Any assignee or sublessee must assume, in
full, the obligations of Tenant under this

                                       10

<PAGE>

Lease and under any other written agreement now or hereafter existing between
Landlord and Tenant.

            13.2 No Release of Tenant. Regardless of Landlord's consent, no
subletting or assignment shall release Tenant of Tenant's obligation or alter
the primary liability of Tenant to pay the rent and to perform all other
obligations to be performed by Tenant hereunder. The acceptance of rent by
Landlord from any other person shall not be deemed to be a waiver by Landlord or
any provision hereof. Consent to one assignment or subletting shall not be
deemed consent to any subsequent assignment or subletting. In the event of
default by any assignee of Tenant or any successor of Tenant, in the performance
of any of the terms hereof, Landlord may proceed directly against Tenant without
the necessity of exhausting remedies against said assignee. Landlord may consent
to subsequent assignments or subletting of this Lease or amendments or
modifications to this Lease with assignees of Tenant, without notifying Tenant,
or any successor of Tenant, and without obtaining its or their consent thereto,
and such action shall not relieve Tenant of liability under this Lease.

            13.3 Attorney's Fees. In the event Tenant shall assign or sublet the
Premise then Tenant shall pay Landlord's reasonable attorneys' fees incurred in
connection therewith.

14. DEFAULTS: REMEDIES.

            14.1 Defaults. The occurrence of any one or more of the following
events shall constitute a material default and breach of this Lease by Tenant:

(a)   the vacating or abandonment of the Premises by Tenant;

(b)   the failure by Tenant to make any payment of rent or any other payment
      required to be made by Tenant hereunder, as and when due, where such
      failure shall continue for period of twenty (20) days following notice;

(c)   the failure by Tenant to observe or perform any of the covenants,
      conditions or provisions of this Lease to be observed or performed by
      Tenant, other than described in paragraph (b) above, where such failure
      shall continue for a period of thirty (30) days after written notice
      thereof from Landlord to Tenant; provided, however, that if the nature of
      Tenant's default is such that more than thirty (30) days are reasonably
      required for its cure, then Tenant shall not be deemed to in default if
      Tenant commences such cure within said thirty (30) day period and
      thereafter diligently prosecutes such cure to completion;

(d)   (i) the making by Tenant of any general arrangement or assignment for the
      benefit of creditors; (ii) Tenant's becoming a "debtor" as defined in 11
      U.S.C. paragraph 101 or any successor statute thereto (unless, in the case
      of a petition filed against Tenant, the same is dismissed within sixty
      (60) days); (iii) the appointment of a trustee or receiver to take
      possession of substantially all of Tenant's assets located at the Premises
      or Tenant's interest in this Lease, where possession is not restored to
      Tenant within thirty (30) days; or (iv) the attachment, execution or other
      judicial seizure of substantially all of Tenant's assets located at the
      Premises, or of Tenant's interest in this Lease, where such seizure is not
      discharged within thirty (30) days; provided, however, in the event that
      any provision of this Paragraph 14.1(d) is contrary to any applicable law,
      such provision shall be enforceable only to the fullest extent permitted
      by law;

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<PAGE>

(e)   Tenant shall do, or permit anything to be done, which creates a lien upon
      the Premises or the Real Property which is not paid, discharged or bonded
      around within ten (10) days after such lien is recorded;

            14.2 Remedies. In the event of any such material default or breach
by Tenant, Landlord may, at any time thereafter, with or without notice or
demand and without waiving or limiting Landlord in the exercise of any right or
remedy which Landlord may have under this Lease, or otherwise at law or in
equity, by reason of such default or breach, exercise any one or more of the
following remedies:

(a)   re-enter the Premises and eject all persons therefrom, using all
      reasonable force necessary to do so, without liability to any person for
      damages sustained by reason of such re-entry. Retain or take possession
      of, and distrain, any property belonging to Tenant upon the premises
      pursuant to Landlord's applicable lien rights. Such Property may be
      removed and stored in a public warehouse or elsewhere at the cost of and
      for the account of Tenant, and Landlord shall in no event be liable for
      any damage or loss thereto; or

