254 F.3d 1031 (Fed. Cir. 2001)
APOTEX USA, INC.,   Plaintiff-Appellant,v.MERCK & CO., INC., Defendant-Appellee.
00-1272
United States Court of Appeals for the Federal Circuit
DECIDED: June 8, 2001Corrected: June 26, 2001

Appealed from: U.S. District Court for the Northern District of Illinois  Judge Matthew F. Kennelly [Copyrighted Material Omitted]
Alan H. Bernstein, Caesar, Rivise, Bernstein, Cohen & Pokotilow, LTD., of Philadelphia, Pennsylvania, argued for plaintiff-appellant. With him on the brief were Robert S. Silver and William Joseph Castillo.
Nicolas G. Barzoukas, Howrey Simon Arnold & White, LLP, of Houston, Texas, argued for defendant-appellee. With him on the brief were John F. Lynch, Gerard M. Devlin, Jr., and Peter J. Chassman, Howrey Simon Arnold & White, LLP, and Paul D. Matukaitis, Merck & Company, of White Station, New Jersey.
Before LOURIE, CLEVENGER, and LINN, Circuit Judges.
LOURIE, Circuit Judge.


1
Apotex USA, Inc. appeals from the decision of the United States District  Court for the Northern District of Illinois granting Merck & Co., Inc.'s  motion for summary judgment that the claims of U.S. Patents 5,573,780 and  5,690,962 are invalid under 35 U.S.C. § 102(g). Apotex Corp. v. Merck &  Co., No. 96-C-7375, (N.D. Ill. Jan. 25, 2000) ("Apotex  I"). Because the district court did not err in granting summary judgment  that the '780 and '962 patents are invalid under 35 U.S.C. § 102(g), we  affirm.

BACKGROUND

2
Apotex is the assignee of the '780 and '962 patents, which relate to a  process for making a stable solid formulation of enalapril sodium for use  in the treatment of high blood pressure. Apotex I at *1. Claim 1 of the  '780 patent, which is representative of the claims at issue, reads as  follows:


3
1. A process of manufacture of a pharmaceutical solid composition comprising enalapril sodium, which process comprises the steps of:


4
i) a) mixing enalapril maleate with an alkaline sodium compound and at least one other excipient, adding water sufficient to moisten, and mixing to achieve a wet mass, or


5
b) mixing enalapril maleate with at least one excipient other than an alkaline sodium compound, adding a solution of an alkaline sodium compound in water, sufficient to moisten and mixing to achieve a wet mass; thereby to achieve a reaction without converting the enalapril maleate to a clear solution of enalapril sodium and maleic acid sodium salt in water,


6
ii) drying the wet mass, and iii) further processing the dried material into tablets.


7
'780 patent, col. 5, l. 34 to col. 6, l. 15. The claims of the '962  patent, which is a continuation of the application that led to the '780  patent, are identical to those found in the '780 patent except that they  are not restricted to tablet form, but rather encompass any solid  pharmaceutical dosage form of enalapril sodium. '962 patent, col. 5, l.  22 to col. 6, l. 11. This distinction is not material to the resolution  of this appeal.


8
Merck manufactures enalapril sodium under the trade name VASOTEC , and  has been continuously manufacturing and commercially selling VASOTEC   tablets since 1983. Apotex I at *7. Merck owns both U.S. and Canadian  patents covering the enalapril sodium compound, but does not own a patent  covering its process of manufacturing VASOTEC . Id. at *1. However, in  1992, Merck disclosed the ingredients utilized in its VASOTEC   manufacturing process in a Canadian product monograph, and more than  30,000 copies of the monograph were distributed in 1993 alone. Id. at *7.  Merck also disclosed the ingredients used in manufacturing RENITEC  (the  trademark used for its enalapril sodium product sold in various foreign  countries) in the 1988 edition of the Dictionnaire Vidal, a French  pharmaceutical dictionary. Id.


9
In 1991, Merck and its Canadian subsidiary, Merck Frosst Canada, Inc.,  sued Apotex's Canadian affiliate, Apotex Canada, for infringement of  Merck's Canadian patent covering the enalapril sodium compound. Id. at  *1. During the 1994 trial ("the Canadian trial"), Brian McLeod, Merck's  then-vice president of marketing, performed a step-by-step narration of a  videotape demonstrating Merck's process of manufacturing VASOTEC . Id.  Within days of hearing this testimony, Dr. Bernard Sherman, an Apotex  official, allegedly conceived the patented process at issue. Id.


