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                                                                 EXHIBIT 10(b)

                              CONSULTING AGREEMENT

         THIS CONSULTING AGREEMENT made as of this 1st day of July, 2000 (the
"Agreement") by and between Alliance Pharmaceutical GmbH, a German corporation
(the "Company") and Jean Riess, whose address is Les Giaines, 06950 Falicon,
France, ("Consultant").

                              W I T N E S S E T H:

         WHEREAS, the Company desires to retain Consultant as an independent
contractor to provide international consulting services in the area of
pharmaceutical drug development and regulatory filing, especially in flurocarbon
derived pharmaceuticals and other services as requested from time to time
(collectively, the "Consulting Services"), and Consultant desires to serve in
such capacity, during the period and upon the terms and conditions hereinafter
set forth;

         NOW, THEREFORE, in consideration of the foregoing and the mutual
promises herein contained, the parties hereto agree as follows:

         1.       TERM. The term of this Agreement shall commence on the date
hereof and continue until June 30, 2001, and can be extended by the mutual
agreement of the parties.

         2.       CONSULTING SERVICES. During the term of this Agreement,
Consultant shall devote adequate time and attention to performance of the
Consulting Services as reasonably necessary, or as requested by the Company. The
Consulting Services shall be conducted in accordance with all applicable laws,
rules and regulations and industry standards.

         3.       COMPENSATION. The Company shall pay the Consultant such
amounts as the parties will agree for Consulting Services rendered. Such fee
shall accrue and be payable promptly upon presentation of periodic invoices. All
reasonable out-of-pocket expenses incurred by Consultant in connection with the
Consulting Services hereunder shall be reimbursed by the Company.

         4.       TERMINATION. Either party shall have the right to terminate
this Agreement at any time upon ten (10) days written notice to the other party.
All obligations in Sections 5 and 6 herein shall survive any termination or
expiration of this Agreement. Consultant agrees to return all Confidential
Information and copies thereof upon termination. Notwithstanding anything to the
contrary contained herein, the obligations of the Company to pay the
compensation in Section 3 shall be terminated automatically upon the first to
occur of any of the following events:

                  (a)      Consultant shall willfully breach any of the
provisions of this Agreement.

                  (b)      Consultant shall commit any fraud, embezzlement or
other act of dishonesty against the Company.

         5.       CONFIDENTIALITY. Consultant recognizes that the Company and
its subsidiaries and affiliated corporations (herein collectively referred to as
the "Company") and its customers, corporate partners or others (herein
collectively referred to as "Related Parties"), own certain confidential
information, including but not limited to, secret or confidential data,
proprietary information, trade secrets, technology, formulae, processes,
procedures, scientific studies,

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regulatory submissions, business plans, information and the like, whether all of
the same be in writing or not (all of which is referred to as "Confidential
Information"). Consultant acknowledges that the Company has disclosed or may
disclose to Consultant portions of Confidential Information of the Company or
Related Parties, and agrees to maintain the confidential status of such
Confidential Information. Consultant further agrees not to use such Confidential
Information except in pursuit of Consultant's duties hereunder or to disclose
the same to persons not authorized in writing by the Company to receive such
Confidential Information. Consultant will not make and will take all reasonable
steps necessary to prevent unauthorized parties from making any copies,
abstracts or summaries of any of the Confidential Information except in pursuit
of Consultant's duties hereunder and for the sole use and account of the
Company.

         6.       INVENTIONS. Consultant will disclose promptly and in writing
to the Company, all ideas, concepts, formulae, processes, procedures,
inventions, software, devices or improvements, whether or not patentable or
copyrightable, related in any manner to the work or other activities carried on
by the Company ("Inventions") which Consultant, alone or with others, may
conceive or reduce to practice during the term of Consultant's provision of
Consulting Services to the Company. Consultant agrees to assign, transfer,
convey and deliver to the Company, and hereby does assign, transfer and convey
to the Company, all right, title and interest in and to all Inventions required
to be disclosed by Consultant to the Company under this Agreement and all
patents and patent applications (including continuations, continuations-in-part,
divisions, reissues, renewals and extensions) and all copyrights and copyright
applications for all countries relating to such Inventions. Consultant will,
during the term of this Agreement and at any time thereafter, execute all papers
and perform all acts and cooperate with the Company and its counsel in any other
way which, in the sole view of the Company, is necessary and proper to make this
provision effective. All reasonable expenses in connection with the obligations
of Consultant under this Section 6 shall be borne by the Company or its nominee.