(b)   lock the doors to the Premises and exclude Tenant and all other persons
      therefrom (except those authorized by Landlord in its sole and absolute
      discretion); or

(c)   to institute suit against Tenant to collect each installment of rent or
      other sum owned hereunder as it becomes due or to enforce any other
      obligation under this Lease; or

(d)   with or without terminating the Lease, terminate Tenant's right to
      possession of the Premises by any lawful means, in which case Tenant shall
      immediately surrender possession of the Premises to Landlord and Landlord
      shall have the right to re-enter the Premises and remove all persons and
      property therefrom, using all force reasonably necessary for this purpose,
      without being guilty in any manner of trespass or conversion (any claim by
      reason of such re-entry being expressly waived); in such event Landlord
      shall be entitled to recover from Tenant all damages incurred by Landlord
      by reason of Tenant's default including, but not limited to, the cost of
      recovering possession of the Premises, the cost of special tenant
      improvements (beyond standard tenant finish) made for Tenant, expenses of
      reletting, including necessary renovation and alternation of the Premises
      and removal of special tenant improvements made for Tenant, reasonable
      attorney's fees, advertising expense, the costs of protecting and caring
      for the Premises while vacant, the cost of removing and storing Tenant's
      property, any real estate commission actually paid, the worth at the time
      of award by the court having jurisdiction thereof of the amount by which
      the unpaid rent for the balance of the term after the time of such award
      exceeds the amount of such rental loss for the same period that Tenant
      proves could be reasonably avoided; and that portion of any leasing
      commission paid by Landlord pursuant to Paragraph 16 applicable to the
      unexpired term of this Lease. All of the foregoing amounts shall become
      immediately due and payable from Tenant to Landlord upon a default, at
      Landlord's election, which may be exercised with or without the giving of
      notice;

(e)   maintain Tenant's right to possession, in which case this Lease shall
      continue in effect, whether or not Tenant shall have abandoned the
      Premises; in such event, Landlord shall be entitled to enforce all of
      Landlord's rights and remedies under this Lease, including, without
      limitation, the right to recover the rent as it becomes due hereunder and
      any other damages incurred by Landlord from time to time; notwithstanding
      that Landlord shall

                                       12

<PAGE>

      have maintained Tenant's right to possession or shall not have terminated
      the Lease for a default, Landlord may at anytime thereafter, upon notice
      to Tenant, terminate the Lease and/or Tenant's right to possession for
      such prior default;

(f)   pursue any other remedy now or hereafter available to landlord under the
      laws or judicial decisions of the State of Arizona.

      No such re-entry or taking of possession by Landlord shall be construed as
      an election on landlord's part to terminate or surrender this Lease,
      unless a written notice of such intention is then or thereafter served on
      Tenant.

      No failure by Landlord to insist upon the strict performance of any
      covenant, agreement, term or condition of this Lease, or to exercise any
      right or remedy consequent upon a breach thereof, and no acceptance of
      full or partial rent during the continuance of any such breach, shall
      constitute a waiver of any such breach or of such covenant, agreement,
      term or condition. No covenant, agreement, term or condition of this Lease
      to be performed or complied with by Tenant, and no breach thereof, shall
      be waived, altered, modified or terminated except by written instrument
      executed by Landlord. No waiver of any breach shall affect or alter this
      Lease, but each and every covenant, agreement, term and condition of this
      Lease shall continue in full force and effect with respect to any other
      then existing or subsequent breach thereof.

      If Tenant causes or threatens to cause a breach of any of the covenants,
      agreements, terms or conditions contained in this Lease, Landlord shall be
      entitled to obtain and retain all sums held by Tenant, by any trustee or
      in any account provided for herein, to enjoin such breach or threatened
      breach, and to invoke any right and remedy allowed at law or in equity or
      by statute or otherwise as though re-entry, summary proceedings and other
      remedies were not provided for in this Lease.

