       NOTE: This disposition is nonprecedential.


  United States Court of Appeals
      for the Federal Circuit
                ______________________

                  JOHN R. WILSON,
                     Appellant

                           v.

   GREGORY ROGER MARTIN, ALLISON JEAN
                  TANNER,
                   Appellees
            ______________________

                      2018-1980
                ______________________

    Appeal from the United States Patent and Trademark
Office, Patent Trial and Appeal Board in No. 106,060.
                  ______________________

               Decided: October 21, 2019
                ______________________

    DEVAN V. PADMANABHAN, Padmanabhan & Dawson,
PLLC, Minneapolis, MN, argued for appellant. Also repre-
sented by ERIN DUNGAN, PAUL J. ROBBENNOLT, SRI
SANKARAN.

    LINDA T. COBERLY, Winston & Strawn LLP, Chicago,
IL, argued for appellees. Also represented by KIMBALL
RICHARD ANDERSON; MICHAEL L. GOLDMAN, ANDREW PETER
ZAPPIA, Pepper Hamilton LLP, Rochester, NY.
                ______________________
2                                            WILSON v. MARTIN




    Before PROST, Chief Judge, REYNA and STOLL, Circuit
                          Judges.
REYNA, Circuit Judge.
    John R. Wilson appeals from a decision of the Patent
Trial and Appeal Board in an interference proceeding find-
ing certain claims of U.S Patent No. 8,809,044 unpatenta-
ble as anticipated or obvious. Because substantial evidence
supports the Board’s finding that the prior art discloses the
claimed “ambient gas” limitation, and the Board did not
abuse its discretion by refusing to apply judicial estoppel,
we affirm.
                        BACKGROUND
        I. The ’044 Patent and the ’267 Application
     John R. Wilson is the listed inventor on U.S. Patent No.
8,809,044 (“the ’044 patent”), which is entitled “Highly Ef-
ficient Gas Permeable Devices and Methods for Culturing
Cells.” The ’044 patent, assigned to Wilson Wolf Manufac-
turing Corporation, is directed to methods of using gas-per-
meable devices to culture animal cells. ’044 patent,
Abstract; J.A. 8. The ’044 patent teaches that cells are gen-
erally cultured in the presence of oxygenated gas and a liq-
uid culture medium that provides the cells with nutrients.
See id. col. 3 ll. 37–47. The ’044 patent describes a cell cul-
ture device having multiple vertical shelves containing two
or more culture compartments into which cells and a cul-
ture medium are placed. Id. col. 4 ll. 36–38, col. 8 ll. 41–
48, col. 12 ll. 47–54. The culture compartments are con-
nected by a manifold and include an access port through
which cells and medium are added or removed. Id. col. 9 ll.
20–22. These compartments include at least one wall that
is comprised of a gas-permeable material and are sepa-
rated by a space which contains oxygenated gas. Id. col. 8
ll. 42–45. This gas passes through the gas-permeable por-
tions of the culture compartment and delivers oxygen to the
WILSON v. MARTIN                                            3



cells. Id. col. 10 ll. 17–21. The ’044 patent discloses that
this oxygenated gas is preferably “ambient gas.” Id. col. 9
ll. 35–37.
    Figure 3 of the ’044 patent illustrates an embodiment
of this cell culture device, where oxygenated gas 100 flows
from gas space 50 to cells 90 placed within culture compart-
ments 20:




Id. Fig. 3, col. 10 ll. 17–21.
    Gregory Roger Martin and Allison Jean Tanner (collec-
tively, “Martin”) are the listed inventors on U.S. Patent Ap-
plication No. 14/814,267, entitled “Multilayered Cell
Culture Apparatus” and published as U.S. Patent Applica-
tion Publication No. 2015/0337252 on November 26, 2015
(“the ’267 application”). The ’267 application was filed by
Corning Incorporated (“Corning”). Like the ’044 patent,
the ’267 application is also directed to a cell culture device
with two or more culture compartments comprised of a gas-
permeable material that permits the delivery of oxygen-
ated gas to the cells being cultured within. ’267 applica-
tion, ¶ 11.
    Every claim at issue in this appeal requires that the
cells are cultured in the presence of “ambient gas.” Inde-
pendent claim 1 of the ’044 patent corresponds to the inter-
ference count and recites:
4                                          WILSON v. MARTIN