         7.       RELATIONSHIP. The relationship between the Company and
Consultant in the performance of Consulting Services under this Agreement shall
be that of independent contractors, and nothing herein shall be construed to
create a relationship of principal and agent, employer and employee, joint
venturers, co-partners or any other similar relationship between the Company and
Consultant. Neither party hereto shall be liable in any way for any engagement,
obligation, liability, contract, representation or warranty of the other party
to or with any third party or purchasers whomsoever.

         8.       ASSIGNABILITY AND BINDING EFFECT. The obligations of
Consultant may not be delegated, and Consultant may not assign, transfer,
pledge, encumber, hypothecate or otherwise dispose of this Agreement, or any
rights hereunder, and any attempted delegation or disposition shall be null and
void and without effect.

         9.       GENERIC DRUG ENFORCEMENT ACT OF 1992. Consultant represents
that it has never been (i) debarred or (ii) convicted of a crime for which a
person can be debarred, under Section 306(a) or 306(b) of the Generic Drug
Enforcement Action of 1992. Consultant represents that it has never been and, to
the best of its knowledge after due inquiry, has ever been (a) threatened to be
debarred or (b) indicted for a crime or otherwise engaged in conduct for

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which a person can be debarred, under Section 306(a) or (b). Consultant agrees
that it will promptly notify each Client in the event of any such debarment,
conviction, threat or indictment.

         10.      HEADINGS. The headings set forth in this Agreement are for
convenience only and shall not be considered as part of this Agreement in any
respect nor shall they in any way affect the substance of the provisions
contained in this Agreement.

         11.      SEVERABILITY. The invalidity of all or any part of any
provision of this Agreement shall not invalidate the remainder of this Agreement
or the remainder of any section which can be given effect without such invalid
provision.

         12.      ENTIRE AGREEMENT. This Agreement constitutes the sole and
entire agreement between Consultant and the Company with respect to the
acceptance by the Company of the consulting and advisory services of Consultant
and supersedes all prior agreements, arrangements and understandings. This
Agreement may not be altered, modified or amended except by written instrument
signed by the party against whom such alteration, modification or amendment is
sought to be enforced.

         13.      GOVERNING LAW. This Agreement shall be governed by and
construed and interpreted in accordance with the laws of Germany. Consultant
acknowledges that improper disclosure of Confidential Information or breach of
other obligations herein could cause irreparable harm to the Company, and agrees
that the Company may seek injunctive relief to enforce the terms of this
Agreement.

         IN WITNESS WHEREOF, the parties have executed this Agreement on the day
and year first above written.

ALLIANCE PHARMACEUTICAL GMBH           CONSULTANT

By:                                    By:
    --------------------------             --------------------------
    H. Joerg Limmer                        Jean Riess

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                                                               Exhibit 10(c)(ix)

                              EMPLOYMENT AGREEMENT

This Agreement is made as of August , 2000 by and between American Science and
Engineering, Inc. (the "Company"), a Massachusetts corporation having its
principal place of business in Billerica, Massachusetts, and Richard Mastronardi
(the "Executive").

The Company desires to continue to receive the services of the Executive, and
the Executive is willing to continue to render such services, in accordance with
the terms hereinafter set forth.

Accordingly, the Company and the Executive agree as follows:

1. The Company agrees to continue to employ the Executive as, and the Executive
agrees to continue to perform the duties of Vice President, Field Operations of
the Company.

2. (a) The Company shall pay to the Executive the "Severance Payment" in the
event that the Executive is terminated by the Company within sixty (60) days
prior to or twelve (12) months after the occurrence of a "Change of Control," as
defined below. The Severance Payment shall be made at the time of such
termination.

   (b) The "Severance Payment" shall be a one-time payment equal to the
higher of: (i) the Executive's base salary for one year at the annual rate in
effect one month prior to the occurrence of the Change of Control, or (ii) the
Executive's base salary for one year at the annual rate in effect at the time of
such termination. The Severance Payment shall also include the continuation of
all benefits received by the Executive prior to termination for a period equal
to the lesser of one year or the start of new employment by the Executive in
which he receives substantially similar benefits.