            14.3 Default by Landlord. Landlord shall not be in default unless
Landlord fails to perform obligations required of Landlord within a reasonable
time, but in no event later than sixty (60) days after written notice by Tenant
to Landlord and to the holder of any first mortgage or deed of trust covering
the Premises whose name and address shall have theretofore been furnished to
Tenant in writing, specifying wherein Landlord has failed to perform such
obligation; provided, however, that if the nature of Landlord's obligation is
such that more than sixty (60) days are required for performance, then Landlord
shall not be in default, if Landlord commences performance within such sixty
(60) day period and thereafter diligently prosecutes the same to completion. In
no event may Tenant terminate this Lease except as and when expressly provided
herein, and Tenant waives any statutes now or hereafter enacted which provide
otherwise.

            14.4 Late Charges. Tenant hereby acknowledges that late payment by
Tenant to Landlord of rent and other sums due hereunder will cause Landlord to
incur costs not contemplated by this Lease, the exact amount of which will be
extremely difficult to ascertain. Such costs include, but are not limited to,
processing and accounting charges and other administrative costs, and late
charges which may be imposed on Landlord by the terms of any mortgage or trust
deed covering the Premises. Accordingly, if any installment of rent or any other
sum due from Tenant shall not be received by Landlord or Landlord's designee
within twenty (20) days after such amount shall be due, then, without any
requirement for notice to Tenant (and notwithstanding any other remedy Landlord
may have hereunder), Tenant shall be obliged to pay

                                       13

<PAGE>

to Landlord, along with the delinquent amount, a late charge equal to six
percent (6%) of such overdue amount. The parties hereby agree that such late
charge represents a fair and reasonable estimate of the cost Landlord will incur
by reason of late payment by Tenant. Acceptance of such late charge by Landlord
shall in no event constitute a waiver of Tenant's default with respect to such
overdue amount, nor prevent Landlord from exercising any of the other rights and
remedies granted hereunder. In the event that a late charge is payable
hereunder, whether or not collected, for three (3) consecutive installments of
rent, then rent shall automatically become due and payable quarterly in advance,
rather than monthly, notwithstanding Paragraph 4 or any other provisions of this
Lease to the contrary. See also Paragraph 19 regarding interest on past-due
obligations.

15. CONDEMNATION. If the premises or any portion thereof are taken under the
power of eminent domain, or sold under the threat of the exercise of said power
(all of which are herein called "condemnation"), this Lease shall terminate as
to the part so taken as of the date the condemning authority takes title or
possession, whichever first occurs (the "Possession Date"). If more than 20% of
the floor area of the Premises is taken by condemnation, Landlord shall have the
right to terminate this Lease as of the Possession Date, by providing tenant
written notice of termination on or before the Possession Date. If more than 20%
of the floor area of the Premises is taken by condemnation, Tenant shall have
the right to terminate this Lease as of the Possession Date by giving Landlord
written notice of such election within ten (10) days after Landlord shall have
given Tenant written notice of such taking (or in the absence of such notice,
within ten (10) days after the condemning authority shall have taken title or
possession, which ever first occurs). In the event of such termination, both
Landlord and Tenant shall be released from further liability under the Lease. If
Landlord or Tenant does not terminate this Lease in accordance with the
foregoing, this Lease shall remain in full force and effect as to the portion of
the Premises remaining, except that the rent shall be reduced in the proportion
that the floor area of the Premises taken bears to the total floor area of the
Premises. If more than twenty-five (25%) of the Floor Area of the building in
which the Premises is located shall be taken by condemnation, or if the nature,
location or extent of any proposed taking or appropriation affecting the Real
Property is such that Landlord elects in good faith to demolish all or
substantially all of the building in which the Premises is located, then
Landlord shall have the right to terminate this Lease upon giving notice of
termination to Tenant at any time after such condemnation. In the event of such
termination, both Landlord and Tenant shall be released from any further
liability under this Lease. Any award for the condemnation of all or any part of
the Premises or the Real Property shall be the property of Landlord, whether
such award shall be made as compensation for diminution in value of the
leasehold or for the taking of the fee, or as severance damages; provided,
however, that Tenant shall be entitled to pursue against the condemning
authority but not against Landlord any award to which Tenant may be entitled
from such condemning authority for loss of or damage to Tenant's trade fixtures
and removable personal property. If this Lease is terminated, an equitable
adjustment shall be made concerning advance rent and any advance payments made
by Tenant to Landlord and Landlord shall, in addition, return to Tenant so much
of Tenant's security deposit as has not been applied by Landlord. In the event
that this Lease is not terminated by reason of such condemnation, Landlord shall
to the extent of severance damages received by Landlord, free of any claim of
the holder of a mortgage or deed of trust on the Premises, in connection with
such condemnation, repair any damage to the Premises caused by such condemnation
except to the extent that Tenant has teen reimbursed therefor by the condemning
authority. Tenant shall pay any amount in excess of such severance damages
required to complete such repair. Tenant hereby waives any statutory rights of
termination which may arise by reason of any partial taking of the Premises by
condemnation.

