Exhibit 10.8
                                                                    ------------



                 FIFTH AMENDMENT TO REVOLVING CREDIT, TERM LOAN
                             AND SECURITY AGREEMENT

     THIS FIFTH AMENDMENT TO REVOLVING CREDIT,  TERM LOAN AND SECURITY AGREEMENT
(the  "Agreement") is entered into as of August 14, 2002 by and among RHEOMETRIC
SCIENTIFIC,  INC.,  a  corporation  organized  under  the  laws of the  State of
Delaware ("RSI"),  RHEOMETRIC  SCIENTIFIC LIMITED, a company organized under the
laws of England and Wales ("RSL"),  RHEOMETRIC SCIENTIFIC FRANCE SARL, a limited
liability  company  organized  under  the  laws of  France  ("RSF"),  RHEOMETRIC
SCIENTIFIC  GmbH, a  corporation  organized  under the laws of Germany  ("RSG"),
RHEOMETRIC SCIENTIFIC F.E. LTD., a corporation organized under the laws of Japan
("RSLFE"),  PROTEIN SOLUTIONS HOLDINGS,  INC., a corporation organized under the
laws of the State of Delaware ("PSI"),  PROTEIN  SOLUTIONS,  INC., a corporation
organized  under the laws of the  Commonwealth  of  Virginia  ("Protein  Inc."),
PROTEIN  SOLUTIONS  LIMITED,  a company  organized under the laws of England and
Wales ("Protein Ltd.") and AVIV INSTRUMENTS, INC., a corporation organized under
the laws of the State of Delaware  ("Aviv")  (collectively  the  "Borrowers" and
individually  each a "Borrower"),  the financial  institutions  which are now or
which  hereafter  become  a  party  hereto  (collectively,   the  "Lenders"  and
individually a "Lender") and PNC BANK,  NATIONAL  ASSOCIATION  ("PNC"), as agent
for Lenders (PNC, in such capacity, the "Agent").

                                    RECITALS

     Whereas,  the Borrowers and PNC entered into a Revolving Credit,  Term Loan
and  Security  Agreement  dated March 6, 2000,  as amended by a First  Amendment
thereto dated August 31, 2000 a Second Amendment thereto dated March 16, 2001, a
Third Amendment thereto dated June 1, 2001, and a Fourth Amendment thereto dated
March 27, 2002 (as may be further amended, the "Loan Agreement"); and

     Whereas,  Borrowers  and PNC have  agreed to  modify  the terms of the Loan
Agreement as set forth in this Agreement.

     Now, therefore, in consideration of PNC's continued extension of credit and
the agreements contained herein, the parties agree as follows:

                                   AGREEMENT

1)   ACKNOWLEDGMENT  OF  BALANCE.  Borrower  acknowledges  that the most  recent
     statement of account sent to Borrower  with respect to the  Obligations  is
     correct.

2)   MODIFICATIONS.  The Loan  Agreement  be and hereby is  modified as follows:


         Section  6.5 of the  Loan  Agreement  be and  hereby  is  deleted,  and
replaced with a new Section 6.5. to read as follows:

              6.5 Fixed Charge Coverage Ratio.  Maintain a Fixed Charge Coverage
         Ratio  of not less  than .20 to 1 for the  three  month  period  ending
         03/31/02; .65 to 1 for the six month period ending 06/30/02,  0.85 to 1
         for the nine  month  period  ending  09/30/02,  1.1 to 1 for the twelve
         month period ending 12/31/02, and maintain,  thereafter, on a quarterly
         basis at each  quarter  end on a rolling  four-quarter  basis,  a Fixed
         Charge Coverage Ratio of not less than 1.10 to 1.

3)   WAIVER.  The Agent and the Lenders hereby waive the  Borrower's  failure to
     comply with Section 6.5,  the Fixed  Charge  Coverage  Ratio for the period
     ending 06/30/02.

4)   ACKNOWLEDGMENTS. Borrowers acknowledge and represent that:

     (A) the Loan Agreement and other Loan Documents,  as amended hereby, are in
     full force and effect without any defense,  claim,  counterclaim,  right or
     claim of set-off;

     (B) to the best of their  knowledge,  no default by the Agent or Lenders in
     the  performance of their duties under the Loan Agreement or the other Loan
     Documents has occurred;


<PAGE>


     (C) all  representations  and warranties of the Borrowers  contained herein
     and in the  other  Loan  Documents  are true and  correct  in all  material
     respects as of this date,  except for any  representation  or warranty that
     specifically refers to an earlier date;

     (D) Borrowers  have taken all  necessary  action to authorize the execution
     and delivery of this Agreement; and

     (E) this Agreement is a modification of an existing obligation and is not a
     novation.

5)   PRECONDITIONS.  As a  precondition  to  the  effectiveness  of  any  of the
     modifications,  consents,  or waivers contained herein, the Borrower agrees
     to:

     (A) provide the Bank with a resolution, in form and substance acceptable to
     the Bank, which approves the modification contemplated hereby.