    1. A method of culturing animal cells in a gas per-
    meable multi-shelf cell culture apparatus, the
    method comprising:
       adding animal cells and media into a gas
       permeable multi-shelf apparatus compris-
       ing two or more culture compartments,
       each compartment including a shelf com-
       prised of gas permeable, liquid impermea-
       ble material for cells to reside upon, each
       shelf connected to an opposing surface, a
       fluid pathway shared by said culture com-
       partments, and each said shelf is in contact
       with a gas space,
       whereby said apparatus is incubated in the
       presence of ambient gas suitable for animal
       cell culture, oriented in a position such that
       said culture compartments are located one
       above the other, each said shelf is in a hor-
       izontal position with said gas space located
       below it, animal cells reside upon at least a
       portion of each said shelf, said culture com-
       partments include media in contact with
       said shelf and said opposing surface, and
       ambient gas resides within each said gas
       space and is in contact with each shelf.
’044 patent col. 30 ll. 18–37 (emphasis added).
    Independent claim 2 of the ’267 application, which is
almost identical to claim 1 of the ’044 patent, corresponds
to the interference count and recites:
    2. A method of culturing cells in a gas permeable
    multi-shelf cell culture apparatus, the method com-
    prising:
       adding cells and media into a gas permea-
       ble multi-shelf apparatus comprising two
       or more culture compartments, each
WILSON v. MARTIN                                           5



        compartment including a shelf comprised
        of gas permeable, liquid impermeable ma-
        terial for cells to reside upon, each shelf
        connected to an opposing surface, a fluid
        pathway shared by said culture compart-
        ments, and each said shelf is in contact
        with a gas space,
        whereby said apparatus is incubated in the
        presence of ambient gas suitable for cell cul-
        ture, oriented in a position such that said
        culture compartments are located one
        above the other, each said shelf is in a hor-
        izontal position with said gas space located
        below it, cells reside upon at least a portion
        of each said shelf, said culture compart-
        ments include media in contact with said
        shelf and said opposing surface, and ambi-
        ent gas resides within each said gas space
        and is in contact with each shelf.
’267 application at 7.
                         II. Toner
     U.S. Patent No. 6,759,245 (“Toner”), entitled “Cell Cul-
ture Systems and Methods for Organ Assist Devices,” is di-
rected to systems and methods for culturing animal cells
using modular cell culturing devices with gas-permeable
membranes. J.A. 1540 (Toner col. 1 ll. 20–21, col. 2 ll. 35–
36, 51–53). Toner teaches that by using a gas-permeable,
liquid-impermeable membrane for the culture compart-
ment, the delivery of oxygen to the cells may be separated
from delivery of the culture medium. J.A. 1540, 1542
(Toner col. 2 ll. 36–43, col. 5 ll. 52–53). To deliver oxygen
to the cells, Toner discloses using an “oxygenated fluid,”
and explains that “[o]xygenated fluids can be gases or liq-
uids, and can include air . . . and other gasses commonly
found in nature.” J.A. 1543 (Toner col. 7 ll. 63–65, col. 8
ll. 3–9). Toner further discloses that the oxygenated fluid
6                                           WILSON v. MARTIN




can be supplied to the interior of the culture compartment
“through an opening,” such as “a port or manifold.” Id.
(Toner col. 8 ll. 43–51). “Other ports” may be also added
“for air displacement” or “for venting oxygenated fluids.”
J.A. 1549 (Toner col. 19 ll. 43–46, 50–53). The flow of oxy-
genated fluid through the interior of the cell culture device
“can be static, in any one direction, or in multiple direc-
tions.” J.A. 1548 (Toner col. 17 ll. 1–2).
     Toner’s Figures 8a and 8b are relevant to this appeal.
Figure 8a illustrates a preferred embodiment of Toner’s
cell culture device with three culture compartments:




J.A. 1526 (Toner Fig. 8a). Each of the three culture com-
partments illustrated in Figure 8a includes a gas-permea-
ble, liquid-impermeable membrane 30 to hold the cultured
cells 40, a compartment 10 to hold biological liquid nutri-
tion for the cells, and a rigid, impermeable housing 50. J.A.
1549 (Toner col. 19 ll. 30–35). Inlet port 3 and outlet port
3’ are used to conduct the oxygenated fluid into and out of
the common oxygenated fluid compartment 222, where the
oxygenated fluid comes into contact with membranes 30,
thereby delivering oxygen to the cells. Id. (Toner col. 19 ll.
35–37). Inlet port 5 and outlet port 5’ are used for the bio-
logical liquid, which is delivered to each culture
WILSON v. MARTIN                                           7



compartment via manifold 555 and is removed via manifold
555’. Id. (Toner col. 19 ll. 37–43). “Other ports for venting
oxygenated fluids may also be added to the impermeable
wall 505 of the bioreactor 1.” Id. (Toner col. 19 ll. 52–53).
    Toner’s Figure 8b illustrates an alternate embodiment,
where instead of a common oxygenated fluid compartment
222, each cell culture compartment includes its own sepa-
rate oxygenated fluid compartment 20:




J.A. 1527 (Toner Fig. 8b); see also J.A. 1549 (Toner col. 19
ll. 56–61).
            III. Proceedings Before the Board
    On November 25, 2015, Martin requested an interfer-
ence between the ’044 patent and the ’267 application un-
der 35 U.S.C. § 135(a). 1 The Patent Trial and Appeal



    1    The Leahy–Smith America Invents Act (“AIA”)
eliminated interference proceedings. See Pub. L. No. 112–
29, § 3, 125 Stat. 284, 285–93 (2011). Because the ’044 pa-
tent and the ’267 application both have effective filing
dates prior to March 16, 2013, the effective date of the AIA,
they are subject to patent laws in effect prior to the AIA.
8                                          WILSON v. MARTIN




Board (“the Board”) 2 declared the interference on October
31, 2016. Claims 1–45 of the ’044 patent and claims 2–45
of the ’267 application correspond to the interference
count. 3 J.A. 5.
    During the interference, Martin filed a motion with the
Board, arguing that claims 1–5, 7–10, 12–14, 16–20, 22–23,
25–26, 28–30, 33–37, 39–42, and 44–45 of the ’044 patent
are invalid as anticipated under 35 U.S.C. § 102(b) 4 by
Toner. J.A. 10. In support of its motion, Martin submitted
two declarations by its expert, Dr. Crespi. J.A. 13. Wilson
opposed Martin’s motion, relying on his own testimony as
an expert witness. J.A. 16.




Pre-AIA § 135(a) provided that “[w]henever an application
is made for a patent which, in the opinion of the Director
[of the U.S. Patent and Trademark Office], would interfere
with any pending application, or with any unexpired pa-
tent, an interference may be declared . . . . The Board of
Patent Appeals and Interferences shall determine ques-
tions of priority of the inventions and may determine ques-
tions of patentability.” 35 U.S.C. § 135(a) (2006).
     2   The AIA renamed the Board of Patent Appeals and
Interferences as the Patent Trial and Appeal Board. Pub.
L. No. 112–29, § 6, 125 Stat. at 313.
     3   Claims 46–49 of the ’044 patent were not part of
the interference. Claim 1 of the ’267 application was pre-
viously cancelled. These claims are not at issue in this ap-
peal.
     4   The Pre-AIA version of § 102(b) applies to this ap-
peal. Pre-AIA § 102(b) provided that “[a] person shall be
entitled to a patent unless . . . the invention was patented
or described in a printed publication in this or a foreign
country . . . more than one year prior to the date of the ap-
plication for patent in the United States.” 35 U.S.C.
§ 102(b) (2006).
WILSON v. MARTIN                                            9



    In its motion, Martin proposed a construction for the
term “ambient gas,” seeking to limit its meaning to a “gas
of the environment surrounding and external to the multi-
shelf apparatus.” J.A. 17. Wilson opposed this construc-
tion, proposing instead that the term should be construed
to mean a “gas that encompasses and contacts the external
surfaces of the cell culture device and has a particular set
of characteristics.” J.A. 16. The Board did not construe the
term, finding that Toner discloses the “ambient gas” limi-
tation under either of the proposed constructions. J.A. 18.
     The Board found that Toner’s Figure 8a discloses “mul-
tiple ports which communicate between the interior and ex-
terior of the device” and that “would allow for outside air to
enter the device.” J.A. 18–19. The Board noted that Toner
discloses an oxygenated fluid that “is typically gas and may
be ‘air,’” and explained that “[a]ir passing from the exterior
of the device into the interior of the device is ‘ambient gas’
under either of the proposed constructions.” J.A. 18. The
Board pointed to Dr. Crespi’s testimony, which stated that
the presence of additional ports in Toner’s Figure 8a “in-
dicat[ed] ‘that the common gas space inside the device is
open to the ambient environment for venting air or the mix-
ture of air with other gases supplied into the gas space via
the inlet.” Id. (quoting J.A. 1385 (Crespi Second Decl.
¶ 90)).
    The Board rejected Wilson’s argument that Toner does
not teach the “ambient gas” limitation because Toner re-
quires the gas to be pumped or forced into the device. The
Board explained that Toner’s disclosure of “static, as well
as directional, flow of the oxygenated fluid” demonstrates
that Toner’s oxygenated fluid does not need to be pumped
or forced. Id. (citing J.A. 1379–80, 1385 (Crespi Second
Decl. ¶¶ 74, 76, 90)). The Board also rejected Wilson’s ar-
gument that Toner’s oxygenated fluid is not “ambient gas”
because Toner contemplates oxygenated fluid with care-
fully controlled characteristics different from “those found
in standard ambient cell culture conditions.” J.A. 20
10                                          WILSON v. MARTIN