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<PAGE>

16. ESTOPPEL CERTIFICATE.

            (a) Tenant shall at any time upon not less than ten (10) days' prior
written notice from Landlord execute, acknowledge and deliver to Landlord a
statement in writing (i) certifying that this Lease is unmodified and in full
force and effect (or, if modified, stating the nature of such modifications and
certifying that this Lease, as so modified, is in full force and effect) and the
date to which the rent and other charges are paid in advance, if any; (ii)
acknowledging that there are not, to Tenant's knowledge, any uncured defaults on
the part of Landlord hereunder, or specifying such defaults if any are claimed;
(iii) acknowledging that the Premises are in the condition called for in the
Lease and all improvements have been satisfactorily completed; (iv)
acknowledging that Tenant has unconditionally accepted the Premises, is in
possession thereof, and no defense to the Lease enforcement exists; (v) agreeing
to provide any Landlord mortgagee with opportunity to cure defaults by the
Landlord; and (vi) agreeing not to amend, cancel or assign the Lease in
accordance with Paragraph 13 hereof without the prior written content of any
Landlord mortgagee.

            (b) If Landlord desires to finance, refinance or sell the Premises,
or any part thereof, Tenant hereby agrees to deliver to any lender or purchaser
designated by Landlord such financial statements of Tenant as may be reasonably
required by such lender or purchaser. Such statements shall include the past
three years' financial statements of Tenant. All such financial statements shall
be received by Landlord and such lender or purchaser in confidence and shall be
used only for the purposes herein set forth.

17. LANDLORD'S LIABILITY. The term "Landlord" as used herein shall mean only the
owner or owners at the time in question of the fee title in the Real Property,
and except as expressly provided in Paragraph 16, in the event of any transfer
of such title or interest, Landlord herein named (and in case of any subsequent
transfers then the grantor) shall be relieved from and after the date of such
transfer of all liability as respects Landlord's obligations thereafter to be
performed, provided that any funds in the hands of Landlord or the then grantor
at the time of such transfer, in which Tenant has an interest, shall be
delivered to the grantee. The obligations contained in this Lease to be
performed by Landlord shall, subject as aforesaid, be binding on Landlord's
successors and assigns only during their respective periods of ownership. Tenant
shall attorn to as Landlord succeeding to title in the Real Property, including
any successor to the interest of Landlord named herein.

18. SEVERABILITY. The invalidity of any provision of this Lease as determined by
a court of competent jurisdiction, shall in no way affect the validity of any
other provision hereof.

19. INTEREST ON PAST-DUE OBLIGATIONS. Except as expressly herein provided, any
amount due and payable hereunder to Landlord that is not paid when due shall
bear interest from the date due until paid at the rate of one (1) point over the
prime rate as set by the Wall Street Journal from time to tome. Payment of such
interest shall not excuse or cure any default by Tenant under this Lease.
Interest shall not be payable on late charges incurred by Tenant, nor on any
amounts upon which late charges are paid by Tenant.