10
Apotex filed the present action against Merck, alleging that Merck's  process of manufacturing VASOTEC  infringes all of the claims of both the  '780 and '962 patents. Id. Both parties filed cross-motions for summary  judgment on the issue of infringement, and Merck cross-moved for summary  judgment of invalidity under § 102(g). Id. The district court granted  Apotex's motion for summary judgment of infringement, but also granted  Merck's cross-motion for summary judgment of invalidity because it found  that Merck invented the process claimed in the '780 and '962 patents  within the United States before Apotex, and did not abandon, suppress, or  conceal that invention within the meaning of § 102(g). Id. at *9.


11
Apotex thereafter filed a motion asking the court to reconsider its grant  of summary judgment of invalidity, which the district court denied.  Apotex Corp. v. Merck & Co., No. 96-C-7375, (N.D. Ill.  Mar. 17, 2000). Apotex appeals from the district court's grant of summary  judgment of invalidity. We have jurisdiction pursuant to 28 U.S.C.  § 1295(a)(1) (1994).

DISCUSSION

12
Summary judgment is appropriate "if the pleadings, depositions, answers  to interrogatories, and admissions on file, together with the affidavits,  if any, show that there is no genuine issue as to any material fact and  that the moving party is entitled to a judgment as a matter of law."  Fed. R. Civ. P. 56(c). For purposes of the motion, "[t]he evidence of the  nonmovant is to be believed, and all justifiable inferences are to be  drawn in his favor." Anderson v. Liberty Lobby, Inc., 477 U.S. 242, 255  (1986). We review a district court's grant of a motion for summary  judgment de novo. Ethicon Endo-Surgery, Inc. v. United States Surgical  Corp., 149 F.3d 1309, 1315, 47 USPQ2d 1272, 1275 (Fed. Cir. 1998).


13
Apotex argues that the district court improperly invalidated the '780 and  '962 patents because Merck failed to prove by clear and convincing  evidence that it did not suppress or conceal the patented process.  Apotex contends that proof of invalidity under § 102(g) requires Merck to  prove that it did not suppress or conceal the process of manufacturing  VASOTEC  tablets based on its activities within the United States, and  that Merck's foreign disclosures therefore cannot be used to satisfy its  burden of proof. Apotex also contends that, in any event, Merck's foreign  disclosures fail to prove that it did not suppress or conceal the process  because nothing in the testimony from the Canadian trial, the product  monograph, or the French dictionary disclosed the use of water, the  occurrence of an acid-base chemical reaction between enalapril maleate  and sodium bicarbonate, or the resultant enalapril sodium product.  Finally, Apotex argues that the evidence demonstrates that Merck in fact  suppressed or concealed its invention by failing to file a patent  application on the process, by submitting misleading information in its  New Drug Application ("NDA") that only disclosed the starting ingredients  used to make VASOTEC , and by preventing the details of its process from  circulating outside of the company.


14
Merck responds that § 102(g) only requires proof that the prior invention  was made in the United States, and that evidence of lack of suppression  or concealment can be proven by both foreign and domestic activities.  Merck further argues that it did not suppress or conceal the process  because it used it commercially, disclosed it in open court directly to  its competitor, and published the ingredients used to make VASOTEC   tablets in both the product monograph and the French dictionary. Merck  also argues that the submissions it made with respect to its NDA were  proper and in any event could not constitute suppression or concealment  because it was the Food and Drug Administration that never made those  submissions public. Finally, Merck contends that the process was not  suppressed or concealed because it was obvious and Dr. Sherman admitted  that VASOTEC  tablets could be reverse-engineered to reveal the details  of the process.


15
Section 102(g) operates to ensure that a patent is awarded only to the  "first" inventor in law. In addition to governing priority determinations  in interference proceedings in the United States Patent and Trademark  Office, § 102(g) may be asserted as a basis for invalidating a patent in  defense to an infringement suit. New Idea Farm Equip. Corp. v. Sperry  Corp., 916 F.2d 1561, 1566, 16 USPQ2d 1424, 1428 (Fed. Cir. 1990)  (citation omitted). That section provides in relevant part that: "A  person shall be entitled to a patent unless . . . before such person's  invention thereof, the invention was made in this country by another  inventor who had not abandoned, suppressed, or concealed it." 35 U.S.C.A.  § 102(g) (West Supp. 2000). Therefore, if a patentee's invention has been  made by another, prior inventor who has not abandoned, suppressed, or  concealed the invention, § 102(g) will invalidate that patent. New Idea,  916 F.2d at 1566, 16 USPQ2d at 1428.