(quoting J.A. 658–59 (Wilson Third Opposition at 6:23–7:7,
7:14–8:9)). The Board explained that the claims of the ’044
patent do not require the “ambient gas” to have any specific
characteristics, but only require “that the gas be ‘ambient.’”
Id. The Board conceded that Toner does not use the word
“ambient,” but explained that Toner nonetheless antici-
pates this limitation because it is “inherent or otherwise
implicit” in Toner. J.A. 19–20 (quoting Standard Havens
Prods., Inc. v. Gencor Indus., Inc., 953 F.2d 1360, 1369
(Fed. Cir. 1991) (internal quotation marks omitted)).
     The Board also refused to apply judicial estoppel to pre-
vent Martin from asserting that Toner discloses the “ambi-
ent gas” limitation, rejecting Wilson’s argument that
Martin’s position in this case is inconsistent with state-
ments made by Corning 5 during prosecution of a parent ap-
plication to the ’267 application. J.A. 20. The Board found
that Corning previously argued only that Toner disclosed a
“closed oxygen chamber,” not that Toner excluded the pres-
ence of “ambient gas.” J.A. 21. The Board further found
that Corning “acknowledged that Toner allowed for the
flow of oxygenated fluids and [argued] only that these flu-
ids ‘may be’ pressurized.” Id. The Board also explained
that it based its decision on a different evidentiary record
than the one involved in the prior prosecution proceeding,
because the Board had before it the testimony of both par-
ties’ experts. Id.
    On the basis of the above findings, and having further
determined that the prior art disclosed the remaining lim-
itations of the claims at issue, the Board issued a decision
on Martin’s motion and a judgment on December 26, 2017,




     5  Corning is the real party in interest behind the ’267
application. J.A. 7.
WILSON v. MARTIN                                           11



finding claims 1–45 of the ’044 patent invalid as antici-
pated or obvious. 6 J.A. 2, 22–24.
     After the Board’s decision, Wilson requested a rehear-
ing, arguing that the Board erred because Toner requires
its oxygenated fluid to be sourced from a physically con-
nected gas tank, and because Toner’s additional ports only
permit the oxygenated fluid to exit from the culture device,
not enter it. J.A. 32. The Board denied rehearing, rejecting
both arguments. Relying on Dr. Crespi’s testimony, the
Board found that Toner does not contemplate an external
gas tank as the only supply of the oxygenated fluid.
J.A. 33–35. The Board further found that the claims of the
’044 patent do not require the ambient gas to move from
outside of the culture device to its interior, explaining that
its decision therefore did not rest on the presence of other
ports that permit air to enter the culture device. J.A. 36.
   Wilson timely appealed. We have jurisdiction under 28
U.S.C. § 1295(a)(4)(A).
                        DISCUSSION
    Wilson challenges both the Board’s conclusions regard-
ing anticipation under 35 U.S.C. § 102(b) and its refusal to
apply judicial estoppel. We address each issue in turn.




    6    The Board found that claims 6, 11, 15, 21, 24, 27,
31–32, 38, and 43 of the ’044 patent were obvious under 35
U.S.C. § 103(a) in view of Toner or Toner and other prior
art. The Board also invalidated as anticipated or obvious
all of the claims of the ’267 application on the same bases
it invalidated claims 1–45 of the ’044 patent, finding that
Martin did not rebut the presumption that these claims
were invalid in view of the same prior art. J.A. 2; see 37
C.F.R. § 41.207(c). These rulings are not at issue in this
appeal.
12                                          WILSON v. MARTIN




         I. Anticipation Under 35 U.S.C. § 102(b)
     In interference proceedings, we review the Board’s le-
gal conclusions de novo and its factual findings for substan-
tial evidence. Bd. of Trustees of Leland Stanford Junior
Univ. v. Chinese Univ. of Hong Kong, 860 F.3d 1367, 1375
(Fed. Cir. 2017) (citing In re Elsner, 381 F.3d 1125, 1127
(Fed. Cir. 2004) and In re Gartside, 203 F.3d 1305, 1313–
15 (Fed. Cir. 2000)). Substantial evidence is “such relevant
evidence as a reasonable mind might accept as adequate to
support a conclusion.” Gartside, 203 F.3d at 1312 (quoting
Consol. Edison Co. of N.Y. v. NLRB, 305 U.S. 197, 229
(1938)). “Where two different conclusions may be war-
ranted based on the evidence of record, the Board’s decision
to favor one conclusion over the other is the type of decision
that must be sustained by this court as supported by sub-
stantial evidence.” In re Bayer Aktiengesellschaft, 488 F.3d
960, 970 (Fed. Cir. 2007) (citing In re Jolley, 308 F.3d 1317,
1329 (Fed. Cir. 2002)).
    Anticipation is a question of fact that we review for sub-
stantial evidence. HTC Corp. v. Cellular Commc’ns Equip.,
LLC, 877 F.3d 1361, 1368 (Fed. Cir. 2017). For a prior art
reference to anticipate, it must disclose all elements of the
claim “within the four corners of the document.” Net Mon-
eyIn, Inc. v. VeriSign, Inc., 545 F.3d 1359, 1369 (Fed. Cir.
2008).
    Wilson’s sole argument concerning anticipation is that
Toner does not disclose the “ambient gas” limitation. The
Board found that Wilson did not challenge Toner’s disclo-
sure of any other limitation. J.A. 15, 32. Thus, resolution
of the anticipation issue on appeal turns solely on whether
substantial evidence supports the Board’s findings that
Toner discloses the “ambient gas” limitation. We conclude
that it does.
    The Board found that Toner discloses using an oxygen-
ated fluid that “is typically gas and may be ‘air,’” and ex-
plained that “[a]ir passing from the exterior of the device
WILSON v. MARTIN                                           13