20. TIME OF ESSENCE. Time is of the essence of each and every obligation and
duty under this Lease.

                                       15

<PAGE>

21. ADDITIONAL RENT. Any monetary obligations of Tenant to Landlord under the
terms of this Lease shall be deemed to be rent and shall be collectible as such.

22. INCORPORATION OF PRIOR AGREEMENTS: AMENDMENTS. This Lease contains all
agreements of the parties with respect to any matter mentioned herein. No prior
agreement, representation or understanding, whether oral or written, pertaining
to any such matter shall be effective. This lease may be modified in writing
only, signed by the parties in interest at the time of modification. Except as
otherwise stated in this Lease, Tenant hereby acknowledges that neither any real
restate broker involved in any manner with this transaction, nor the Landlord,
nor any employees or agents of any of said persons has made any oral or written
warranties or representations to Tenant relative to the condition or use by
Tenant of said Premises, and Tenant acknowledges that neither any real estate
broker involved in any manner with this transaction, nor the Landlord, nor any
employees or agents of any of said persons has made any oral or written
warranties or representations to Tenant relative to the condition or use by
Tenant of said Premises, and Tenant acknowledges that Tenant assumes all
responsibility regarding the Occupational Safety Health Act, the legal use and
adaptability of the Premises and the compliance thereof with all applicable laws
and regulations in effect during the term of this Lease, except as otherwise
specifically stated in this Lease.

23. NOTICES. Any notice required or permitted to be given hereunder shall be in
writing and may be given by personal delivery or by certified mail; and if given
personally or by mail, shall be deemed sufficiently given if addressed to Tenant
or to Landlord at the address noted below the signature of the respective
parties, as the case may be. Either party may, by notice to the other, specify a
different address for notice purposes, except that upon Tenant's taking
possession of the Premises, the Premises shall constitute Tenant's address for
notice purposes. A copy of all notices required or permitted to be given to
Landlord hereunder shall be concurrently transmitted to such other party or
parties at such addresses as Landlord may from time to time hereafter designate
by notice to Tenant. Any notice shall be deemed received upon hand delivery or
deposit into U.S. Mail. Tenant shall immediately notify Landlord of any of the
following:

(a)   any correspondence or communication from any governmental entity regarding
      the application of Environmental Laws to the Real Property or Tenant's
      operation on the Real Property;

(b))  any change in Tenant's operation on the Real Property that will change or
      has the potential to change Tenant's or Landlord's obligations or
      liabilities under Environmental Laws.

24. WAIVERS. No waiver by Landlord of any provision hereof shall be deemed a
waiver of any other provision hereof or of any subsequent breach by Tenant of
the same of any other provision. Landlord's consent to, or approval of, any act
shall not be deemed to render unnecessary to obtaining of Landlord's consent to
or approval of any subsequent act by Tenant. The acceptance of rent hereunder by
Landlord shall not be a waiver of any preceding breach by Tenant to pay the
particular rent so accepted, regardless of Landlord's knowledge of such
preceding breach at the time of acceptance of such rent.

25. RECORDING. In its discretion, Landlord shall have the right to record this
Lease; otherwise, neither this Lease nor any memorandum of this Lease shall be
publicly recorded or filed.

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<PAGE>

26. HOLDING OVER. If Tenant, with Landlord's consent, remains in possession of
the Premises or any part thereof after the expiration of the term hereof and
without executing a new lease therefor, such occupancy shall be a tenancy from
month to month at a rental in the amount of one hundred fifty percent (150%) of
the rent paid or payable during the last month of the term of this Lease, plus
all other charges payable hereunder and upon all the other provisions of this
Lease pertaining to the obligations of Tenant, but all options and rights of
first refusal, if any, granted under the terms of this Lease shall be deemed
terminated and be of no further effect during said month-to-month tenancy. If
Tenant, without Landlord's express written consent, remains in possession of the
Premises or any part thereof after expiration of the term hereof, Landlord may
re-enter and take possession of the Premises and have all other remedies set
forth in Paragraph 14.2, provided that in addition to such remedies (and not in
lieu thereof), (1) Tenant shall pay for each day of occupancy after expiration
of the term hereof a sum equal to two hundred percent (200%) of the monthly rent
for the last month of the term prorated on a daily basis based upon a thirty day
month; plus (2; any and all consequential and special damages incurred Landlord
as a result of Tenant's holdover without consent including, without limitation,
any consequential and special damages assessed against or paid by Landlord to a
subsequent tenant or prospective tenant.

