Exhibit (a)(5)(F)

This announcement is neither an offer to purchase nor a solicitation of an offer to sell Shares (as defined below). The Offer (as defined below) is made solely by the Offer to Purchase, dated September 10, 2010, and the related Letter of Transmittal and any amendments or supplements thereto. Purchaser (as defined below) is not aware of any state where the making of the Offer is prohibited by any administrative or judicial action pursuant to any valid state statute. If Purchaser becomes aware of any valid state statute prohibiting the making of the Offer or the acceptance of the Shares pursuant thereto, Purchaser will make a good faith effort to comply with that state statute or seek to have such statute declared inapplicable to the Offer. If, after a good faith effort, Purchaser cannot comply with the state statute, Purchaser will not make the Offer to, nor will tenders be accepted from or on behalf of, the holders of Shares in that state. Except as set forth above, the Offer is being made to all holders of Shares. In any jurisdiction where the securities, “blue sky” or other laws require the Offer to be made by a licensed broker or dealer, the Offer will be deemed to be made on behalf of Purchaser by one or more registered brokers or dealers that are licensed under the laws of such jurisdiction.

Notice of Offer to Purchase for Cash

All Outstanding Shares of Common Stock

Cogent, Inc.

$10.50 Net Per Share

Ventura Acquisition Corporation

a wholly-owned subsidiary of

3M Company

Ventura Acquisition Corporation, a Delaware corporation (“Purchaser”) and a direct wholly-owned subsidiary of 3M Company, a Delaware corporation (“3M”), is offering to purchase all outstanding shares of common stock, par value $0.001 (the “Shares”), of Cogent, Inc., a Delaware corporation (“Cogent”), at a price of $10.50 per Share, net to the seller in cash (the “Offer Price”), without interest thereon and less any required withholding taxes, upon the terms and subject to the conditions set forth in the Offer to Purchase, dated September 10, 2010, and in the related Letter of Transmittal (which, together with any amendments or supplements thereto, collectively constitute the “Offer”). Tendering stockholders who have Shares registered in their names and who tender directly to Wells Fargo Bank, N.A. (the “Depositary”) will not be obligated to pay brokerage fees or commissions or, except as set forth in the Letter of Transmittal, transfer taxes on the purchase of Shares by Purchaser pursuant to the Offer. Stockholders who hold their Shares through a broker or bank should consult with such institution as to whether it charges any service fees or commissions.

THE OFFER AND WITHDRAWAL RIGHTS WILL EXPIRE AT 12:00 MIDNIGHT, NEW YORK CITY TIME, ON THURSDAY, OCTOBER 7, 2010 UNLESS THE OFFER IS EXTENDED.

The purpose of the Offer is for 3M, through Purchaser, to acquire control of, and the entire equity interest in, Cogent. Following the consummation of the Offer, Purchaser intends to effect the Merger (as defined below).

The Offer is not subject to any financing condition. The Offer is conditioned upon (i) the satisfaction of the Minimum Tender Condition (as described below), (ii) expiration or termination of the applicable waiting period under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended, in the United States and receipt of requisite regulatory approval under the antitrust laws of Austria and (iii) other customary conditions (as described in Section 13 of the Offer to Purchase — “Conditions of the Offer”). The Minimum Tender Condition requires that, prior to the expiration of the Offer, there be validly tendered and not withdrawn that number of Shares which would represent at least a majority of the issued and outstanding Shares on a fully diluted basis. See Section 13 of the Offer to Purchase — “Conditions of the Offer.”

The Offer is being made in connection with the Agreement and Plan of Merger, dated as of August 29, 2010, among Purchaser, Cogent and 3M (the “Merger Agreement”), pursuant to which, after the completion of the Offer and the satisfaction or waiver of certain conditions, Purchaser will be merged with and into Cogent and Cogent will be the surviving corporation (the “Merger”) and each outstanding Share (other than Shares held in the treasury of Cogent or owned by 3M or any direct or indirect wholly-owned subsidiary of 3M or Cogent or held by stockholders who properly demand and perfect appraisal rights under Delaware law) will, by virtue of the Merger and without any action by the holder thereof, be canceled and converted into the right to receive from Purchaser an amount in cash, without interest and subject to applicable withholding taxes, equal to the Offer Price, payable to the holder thereof upon surrender of the certificate formerly representing such Share. The Merger Agreement is more fully described in the Offer to Purchase.

The Cogent board of directors has unanimously approved the Merger Agreement, the Offer and the Merger and determined that the Offer and the Merger are advisable and fair to, and in the best interests of, the holders of Shares. The Cogent board of directors unanimously recommends that the holders of Shares accept the Offer and tender their Shares pursuant to the Offer.

Subject to the provisions of the Merger Agreement and the applicable rules and regulations of the Securities and Exchange Commission (the “Commission”), Purchaser reserves the right (but is not obligated), at any time or from time to time, to waive or otherwise modify or amend the terms and conditions of the Offer in any respect. However, pursuant to the Merger Agreement, Purchaser has agreed that it will not, without the prior written consent of Cogent, waive or modify certain conditions as described in Section 1 of the Offer to Purchase. Subject to the provisions of the Merger Agreement and the applicable rules and regulations of the Commission, Purchaser reserves the right to, and under certain circumstances Cogent may require Purchaser to, extend the Offer, as described in Section 1 of the Offer to Purchase. Pursuant to Rule 14d-11 under the Securities Exchange Act of 1934 and subject to the provisions of the Merger Agreement, Purchaser may elect, or at the request of Cogent be required, to provide a subsequent offering period of no less than ten (10) business days upon expiration of the Offer.