into the interior of the device is ‘ambient gas’ under either
of the proposed constructions.” J.A. 18 (citing Toner col. 8
ll. 1–9); see also J.A. 33. The Board also found that Toner
does not require that its oxygenated fluid “be pumped or
forced into the device.” J.A. 18, 34. The Board credited Dr.
Crespi’s testimony that Toner “allows for static . . . flow of
the oxygenated fluid,” which “results in a device having the
‘ambient gas’ limitation of the Wilson claims.” J.A. 18 (cit-
ing J.A. 1385 (Crespi Second Decl. ¶ 90)). The Board fur-
ther pointed to Dr. Crespi’s testimony that Toner’s device
“can include ‘[o]ther ports for venting oxygenated fluids’
and the use of static oxygenated fluids indicating ‘that the
common gas space inside the device is open to the ambient
environment for venting air or the mixture of air with other
gases supplied into the gas space via the inlet.’” Id. (quot-
ing J.A. 1385 (Crespi Second Decl. ¶ 90) (internal citations
omitted)). The Board explained that “these other ports
would allow for ambient gas to enter the device.” J.A. 19.
The Board found this expert testimony “convincing.”
J.A. 15. This is substantial evidence that supports the
Board’s findings.
    The majority of Wilson’s arguments on appeal concern-
ing anticipation are grounded in its assertion that Toner
cannot disclose the “ambient gas” limitation because the
oxygenated fluid in Toner must come from a physically con-
nected gas tank. According to Wilson, “every embodiment
described in Toner discloses the use of the opposite of am-
bient gas—gas from a gas tank that has a specific mixture,
pressure, and flow rate that can be manipulated or con-
trolled.” Appellant’s Br. 32; see also id. at 35–36, 40–43,
45; Reply Br. 22–26. On the basis of this assertion, Wilson
argues that the Board’s findings that Toner discloses “am-
bient gas” are not supported by substantial evidence. We
disagree for two reasons.
     First, the Board’s findings are supported by Toner’s
written description and figures. Toner’s Figure 8a plainly
illustrates an embodiment of Toner’s invention without a
14                                          WILSON v. MARTIN




connected gas tank. J.A. 1526 (Toner Fig. 8a). Toner’s
written description of Figure 8a likewise does not include
any discussion of a connected gas tank. J.A. 1549 (Toner
col. 19 ll. 30–55). In addition, when describing a different
embodiment illustrated in Toner’s Figure 1, which does in-
clude a connected gas tank (“oxygenated fluid source 4”),
Toner teaches that the gas tank is only “preferabl[e]”—not
required, as Wilson contends. J.A. 1543 (Toner col. 8,
ll. 45–49). Thus, Toner’s written description and figures
support the Board’s determination that Toner does not re-
quire its oxygenated fluid to be sourced from a gas tank.
    Second, Dr. Crespi’s testimony, on which the Board re-
lied when it rejected the same argument, supports the
Board’s findings. Dr. Crespi’s testimony states that the
culture device in Toner’s Figure 8 “is not shown connected
to a pressurized air source (i.e., a gas cylinder).” J.A. 1385
(Crespi Second Decl. ¶ 90) (cited by J.A. 18–19, 34–35). Dr.
Crespi also testified that the oxygenated fluid inside
Toner’s device illustrated in Figure 8a can be “static” while
the interior of the device is open to the exterior environ-
ment via “[o]ther ports for venting oxygenated fluids.”
J.A. 18 (quoting J.A. 1385 (Crespi Second Decl. ¶ 90) (in-
ternal citations omitted)). This suggests that a pressurized
gas tank is not required because the pressure inside and
outside Toner’s device in this embodiment would the same.
Dr. Crespi also explained his opinion as a person of ordi-
nary skill in the art that “the large volume of gas space rel-
ative to the cell culture cartridges, pressurized gas flow is
not actually needed for the device” illustrated in Toner’s
Figure 8a. Lastly, in denying rehearing, the Board ex-
plained that it also credited Dr. Crespi’s deposition testi-
mony “that one skilled in the art would have recognized
that the device of Figure 8[a] of Toner could be used as a
freestanding device and would not have required the gas
tank found in the Figure 1 configuration of Toner.” J.A. 35.
   Wilson argues that Dr. Crespi’s above testimony
should not be given any weight. We recognize, however,
WILSON v. MARTIN                                            15