16
Apotex does not dispute that Merck invented the patented process in the  United States well before Dr. Sherman's alleged date of conception.  Apotex also concedes that Merck did not abandon its process of  manufacturing VASOTEC  tablets as shown by its continuous commercial use  of the process since 1983. The sole issue on appeal, therefore, is  whether Merck "suppressed" or "concealed" the process within the meaning  of § 102(g). Whether suppression or concealment has occurred is a  question of law, which we review de novo. Brokaw v. Vogel, 429 F.2d 476,  480, 166 USPQ 428, 431 (CCPA 1970).


17
As an initial matter, we disagree with Apotex's interpretation of  § 102(g) as requiring proof negating suppression or concealment to arise  from activities occurring within the United States. The plain language of  § 102(g) clearly requires that the prior invention be made "in this  country." However, in light of the grammatical structure of § 102(g), it  would be a strained reading of that provision to interpret the language  "in this country" to also modify the requirement that the prior invention  was "not . . . abandoned, suppressed, or concealed." A more reasonable  interpretation is that it only modifies the antecedent verb "made," but  not the "abandoned, suppressed, or concealed" clause that follows it.  Had Congress intended the phrase "in this country" to modify "abandoned,  suppressed, or concealed," it would have inserted language to that  effect.


18
Indeed, if there were any doubt, the legislative history of § 102(g)  demonstrates that Congress contemplated that precise modification, as it  applied to another clause in § 102(g), and failed to adopt it. An earlier  version of that provision considered in the House read as follows:


19
[B]efore the applicant's invention thereof the invention was in fact made in this country by another who had not abandoned it and who was using reasonable diligence in this country in reducing it to practice or had reduced it to practice.


20
H.R. 3760, 82nd Cong. (1951) (emphasis added). The fact that the drafters  found it desirable to emphasize that the language "in this country"  applies to "using reasonable diligence" as well as to the word "made"  supports the conclusion that it only modifies the verb that precedes it  and not any subordinate clause that follows it. Accordingly, based upon  the plain language of § 102(g) and the relevant legislative history of  that provision, we conclude that the language "in this country" only  applies to the country where "the invention was made," and that proof  negating suppression or concealment is not limited to activities  occurring within the United States.


21
We next turn to an issue that has not been squarely addressed by this  court in considering suppression or concealment as negating prior  invention in a defense to an infringement suit under § 102(g) - the  burdens of proof governing such a determination. Section 282 of the  Patent Act provides that "[a] patent shall be presumed valid." 35  U.S.C.A. § 282 (West Supp. 2000). In order to overcome the presumption of  validity, the party challenging a patent must prove facts supporting a  determination of invalidity by clear and convincing evidence. Am. Hoist &  Derrick Co. v. Sowa & Sons, Inc., 725 F.2d 1350, 1360, 220 USPQ 763, 770  (Fed. Cir. 1984). Section 282 applies with full force to a § 102(g)  defense, and thus a party asserting invalidity under § 102(g) must prove  facts by clear and convincing evidence establishing a prior invention  that was not abandoned, suppressed, or concealed. See Kimberly-Clark  Corp. v. Procter & Gamble Distrib. Co., 973 F.2d 911, 915, 23 USPQ2d  1921, 1924 (Fed. Cir. 1992).


22
In Young v. Dworkin, one of our predecessor courts set forth the relevant  burdens of proof governing a determination whether a prior invention was  suppressed or concealed, in the context of an interference between co-  pending applications, as follows:


23
The sole remaining question is whether the board correctly held that junior party-appellant suppressed or concealed his invention within the meaning of 35 U.S.C. § 102(g). Here, the senior party-appellee bears the burden of proof by a preponderance of the evidence, notwithstanding junior party-appellant's burden on the issue of priority of invention which he has sustained.