Any extension or amendment of the Offer, waiver of a condition of the Offer, delay in acceptance for payment or payment or termination of the Offer will be followed, as promptly as practicable, by public announcement thereof, such announcement in the case of an extension to be issued not later than 9:00 a.m., New York City time, on the next business day after the previously scheduled Expiration Date (as defined in Section 1 of the Offer to Purchase).

In all cases, payment for Shares tendered and accepted for payment pursuant to the Offer will be made only after timely receipt by the Depositary of (a) certificates representing such Shares or confirmation of the book-entry transfer of such Shares into the Depositary’s account at The Depository Trust Company pursuant to the procedures set forth in Section 3 of the Offer to Purchase, (b) a Letter of Transmittal (or facsimile thereof), properly completed and duly executed, with any required signature guarantees (or, in the case of a book-entry transfer, an Agent’s Message (as defined in Section 3 of the Offer to Purchase) in lieu of the Letter of Transmittal), and (c) any other documents required by the Letter of Transmittal.

For purposes of the Offer, Purchaser will be deemed to have accepted for payment, and thereby purchased, Shares validly tendered and not properly withdrawn if and when Purchaser gives oral or written notice to the Depositary of its acceptance for payment of such Shares pursuant to the Offer. Upon the terms and subject to the conditions of the Offer, payment for Shares accepted for payment pursuant to the Offer will be made by deposit of the purchase price therefor with the Depositary, which will act as agent for the tendering stockholders for the purpose of receiving payments from Purchaser and transmitting such payments to the tendering stockholders. Under no circumstances will interest be paid on the Offer Price, regardless of any extension of the Offer or any delay in payment for Shares.

Except as otherwise provided in Section 4 of the Offer to Purchaser, tenders of Shares pursuant to the Offer are irrevocable. A stockholder may withdraw Shares tendered pursuant to the Offer at any time on or prior to the expiration of the Offer and, unless and until Purchaser has previously accepted them for payment, such Shares may also be withdrawn at any time after November 8, 2010. For a withdrawal of Shares to be effective, a written or facsimile transmission notice of withdrawal must be timely received by the Depositary at one of its addresses set forth on the back cover of the Offer to Purchase. Any notice of withdrawal must specify the name of the person having tendered the Shares to be withdrawn, the number of Shares to be withdrawn and the name of the record holder of the Shares to be withdrawn, if different from that of the person who tendered such Shares. The signature(s) on the notice of withdrawal must be guaranteed by an Eligible Institution (as defined in Section 3 of the Offer to Purchase), unless such Shares have been tendered for the account of any Eligible Institution. If Shares have been tendered pursuant to the procedures for book-entry transfer as set forth in Section 3 of the Offer to Purchase, any notice of withdrawal must specify the name and number of the account at DTC to be credited with the withdrawn Shares. If certificates representing the Shares have been delivered or otherwise identified to the Depositary, the name of the registered owner and the serial numbers shown on such certificates must also be furnished to the

Depositary prior to the physical release of such certificates. All questions as to the form and validity (including time of receipt) of any notice of withdrawal will be determined by Purchaser, in its sole discretion, which determination shall be final and binding. No withdrawal of Shares shall be deemed to have been properly made until all defects and irregularities have been cured or waived. None of 3M, Purchaser or any of their respective affiliates or assigns, the Depositary, the Information Agent (listed below), or any other person will be under any duty to give notification of any defects or irregularities in any notice of withdrawal or incur any liability for failure to give such notification. Withdrawals of tenders of Shares may not be rescinded, and any Shares properly withdrawn will be deemed not to have been validly tendered for purposes of the Offer. However, withdrawn Shares may be retendered by following one of the procedures for tendering Shares described in Section 3 of the Offer to Purchase at any time prior to the expiration of the Offer.

The information required to be disclosed by paragraph (d)(1) of Rule 14d-6 of the General Rules and Regulations under the Securities Exchange Act of 1934 is contained in the Offer to Purchase and is incorporated herein by reference.

The Offer to Purchase and related Letter of Transmittal will be mailed to record holders of Shares whose names appear on Cogent’s stockholder list and will be furnished to brokers, dealers, commercial banks, trust companies and similar persons whose names, or the names of whose nominees, appear on the stockholder list or, if applicable, who are listed as participants in a clearing agency’s security position listing for subsequent transmittal to beneficial owners of Shares.

The exchange of Shares for cash pursuant to the Offer or the Merger will be a taxable transaction for U.S. federal income tax purposes and may also be a taxable transaction under applicable state, local, foreign or other tax laws. Holders of Shares are urged to consult with their own tax advisors as to the particular tax consequences of the Offer and the Merger to them.

The Offer to Purchase and the related Letter of Transmittal and Cogent’s Solicitation/Recommendation Statement on Schedule 14D-9 filed with the Commission in connection with the Offer contain important information and each such document should be read carefully and in its entirety before any decision is made with respect to the Offer.

Questions and requests for assistance may be directed to the Information Agent or the Dealer Manager at their respective addresses and telephone numbers set forth below. Requests for copies of the Offer to Purchase and the related Letter of Transmittal may be directed to the Information Agent or to brokers, dealers, commercial banks or trust companies. Such copies will be furnished promptly at Purchaser’s expense. Purchaser will not pay any fees or commissions to any broker or dealer or any other person (other than the Information Agent) for soliciting tenders of Shares pursuant to the Offer.

The Depositary for the Offer Is:

By Mail:

By Courier (until 6:00 p.m. New York City time

on Thursday, October7, 2010):

Wells Fargo Bank, N.A.

Shareowner Services

Attn: Voluntary Corporate Actions

P.O . Box 64854

St. Paul, MN 55164-0854

Wells Fargo Bank, N.A.

Shareowner Services

Attn: Voluntary Corporate Actions

161 N. Concord Exchange

South St. Paul, MN 55075