that the Board was entitled to weigh and credit that testi-
mony. Elbit Sys. of Am., LLC v. Thales Visionix, Inc., 881
F.3d 1354, 1358 (Fed. Cir. 2018); see also Inwood Labs., Inc.
v. Ives Labs., Inc., 456 U.S. 844, 856 (1982) (“Determining
the weight and credibility of the evidence is the special
province of the trier of fact.”); Yorkey v. Diab, 601 F.3d
1279, 1284 (Fed. Cir. 2010) (“We defer to the Board’s find-
ings concerning the credibility of expert witnesses.”). Alt-
hough Toner’s disclosure of an embodiment that includes a
gas tank (illustrated in Toner’s Figure 1) may support a
different conclusion than the one reached by the Board, “it
is not for us to second-guess the Board’s assessment of the
evidence,” but rather “to determine whether substantial
evidence supports the conclusion chosen by the Board.” Ve-
lander v. Garner, 348 F.3d 1359, 1378–79 (Fed. Cir. 2003).
Here, the relevant evidence is such that a reasonable mind
might accept as adequate to support the Board’s conclu-
sion. See Fleming v. Escort Inc., 774 F.3d 1371, 1375 (Fed.
Cir. 2014) (“Substantial evidence is such relevant evidence
as reasonable minds might accept as adequate to support a
conclusion even if it is possible to draw two inconsistent
conclusions from the evidence.” (internal quotation marks
and citation omitted)).
     Wilson raises other arguments that we find unpersua-
sive. For example, Wilson argues that it was improper as
a matter of law for the Board to rely on Dr. Crespi’s testi-
mony because, according to Wilson, that testimony was ex-
trinsic evidence improperly used “to fill the gaps” in Toner
and “to provide missing disclosure.” Appellant’s Br. 39–40.
Wilson contends that Dr. Crespi’s testimony “reache[d] be-
yond the four corners of Toner” by introducing disclosures
not found in Toner, such as “the use of a gas pump or fan
to circulate gas to the oxygenated fluid compartment,” the
presence of a “large volume of gas space relative to the cell
culture cartridges,” and “the use of the device of [Toner’s]
Figure 8a . . . as a ‘freestanding device.’” Id.; Reply Br. 21.
On this basis, Wilson argues that Dr. Crespi’s testimony is
16                                         WILSON v. MARTIN




not substantial evidence that could support the Board’s de-
cisions. See Reply Br. 15.
     We have previously explained that “[e]xtrinsic evi-
dence may be used to interpret the allegedly anticipating
reference and to shed light on what it would have meant to
a person of ordinary skill in the art.” Monsanto Tech. LLC
v. E.I. DuPont de Nemours & Co., 878 F.3d 1336, 1345 (Fed.
Cir. 2018) (citing In re Baxter Travenol Labs., 952 F.2d 388,
390 (Fed. Cir. 1991)) (internal alterations and quotation
marks omitted). The purpose of extrinsic evidence in an
anticipation analysis “is to educate the decision-maker to
what the reference meant to persons of ordinary skill in the
field of the invention, not to fill gaps in the reference.”
Scripps Clinic & Research Found. v. Genentech, Inc., 927
F.2d 1565, 1576 (Fed. Cir. 1991), overruled on other
grounds by Abbott Labs. v. Sandoz, Inc., 566 F.3d 1282
(Fed. Cir. 2009).
     We conclude that that Board did not err by relying on
Dr. Crespi’s testimony. None of Dr. Crespi’s statements to
which Wilson directs us introduced elements or limitations
claimed in the ’044 patent but missing from Toner. Specif-
ically, the claims of the ’044 patent do not require “a gas
pump or fan” for circulation, “a large volume of gas space
relative to the cell culture cartridges,” or a “freestanding
device.” Appellant’s Br. 39–40; Reply Br. 21. Thus,
whether these elements are missing from Toner is irrele-
vant to the Board’s anticipation analysis. See TF3 Ltd. v.
Tre Milano, LLC, 894 F.3d 1366, 1374 (Fed. Cir. 2018)
(“Anticipation requires that all of the claim elements and
their limitations are shown in a single prior art reference.”
(emphasis added) (quoting In re Skvorecz, 580 F.3d 1262,
1266 (Fed. Cir. 2009))). Because Dr. Crespi was not at-
tempting to “provide missing disclosure of the claimed in-
vention,” the Board was entitled to rely on his testimony to
understand what Toner meant to a person of ordinary skill
in the art, which is entirely consistent with our precedent.
Scripps, 927 F.2d 1565 at 1577.
WILSON v. MARTIN                                            17