24
Young v. Dworkin, 489 F.2d 1277, 1279, 180 USPQ 388, 390 (CCPA 1974)  (citing Gallagher v. Smith, 206 F.2d 939, 99 USPQ 132 (CCPA 1953)).  Thus, under § 102(g) interference law involving co-pending applications,  once the first party to invent has established priority of invention, the  second party to conceive and reduce the invention to practice has the  burden of proving that the first party suppressed or concealed the  invention. In such an interference, the first party to invent does not  bear any burden of proof regarding suppression or concealment once it has  established an earlier date of invention.


25
A § 102(g) prior invention defense is governed by the identical  "suppressed or concealed" language applicable to priority determinations  in interference proceedings. 35 U.S.C. § 102(g). We must therefore  interpret the § 102(g) defense provision consistently with established  interference law. However, infringement actions implicating a § 102(g)  defense differ from interferences in that a patent has been granted on  the invention at issue, and therefore the presumption of validity under  § 282 applies.1 Because the patentee (analogous to the second-  to-invent in the interference context) has the benefit of the presumption  of validity, that party should only be held to bear a burden of producing  evidence indicating that the prior inventor may have suppressed or  concealed the invention once the challenger (analogous to the first-to-  invent in the interference context) has established prior invention by  clear and convincing evidence. That burden bears a rough similarity to  placing the burden of proving suppression or concealment on the second-  to-invent under interference law, but at the same time is appropriately  limited to one of production, not persuasion, giving due regard to the  presumption of validity.


26
We therefore interpret § 102(g) as requiring that once a challenger of a  patent has proven by clear and convincing evidence that "the invention  was made in this country by another inventor," 35 U.S.C. § 102(g), the  burden of production shifts to the patentee to produce evidence  sufficient to create a genuine issue of material fact as to whether the  prior inventor has suppressed or concealed the invention. However, in  accordance with the statutory presumption in 35 U.S.C. § 282, the  ultimate burden of persuasion remains with the party challenging the  validity of the patent. See Innovative Scuba Concepts, Inc. v. Feder  Indus., Inc., 26 F.3d 1112, 1115, 31 USPQ2d 1132, 1134 (Fed. Cir. 1994)  ("While a patentee may have the burden of going forward with rebuttal  evidence once a challenger presented a prima facie case of invalidity,  the presumption of validity remains intact and the ultimate burden of  proving invalidity remains with the challenger throughout the  litigation." (citing Hybritech, Inc. v. Monoclonal Antibodies, Inc., 802  F.2d 1367, 1376, 231 USPQ 81, 87 (Fed. Cir. 1986))). Once the patentee  has satisfied its burden of production, the party alleging invalidity  under § 102(g) must rebut any alleged suppression or concealment with  clear and convincing evidence to the contrary.


27
Our case law distinguishes between two types of suppression or  concealment. The first is implicated in a situation in which an inventor  actively suppresses or conceals his invention from the public. Fujikawa  v. Wattanasin, 93 F.3d 1559, 1567, 39 USPQ2d 1895, 1901 (Fed. Cir. 1996)  (citing Kendall v. Winsor, 62 U.S. (21 How.) 322, 328 (1858)). The second  involves a legal inference of suppression or concealment based upon an  unreasonable delay in filing a patent application.2 Peeler v.  Miller, 535 F.2d 647, 655, 190 USPQ 117, 122 (1976) (holding that a four-  year delay in filing a patent application after the invention was  perfected was unreasonably long); Shindelar v. Holdeman, 628 F.2d 1337,  1342, 207 USPQ 112, 116 (1980) (finding suppression or concealment  because no reasonable explanation was given for the two-year and five-  month delay between reduction to practice and the filing of a patent  application). The latter type is involved here.