      (c) A "Change of Control" shall be deemed to have occurred if:

      (i) any person (as defined in Section 13(d) or 14(d)(2) of the Securities
      Exchange Act of 1934) shall have become the beneficial owner of 50 percent
      or more of the combined voting power of the Company's voting securities;

      (ii) the Continuing Directors shall have ceased for any reason to
      constitute a majority of the Board of Directors of the Company. For this
      purpose, a "Continuing Director" shall include members of the Board of
      Directors of the Company as of the date of this Agreement and any person
      nominated for election to the Board of Directors of the Company by a vote
      of the majority of the then Continuing Directors;

      (iii) the stockholders approve the complete liquidation or dissolution of
      the Company, or

      (iv) the stockholders approve by the requisite vote any of the following
      transactions: (A) a merger or consolidation of the Company (except for a
      merger in respect of which no vote of the stockholders of the Company is
      required); (B) a sale, lease, exchange,

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      mortgage, pledge, transfer or other disposition (in one transaction or a
      series of transactions), whether as part of a dissolution or otherwise, of
      assets of the Company or of any direct or indirect majority-owned
      subsidiary or the Company (other than to any direct or indirect
      wholly-owned subsidiary or to the Company) having an aggregate market
      value equal to 50% or more of either the aggregate market value of all of
      the assets of the Company determined on a consolidated basis or the
      aggregate market value of all the outstanding stock of the Company
      immediately prior to the transaction; or (C) a tender or exchange offer
      for 50% or more of the outstanding voting stock of the Company.

3. (a) If the Executive is terminated for any reason other than (i) Cause (as
defined below), or (ii) a Change of Control (as defined in Paragraph 2) (such
other reasons referred to hereinafter as "Termination for Convenience") the
Executive shall receive an amount equal to the greater of the amount that would
be due under the Company's then-current severance policy, if any, or six months
of his then-current base salary, payable, at the Company's option, on the last
date of his employment or in weekly installments. In case of Termination for
Convenience, the Executive shall be entitled to a continuation of all benefits
being received by him at the time of termination for the lesser of six (6)
months from the date of termination, or until the date in which the Executive
begins new employment in which he receives substantially similar benefits. If
the Executive is Terminated for Convenience within twelve (12) months of a
change in the Company's President/CEO, the Executive shall be entitled to
receive the Severance Payment described in Paragraph 2(b) in place of the
benefits described in this Paragraph 3.

   (b) For the purposes of this Agreement, "Cause" shall mean: (i) the
determination by the President of the Company, in agreement with the Board of
Directors, that the Executive has willfully failed to perform his duties in the
course of his employment under this Agreement consistent with those of a Vice
President, Field Operations as expressly instructed by the President/CEO; or
(ii) the final conviction of the Executive for, or his plea of nolo contendere
to, a felony or any other crime which involves fraud, dishonesty or moral
turpitude.

4. The Company may not assign all or any part of its obligations under this
Agreement, except to a successor as provided for in this paragraph. The Company
will require any successor (whether direct or indirect, by purchase, merger,
consolidation or otherwise) to all or substantially all of the business or
assets of the Company expressly to assume and agree to perform this Agreement to
the same extent that the Company would be required to perform it if no
succession had taken place. As used in this Agreement, unless the context
requires otherwise, the "Company" shall mean the Company as defined above or any
successor to its business or assets as aforesaid which assumes and agrees to
perform this Agreement, by operation of law, or otherwise. This Agreement shall
inure to the benefit of and be enforceable by and binding upon (i) any such
successor and (ii) the Executive's personal or legal representatives, executors,
administrators and designated beneficiaries.

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5. This Agreement contains the entire agreement between the parties with respect
to the subject matter hereof and supersedes all prior oral and written
agreements, understandings and commitments between the parties relating to this
Agreement. Notwithstanding the foregoing, the Executive shall at all times
remain subject to all policies and procedures of the Company that relate to
employees of the Company, except to the extent that this Agreement contains
terms or provisions that are contrary to or provides greater benefits than such
policies and procedures, in which case this Agreement shall control. No
amendment to this Agreement shall be made except by a written instrument signed
by both parties.

6. This Agreement shall be construed and enforced under and be governed in all
respects by the law of The Commonwealth of Massachusetts, without regard to the
conflict of law principles thereof.

IN WITNESS WHEREOF, the Company has caused this instrument to be executed on its
behalf by a duly authorized officer and the Executive has executed this
instrument, all as of the date set forth above.

                                      AMERICAN SCIENCE AND ENGINEERING, INC.

                                      By: /s/ Ralph S. Sheridan, President
                                          --------------------------------
                                          Ralph S. Sheridan, President

                                          /s/ Richard Mastronardi
                                          --------------------------------
                                          Richard Mastronardi

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