    Wilson next challenges the Board’s finding that the
“air” disclosed in Toner is the same as “ambient gas” under
either of the parties’ proposed constructions. Appellant’s
Br. 41–43 (citing J.A. 18, 33). Wilson asserts that the air
disclosed in Toner is “always supplied under pressure, from
a physically connected source of gas.” Id. at 41; see also id.
at 43. According to Wilson, such air would therefore not
meet the “ambient gas” limitation under its proposed con-
struction because “it would not have the same ‘particular
set of characteristics’ as the ‘gas that encompasses and con-
tacts the external surfaces of the cell culture device.’” Id.
at 42. This argument fails because it also relies on the er-
roneous assumption that Toner requires the use of a gas
tank. In addition, the Board’s finding is supported by Dr.
Crespi’s testimony, which states that based on Toner’s dis-
closure of using air as the oxygenated fluid, “the gas inside
the common gas space (222), delivered via the inlet (3),
would be the same as the ambient gas (i.e., air . . . ).” J.A.
1385 (Crespi Second Decl. ¶ 90) (cited by J.A. 18). Wilson
also concedes that Toner does not require any specific loca-
tion from which its air must originate (and neither do the
claims of the ’044 patent). Id. Thus, even if a gas tank
were required, it could be filled with the air outside the cul-
ture device, thereby ensuring that the air in the tank had
the same “particular set of characteristics.” See id.
    Wilson also contends that the air disclosed in Toner
does not meet the “ambient gas” limitation under Martin’s
proposed construction either, because the air does not orig-
inate from the “immediately surrounding environment” of
the culture device. Id. This argument is misplaced because
Martin’s proposed construction only requires the air to
originate from the “environment surrounding and exter-
nal” to the culture device. J.A. 17. There is no requirement
that the air originates from the immediately surrounding
environment.
   Lastly, Wilson argues that the Board’s finding that gas
may enter from the exterior of Toner’s device through
18                                           WILSON v. MARTIN




“other ports” is not supported by substantial evidence be-
cause these ports only permit the oxygenated fluid inside
the device to exit. Appellant’s Br. 46–47. The Board clari-
fied in its decision denying rehearing, however, that its
prior decision did not indicate that “ambient gas must
move from the exterior of the device to the interior of the
device” through these “other ports.” J.A. 36. Rather, as the
Board explained, ambient gas only had to “resid[e] within
each gas space.” Id. Dr. Crespi’s testimony likewise states
that Toner’s oxygenated fluid is “supplied into the gas
space via the inlet.” J.A. 1385 (Crespi Second Decl. ¶ 90).
Thus, even if Wilson is correct that Toner’s “other ports” do
not permit “ambient gas” to enter its device, that does not
alter our conclusion that the Board’s findings are sup-
ported by substantial evidence.
    We conclude that substantial evidence supports the
Board’s final determination that Toner discloses the “am-
bient gas” limitation.
                    II. Judicial Estoppel
     The doctrine of judicial estoppel provides that “where a
party successfully urges a particular position in a legal pro-
ceeding, it is estopped from taking a contrary position in a
subsequent proceeding where its interests have changed.”
Data Gen. Corp. v. Johnson, 78 F.3d 1556, 1565 (Fed. Cir.
1996) (citing Davis v. Wakelee, 156 U.S. 680, 689 (1895)).
The Board has authority and discretion to apply the doc-
trine of judicial estoppel. Id.; see New Hampshire v. Maine,
532 U.S. 742, 750 (2001) (“[J]udicial estoppel is an equita-
ble doctrine invoked by a court at its discretion.” (internal
quotation marks omitted)). To decide whether to apply ju-
dicial estoppel, courts typically consider several factors, in-
cluding (1) whether a party’s later position is “clearly
inconsistent” with its earlier position; (2) whether a court
has accepted the party’s prior position, such that accepting
its “inconsistent position in a later proceeding would create
the perception that either the first or the second court was
WILSON v. MARTIN                                           19