     (B) pay to the Bank a waiver fee in the amount of $50,000.

     (C) pay all other fees and costs incurred by the Bank in entering into this
     Agreement.

6)   MISCELLANEOUS.  This  Agreement  shall be construed in accordance  with and
     governed by the laws of the State of New Jersey,  without reference to that
     state's  conflicts of law  principles.  This  Agreement  and the other Loan
     Documents  constitute the sole agreement of the parties with respect to the
     subject  matter  thereof  and  supersede  all oral  negotiations  and prior
     writings with respect to the subject matter  thereof.  No amendment of this
     Agreement,  and no waiver of any one or more of the provisions hereof shall
     be effective  unless set forth in writing and signed by the parties hereto.
     The illegality,  unenforceability or inconsistency of any provision of this
     Agreement   shall  not  in  any  way   affect  or  impair   the   legality,
     enforceability or consistency of the remaining provisions of this Agreement
     or the other Loan  Documents.  This  Agreement and the other Loan Documents
     are intended to be consistent. However, in the event of any inconsistencies
     among  this  Agreement  and any of the Loan  Documents,  the  terms of this
     Agreement,  then the Loan Agreement,  shall control.  This Agreement may be
     executed  in any number of  counterparts  and by the  different  parties on
     separate  counterparts.  Each such counterpart shall be deemed an original,
     but all  such  counterparts  shall  together  constitute  one and the  same
     agreement.

7)   DEFINITIONS.  The terms used herein and not  otherwise  defined or modified
     herein shall have the meanings ascribed to them in the Loan Agreement.  The
     terms used herein and not otherwise  defined or modified  herein or defined
     in the Loan  Agreement  shall  have the  meanings  ascribed  to them by the
     Uniform Commercial Code as enacted in New Jersey.


IN WITNESS  WHEREOF,  the undersigned  have signed and sealed this Agreement the
day and year first above written.



ATTEST:                                 RHEOMETRIC SCIENTIFIC, INC.





BY: /s/ Joseph Musanti                  By: /s/ Mark F. Callaghan
   ---------------------                   -------------------------------------
   Name: JOSEPH MUSANTI                    Name: MARK F. CALLAGHAN
   Title:  Asst.  Secretary                Title:  Executive Vice President


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<PAGE>



                                        RHEOMETRIC SCIENTIFIC LIMITED


                                        By:  /s/ Joseph Musanti
                                           -------------------------------------
                                           Name:  JOSEPH MUSANTI
                                           Title: Director



                                        RHEOMETRIC SCIENTIFIC FRANCE SARL


                                        By:  /s/ Joseph Musanti
                                           -------------------------------------
                                           Name:  JOSEPH MUSANTI
                                           Title: mANAGER



                                        RHEOMETRIC SCIENTIFIC GmbH


                                        By:  /s/ Joseph Musanti
                                           -------------------------------------
                                           Name:  JOSEPH MUSANTI
                                           Title: Under Power of Attorney from
                                           Manfred Herzog, Managing Director



                                        RHEOMETRIC SCIENTIFIC F.E. LTD.


                                        By:  /s/ Joseph Musanti
                                           -------------------------------------
                                           Name:  JOSEPH MUSANTI
                                           Title: Chairman and Representative
                                           Director



ATTEST:                                 PROTEIN SOLUTIONS HOLDINGS, INC.



BY: /s/ Joseph Musanti                  By: /s/ Mark F. Callaghan
   ---------------------                   -------------------------------------
   Name: JOSEPH MUSANTI                    Name: MARK F. CALLAGHAN
   Title:  Asst.  Secretary                Title:  Vice President



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<PAGE>



ATTEST:                                 PROTEIN SOLUTIONS, INC.



BY: /s/ Joseph Musanti                  By: /s/ Mark F. Callaghan
   ---------------------                   -------------------------------------
   Name: JOSEPH MUSANTI                    Name: MARK F. CALLAGHAN
   Title:  Asst.  Secretary                Title:  Vice President


                                        PROTEIN SOLUTIONS LIMITED



                                        By:  /s/ Mark F. Callaghan
                                           -------------------------------------
                                           Name: MARK F. CALLAGHAN
                                           Title: Director



ATTEST:                                 AVIV INSTRUMENTS, INC.



BY: /s/ Joseph Musanti                  By: /s/ Mark F. Callaghan
   ---------------------                   -------------------------------------
   Name: JOSEPH MUSANTI                    Name: MARK F. CALLAGHAN
   Title:  Asst.  Secretary                Title:  Vice President



                                        PNC BANK, NATIONAL ASSOCIATION
                                        Lender and as Agent


                                        By:  /s/ Arthur V. Lippens
                                           -------------------------------------
                                           Name: ARTHUR V. LIPPENS
                                           Title: Director





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