28
Although a prior inventor implicated in a § 102(g) infringement defense  may not have filed a patent application, in contrast to an interference  contestant, that party's delay in otherwise bringing the knowledge of the  invention to the public may nevertheless raise a similar inference of  suppression or concealment. See Int'l Glass Co. v. United States, 408  F.2d 395, 403, 159 USPQ 434, 441 (Ct. Cl. 1969) (holding that the prior  invention of a process did not invalidate a patent on the same process  under § 102(g) because the prior inventor did nothing to make the  invention known to the public). Even though there is no explicit  disclosure requirement in § 102(g), the spirit and policy of the patent  laws encourage an inventor to take steps to ensure that "the public has  gained knowledge of the invention which will insure its preservation in  the public domain" or else run the risk of being dominated by the patent  of another. Palmer v. Dudzik, 481 F.2d 1377, 1387, 178 USPQ 608, 616  (CCPA 1973); see also Kimberly-Clark Corp. v. Johnson & Johnson, 745 F.2d  1437, 1446, 1453, 223 USPQ 603, 607, 614 (Fed. Cir. 1984) (defining § 102  "prior art" to be "technology already available to the public," and  stating that "secret prior art" may not be used to invalidate a patent  under § 102(g)); Oddzon Prods., Inc. v. Just Toys, Inc., 122 F.3d 1396,  1402, 43 USPQ2d 1641, 1645 (Fed. Cir. 1997) ("[W]hen the possessor of  secret prior art (art that has been abandoned, suppressed, or concealed)  that predates the critical date is faced with a later-filed patent, the  later-filed patent should not be invalidated in the face of this `prior' art, which has not been made available to the public. Thus, prior, but  non-public, inventors yield to later inventors who utilize the patent  system."). Absent a satisfactory explanation for the delay or the  presence of other mitigating facts, a prior invention will therefore be  deemed suppressed or concealed within the meaning of § 102(g) "if, within  a reasonable time after completion, no steps are taken to make the  invention publicly known." Int'l Glass, 408 F.2d at 403, 161 USPQ at 441.


29
In the case at hand, we find that Apotex has satisfied its burden of  producing evidence sufficient to create a genuine issue of material fact  that Merck suppressed or concealed its process of manufacturing enalapril  sodium tablets. We emphasize at the outset that although § 102(g) prior  art must be somehow made available to the public in order to defeat  another patent, a § 102(g) prior inventor is under no obligation to file  a patent application. Checkpoint Sys., Inc. v. United States Int'l Trade  Comm'n, 54 F.3d 756, 763, 35 USPQ2d 1042, 1048 (Fed. Cir. 1995). Thus,  while Merck's failure to file a patent application may be relevant to a  determination whether it suppressed or concealed its process, especially  if there were evidence that such failure was based on a decision to  retain the invention as a trade secret, that failure alone does not  satisfy the patentee's burden of producing evidence sufficient to create  a genuine issue of material fact of suppression or concealment. See E.I.  du Pont de Nemours & Co. v. Phillips Petroleum Co., 849 F.2d 1430, 1437,  7 USPQ2d 1129, 1135 (Fed. Cir. 1988) (explaining that a patent  application need not be filed on an invention for it to be considered  § 102(g) prior art as long as the invention is found not to have been  abandoned, suppressed, or concealed).


30
However, Apotex did allege that Merck failed to make its invention  publicly known. Merck perfected its process and began commercially using  the process to manufacture VASOTEC  tablets no later than 1983. Although  Merck argues that its process was disclosed to the public because its  VASOTEC  tablets could have been reverse-engineered, that argument is  based on the admissions of Dr. Sherman, who drew upon the information  provided in Merck's subsequent disclosures to determine the details of  the process.3 Thus, it appears that Merck took no steps to  make the invention publicly known for nearly five years, when it first  published the ingredients used in its process in the 1988 edition of the  Dictionnaire Vidal. We find that such a delay raises an inference that  Merck suppressed or concealed its invention. Accordingly, because Apotex  has successfully discharged its burden of going forward with evidence  creating a genuine issue of material fact of suppression or concealment,  the burden shifts to Merck to rebut that showing by clear and convincing  evidence to the contrary.


31
We conclude that Merck has succeeded in rebutting the inference of  suppression or concealment created by its period of inactivity by clear  and convincing evidence. In Paulik v. Rizkalla, we stated the rule that  "the first inventor will not be barred from relying on later, resumed  activity antedating an opponent's entry into the field, merely because  the work done before the delay was sufficient to amount to a reduction to  practice." 760 F.2d 1270, 1275, 226 USPQ 224, 228 (Fed. Cir. 1985)  (holding that the inference of suppression or concealment from a four-  year delay between reduction to practice and the filing of a patent  application was overcome by the first inventor's resumption of activity  before the second inventor's date of conception). Thus, even though Merck  may have suppressed or concealed the process for a period of time after  it reduced it to practice in 1983, as long as it "resumed activity"  (i.e., made the benefits of its invention known to the public) before  Apotex's entry into the field, it cannot be deemed to have suppressed or  concealed the invention within the meaning of § 102(g).