misled”; and (3) whether the party changing its position
“would derive an unfair advantage or impose an unfair det-
riment on the opposing party if not estopped.” New Hamp-
shire, 532 U.S. at 751 (internal quotation marks and
citations omitted). “Additional considerations may inform
the doctrine’s application in specific factual contexts.” Id.
    We review the Board’s refusal to apply the doctrine for
abuse of discretion. Id. The Board abuses its discretion
when it makes “a clear error of judgment in weighing the
relevant factors” or bases its decision “on an error of law or
clearly erroneous factual findings.” ArcelorMittal Atlan-
tique et Lorraine v. AK Steel Corp., 908 F.3d 1267, 1277
(Fed. Cir. 2018).
    Wilson argues on appeal that the Board abused its dis-
cretion by refusing to judicially estop Martin from arguing
that Toner discloses the “ambient gas” limitation. Wilson
contends that application of the judicial estoppel doctrine
was warranted in this case because during prior prosecu-
tion of a parent application to the ’267 application, Corn-
ing, the real party in interest behind Martin, made
statements that allegedly are inconsistent with Martin’s
position in this case. Specifically, Wilson points to Corn-
ing’s response to a non-final rejection of its prior applica-
tion, in which Corning stated that “Toner discloses a ‘closed
oxygen chamber’” that permits “users [to] ‘control and ma-
nipulate’ the gas delivered to the device,” and argues that
a closed oxygen chamber cannot be open to “ambient gas.”
Appellant’s Br. 19. Wilson further asserts that accepting
Martin’s current position that Toner discloses “ambient
gas” would lead to the perception that “either the patent
examiner or the Board was misled,” and would provide an
unfair advantage to Corning. Appellant’s Br. 24 (capitali-
zation removed). We disagree for two reasons.
   First, Corning’s statements to which Wilson directs us
were made with respect to a different embodiment of
Toner’s invention than the one on which the Board relied
20                                          WILSON v. MARTIN




in this case. Specifically, the Examiner rejected Corning’s
prior application as anticipated by Toner’s Figure 8b—not
Figure 8a. See J.A. 2922. This difference is significant be-
cause Toner’s Figure 8b illustrates an embodiment in
which each cell culture compartment has its own separate
oxygenated fluid compartment, and the interior of the cell
culture device itself is closed off from the external environ-
ment. See J.A. 1527 (Toner Fig. 8b); J.A. 1549 (Toner col.
19 ll. 56–61). By contrast, Figure 8a—the figure on which
Martin and the Board relied in this case—illustrates an
embodiment that includes a common oxygenated fluid com-
partment with inlet and outlet ports open to the external
environment. Thus, Corning’s prior statements that
Toner’s Figure 8b illustrated a “closed oxygen chamber” are
not inconsistent with Martin’s current position that
Toner’s Figure 8a discloses an open oxygen chamber that
contains “ambient gas.”
    Wilson attempts to overcome this flaw in its argument
by asserting that the Examiner cited to both Figures 8a
and 8b in rejecting Corning’s prior application on obvious-
ness grounds. Reply Br. 10 (citing J.A. 2923–24). Accord-
ing to Wilson, Corning’s statements therefore “must also be
interpreted as being directed to Toner in general, including
Figure 8a.” Id. The Examiner only cited Figure 8a, how-
ever, as support for Toner’s disclosure that its cell culture
compartments “are separated slightly in the apparatus.”
J.A. 2924. Because this disclosure has no connection to
Toner’s disclosure of oxygenated fluid compartments in ei-
ther figure, Corning’s statements were plainly not directed
to Toner’s Figure 8a.
    Second, we agree with the Board that Martin’s current
position is not clearly inconsistent with Corning’s prior
statements because those statements were made in a dif-
ferent context and were part of a different evidentiary rec-
ord. Specifically, the claims in Corning’s prior application
were directed to structural components of the cell culture
compartment, instead of cell culture conditions like the
WILSON v. MARTIN                                        21



presence of “ambient gas.” See J.A. 21, 37, 2928, 2955. The
claims of Corning’s prior application also did not include
the “ambient gas” limitation. Lastly, the Examiner review-
ing Corning’s prior application did not have the benefit of
Dr. Crespi’s testimony. We have previously refused to ap-
ply judicial estoppel in circumstances where the contexts
surrounding a party’s allegedly inconsistent positions were
markedly different. See Akamai Tech. v. Limelight Net-
works, Inc., 805 F.3d 1368, 1378 (Fed. Cir. 2015). On this
record, where the context and record in the prior proceed-
ing is likewise markedly different from this case, we con-
clude that the Board did not abuse its discretion by
refusing to apply judicial estoppel.
                       CONCLUSION
    We have considered Wilson’s remaining arguments
and find them unpersuasive. We conclude that the Board’s
findings that Toner discloses the “ambient gas” limitation
and therefore anticipates claims 1–5, 7–10, 12–14, 16–20,
22, 23, 25, 26, 28–30, 33–37, 39–42, 44, and 45 of the ’044
patent are supported by substantial evidence. We further
conclude that the Board did not abuse its discretion by re-
fusing to apply judicial estoppel. We therefore affirm the
Board’s order and decisions cancelling claims 1–45 of the
’044 patent and claims 2–45 of the ’267 application.
                      AFFIRMED
                          COSTS
   Costs to Martin.