27. CUMULATIVE REMEDIES. No remedy or election hereunder shall be deemed
exclusive but shall, wherever possible, be cumulative with all other remedies
hereunder or at law or in equity.

28. COVENANTS AND CONDITIONS. Each provision of this Lease performable by Tenant
shall be deemed both a covenant and a condition.

29. BINDING EFFECT: CHOICE OF LAW. Subject to any provisions hereof restricting
assignment or subletting by Tenant and subject to the provisions of Paragraph
18, this Lease shall bind the parties, their personal representatives,
successors and assigns. This Lease shall be governed by the laws of the State of
Arizona.

30. SUBORDINATION.

            (a) This Lease shall not be subordinate to any ground lease,
mortgage, deed of trust, or any other hypothecation of security now or hereafter
placed upon the Real Property of which the Premises are a part, and to any and
all advances made on the security thereof and to all renewals, modifications,
consolidations, replacements and extensions thereof.

            (b) Tenant agrees to execute any documents required to effectuate an
attornment or to make this Lease prior to the lien of any mortgage, deed of
trust or ground lease, as the case may be. Tenant '[s failure to execute such
documents within ten (10) days after written demand shall constitute a material
default by Tenant hereunder, or, at Landlord's option, Landlord shall execute
such documents on behalf of Tenant as Tenant's attorney-in-fact. Tenant does
hereby make, constitute and irrevocably appoint Landlord as Tenant's
attorney-in-fact and in Tenant's name, place and stead, to execute such
documents in accordance with this Paragraph 30(b). See also Paragraph 17
regarding attornment to successors in interest of the Landlord herein named.

31. ATTORNEYS' FEES. If either party brings an action to enforce or construe the
terms hereof or declare rights hereunder, the prevailing party in such action,
on trial or appeal, shall be entitled to have its reasonable attorneys' fees (as
fixed by the court) paid by the other party.

                                       17

<PAGE>

32. LANDLORD'S ACCESS. Landlord and Landlord's agents shall have the right to
enter the Premises at all reasonable times and from time to time for the purpose
of inspecting the same, showing the same to prospective purchasers, lenders, or
lessees, and making such alterations, repairs, improvements or additions to the
Premises or to the building of which they are part as Landlord may deem
necessary or desirable. Landlord may at any time place on or about the Premises
any ordinary "For Sale" signs, and Landlord may at any time during the last one
hundred twenty (120) days of the term hereof place on or about the Premises any
ordinary "For Lease" signs, all without rebate of rent or liability to Tenant.

33. AUCTIONS. Tenant shall not conduct, nor permit to be conducted, either
voluntarily or involuntarily, any auction upon the Premises without first having
obtained Landlord's prior written consent. Notwithstanding anything to the
contrary in this Lease, Landlord shall not be obliged to exercise any standard
of reasonableness in determining whether to grant such consent.

34. SIGNS. Tenant shall not place any signs upon the Premises without Landlord's
prior written consent (which shall not be unreasonably withheld), except that
Tenant shall have the right to place ordinary and usual for sublet signs
thereon. Tenant shall, after receiving Landlord's written consent, erect
appropriate signage in the Tenant's name and conformance with the applicable
sign ordinances and regulations.

35. MERGER. The voluntary or other surrender of this Lease by Tenant, or a
mutual cancellation thereof, or a termination by Landlord, shall not work a
merger and shall, at the option of Landlord, terminate all or any existing
subtenancies or may, at the option of Landlord, operate as an assignment to
Landlord of any or all of such subtenancies.