32
Merck made several disclosures following its period of suppression or  concealment that made the invention publicly known, all of which took  place before Apotex's entry into the field (here, Dr. Sherman's alleged  conception in April of 1994). First, Merck disclosed the ingredients used  in manufacturing VASOTEC  tablets in the 1988 edition of the Dictionnaire  Vidal. It also widely distributed the product monograph in Canada from  October 1992 through 1994, which similarly disclosed the ingredients it  used in its manufacturing process. Merck also provided a step-by-step  description of the process through the testimony given by Brian McLeod at  the Canadian trial on March 28, 1994.


33
Apotex argues that these disclosures inadequately described Merck's  process of manufacturing VASOTEC  tablets, and therefore that the public  never received the benefit of the invention. However, Dr. Sherman  admitted both in his deposition in this case and in his 1994 Statement of  Facts prepared for the Canadian trial that his inspection of the VASOTEC   tablets that Merck sold commercially revealed that they were made using a  wet granulation process. He also admitted that, after learning of the  disclosed starting ingredients from the Canadian product monograph (which  included sodium bicarbonate), it "immediately occurred" to him and was  "obvious to any knowledgeable formulator or chemist" that the final  enalapril sodium product in the VASOTEC  tablets was the result of an  acid-base chemical reaction between enalapril maleate and sodium  bicarbonate in water. Merck's various disclosures, in conjunction with  Apotex's admissions, therefore clearly and convincingly prove that Merck  made the knowledge of its invention available to the public, thereby  satisfying its burden of rebutting Apotex's evidence of suppression or  concealment.


34
Moreover, Apotex's argument that Merck suppressed or concealed the  process by submitting misleading information to the FDA in 1983 is  irrelevant because any suppression that was implicated was overcome by  Merck's subsequent activity. We therefore conclude that the district  court did not err in granting summary judgment that the '780 and '962  patents are invalid under § 102(g).


35
We have considered Apotex's remaining arguments and find them to be  unpersuasive.

CONCLUSION

36
Because the district court did not err in granting summary judgment that  the '780 and '962 patents are invalid under 35 U.S.C. § 102(g), we


37
AFFIRM.



Notes:


1
 Generally  speaking,  the  presumption  of validity does not apply to patents involved in interference proceedings, and thus  the  invalidity  of  a patent involved in an interference under § 102(g)Generally  speaking,  the  presumption  of validity  need only be proven by  preponderant  evidence.   See Bruning    161 F.3d 681, 686, 48 USPQ2d 1934, 1938 (Fed. Cir.  1998) (holding that,   in an interference involving a patent issued from an  application  that,   was  co-pending  with  the  interfering  application,  the  appropriate,   standard  of  proof  for validity challenges is the preponderance of the   evidence standard because  the presumption of validity is inapplicable).   However, the presumption may  effectively be implicated in the case of a   priority contest between an issued  patent  and  an application that was   filed after the issuance of the patent.  In such a situation, the junior  party  must  establish  priority  of invention by clear  and  convincing  evidence.  Price v. Symsek,  988  F.2d  1187, 1194, 26 USPQ2d 1031, 1036se,erally  speaking,  the  presumption  of validity  (Fed. Cir. 1993).  Such a factual scenario is not before us.


2
 A  subset of the category of "inferred" suppression  or  concealment  arises  in  a  situation in which the first inventor is A  subset of the category of "inferred" suppression  "spurred" into filing a patent application by another application, Mason  v. Hepburn, 13 App.D.C. 86 (D.C.  Cir.  1898),  or  by  the  commercial, Mason  activity of another, Woofter v. Carlson, 367 F.2d 436, 445-446, 151 USPQ  407, 416 (CCPA 1967).  This case does not involve "spurring."


3
 It  is  worth  noting  that   suppression  Merck's  process  could  be  reverse-engineered by one of ordinary skill. It  is  worth  noting  that  through an inspection of VASOTEC  tablets, Apotex could not benefit from  the inference of suppression or  concealment  because Merck could not be said to have delayed in making the benefits of  its  invention  known to the public.  See Palmer, 481 F.2d at 1386-87, 178 USPQ  at  615 (stating is  worth  noting  that     that  a  commercial  use  of  an  invention  will  preclude a finding of  615 (stating is  worth  noting  that    suppression or concealment only when such use enables  the  public  to  615 (stating is  worth  noting  that learn of the invention).