36. QUIET POSSESSION. Upon Tenant paying the rent for the Premises and observing
and performing all of the covenants, conditions and provisions on Tenant's part
to be observed and performed hereunder, Tenant shall have quiet possession of
the Premises for the entire term hereof, subject to all of the provisions of
this Lease. The individuals executing this Lease as, or on behalf of, Landlord
represent and warrant to Tenant that they are fully authorized and legally
capable of executing this Lease and that such execution is binding upon all
parties holding an ownership interest in the Premises.

37. SECURITY MEASURES. Tenant hereby acknowledges that the rental payable to
Landlord hereunder does not include the cost of guard service or other security
measures, and that Landlord shall have no obligation whatsoever to provide same.
Tenant assumes all responsibility for the protection of Tenant, its agents, its
employees and servants, its invitees and its property from acts of third
parties.

38. EASEMENTS. Landlord reserves to itself the right, from time to time, to
grant such easements, rights and dedications that Landlord deems necessary or
desirable, and to cause the recordation of appropriate plats or restrictions, so
long as such easements, rights, dedications, plats and restrictions do not
unreasonably interfere with the use of the Premises by Tenant. Tenant shall sign
any of the aforementioned documents upon request of Landlord, and failure to do
so shall constitute a material breach of this Lease.

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39. AUTHORITY. Each individual executing this Lease on behalf of Tenant
represents and warrants that he or she is duly authorized to execute and deliver
this Lease on behalf of said Tenant.

40. EXTENSION OF TERM. Subject to the terms of this Paragraph 40, Tenant shall
have the option/right to extend the term of this Lease for four (4) additional
six (6) year terms under the same terms and conditions as set forth in this
Lease, except for those relative to basic rentals payable. During each six (6)
year option period, the monthly fixed rental payable for the option period shall
be an amount equal to he basic monthly rent for the initial three (3) year
period of the lease term adjusted to reflect any increase in the Consumer Price
Index (all items) published by the United States Labor Department for the last
month of the expiring term compared to the first month of the initial six (6)
year term.

In order to exercise the option to extend this Lease:

(1)   Tenant shall give to Landlord notice, in writing, of his intention to do
      so at least one hundred twenty (120) days prior to expiration of the
      original and any option period term of the Lease (and if Tenant shall fail
      to give such notice within the time limit, all rights granted to Tenant to
      renew or extend this Lease shall thereupon be null and void), and

(2)   Tenant shall be in good standing (there shall be no default) under this
      Lease, either at the time such notice is given or at any time thereafter
      until expiration of the original term.

      If Tenant shall exercise the option to extend the term as set forth
herein, then the minimum monthly fixed rental shall be determined as provided
herein.

      In any event, the basic monthly rental payable during each option period
shall be no less than the basic monthly rental payable during the first year of
the original term, increased to reflect the change in the Consumer Price Index
as described in the first Paragraph of this Article 40.

      LANDLORD AND TENANT HAVE CAREFULLY READ AND REVIEWED THIS LEASE AND EACH
TERM AND PROVISION CONTAINED HEREIN AND, BY EXECUTION OF THIS LEASE, SHOW THEIR
INFORMED AND VOLUNTARY CONSENT THERETO. THE PARTIES HEREBY AGREE THAT, AT THE
TIME THIS LEASE IS EXECUTED, THE TERMS OF THIS LEASE ARE COMMERCIALLY REASONABLE
AND EFFECTUATE THE INTENT AND PURPOSE OF LANDLORD AND TENANT WITH RESPECT TO THE
PREMISES.

      The parties hereto have executed this Lease on the dates specified
immediately adjacent to their respective signatures.

LANDLORD:

IMARX INVESTMENTS L.L.C., an Arizona limited liability company

By: /s/ Evan Unger
    ------------------------
Its Principle

Executed on: 11/15/02

Address: 1635 E. 18th Street
         Tucson, AZ 85719

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TENANT:

IMARX THERAPEUTICS, INC., a Delaware corporation

By: /s/ Evan Unger
    ------------------------
Its President and CEO

Executed on: 11-15-02

Address: 1635 E. 18th Street
         Tucson, AZ 85719

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