Ex Parte Barenholz et al

Patent Trial and Appeal Board

Jul 25, 2014

10314487 (P.T.A.B. Jul. 25, 2014)

UNITED STATES PATENT AND TRADEMARK OFFICE
UNITED STATES DEPARTMENT OF COMMERCE
United States Patent and Trademark Office
Address: COMMISSIONER FOR PATENTS
P.O. Box 1450
Alexandria, Virginia 22313-1450
www.uspto.gov
APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO.
10/314,487 12/05/2002 Yechezkel Barenholz 9550-0004 9784
20855 7590 07/25/2014
PASTERNAK PATENT LAW
1900 EMBARCADERO ROAD
SUITE 211
PALO ALTO, CA 94303
EXAMINER
WESTERBERG, NISSA M
ART UNIT PAPER NUMBER
1618
MAIL DATE DELIVERY MODE
07/25/2014 PAPER
Please find below and/or attached an Office communication concerning this application or proceeding.
The time period for reply, if any, is set in the attached communication.
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
__________

BEFORE THE PATENT TRIAL AND APPEAL BOARD
__________

Ex parte YECHEZKEL BARENHOLZ and
VERONICA WASSERMAN
__________

Appeal 2012-004019
Application 10/314,487
Technology Center 1600
__________

Before DONALD E. ADAMS, LORA M. GREEN, and
JEFFREY N. FREDMAN, Administrative Patent Judges.

FREDMAN, Administrative Patent Judge.

DECISION ON APPEAL
This is an appeal1 under 35 U.S.C. § 134 involving claims to a
liposomal composition. The Examiner rejected the claims as obvious. We
have jurisdiction under 35 U.S.C. § 6(b). We affirm.

1 Appellants identify the Real Party in Interest as Yissum Research
Development Company of the Hebrew University of Jerusalem
(see App. Br. 2).
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Statement of the Case
Background
“The present invention relates to the therapeutic use of tempamine for
treating conditions caused by cellular oxidative damage or cellular oxidation
stress. In a particular embodiment, the invention relates to a liposome
composition having entrapped tempamine” (Spec. 1, ll. 6-8).
The Claims
Claims 1, 4-9, 12-19, and 24 are on appeal. Claim 1 is representative
and reads as follows:
1. A composition comprising liposomes comprised of a
vesicle-forming lipid and between about 1-20 mole percent
of a lipid derivatized with a hydrophilic polymer and
between 2 and 500 mM of tempamine entrapped in said
liposomes.

The issues
A. The Examiner rejected claims 1, 4-9, and 12-15 under 35 U.S.C.
§ 103(a) as obvious over Mehlhorn,2 Hahn,3 and Guo4 (Ans. 5-8).
B. The Examiner rejected claims 16, 17, 19, and 24 under 35 U.S.C.
§ 103(a) as obvious over Mehlhorn, Hahn, Guo, Hsia,5 and Ryan6 (Ans. 8-
10).

2 Mehlhorn, R., US 5,827,532, issued Oct. 27, 1998.
3 Hahn et al., Identification of Nitroxide Radioprotectors, 132
RADIATION RES. 87-93 (1992).
4 Guo et al., US 5,972,379, issued Oct. 26, 1999.
5 Hsia, J., US 5,817,632, issued Oct. 6, 1998.
6 Ryan et al., US 4,544,545, issued Oct. 1, 1985.
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C. The Examiner rejected claim 18 under 35 U.S.C. § 103(a) as obvious
over Mehlhorn, Hahn, Guo, Hsia, Ryan, and Allen7 (Ans. 11-12).
A. 35 U.S.C. § 103(a) over Mehlhorn, Hahn, and Guo
The Examiner finds that “Mehlhorn discloses liposomes in which
ionizable hydrophobic compounds (e.g., drugs or bioactive agents) are
accumulated by transmembrane pH gradients after the compounds have been
phosphorylated . . . . In example 1, soybean lipid liposome containing 50
µM tempamine was prepared” (Ans. 5). The Examiner finds that
“Tempamine was one of two nitroxides that exhibited greater
radioprotection than tempol on an equimolar basis . . . . A concentration of
10 mM tempamine was used to study X-ray dose-survival of Chinese
hamster cells” (Ans. 5-6). The Examiner finds that Hahn teaches that
“nitroxides exhibit superoxide dismutase (SOD) activity, protect mammalian
cells from cytotoxicity induced by hydrogen peroxide and superoxide and
appear to be protectors against a variety of oxidative stresses such as
radiation” (Ans. 5).
The Examiner finds that Guo teaches “liposomes composed of a
vesicle-forming lipid and between 1-20 mole percent of a lipid derivatized
with a hydrophilic polymer and entrapped within the liposome, a drug
conjugate” (Ans. 6). The Examiner finds that Guo teaches that “[s]urface
coating with hydrophilic polymer chains enhances the time the liposomes
remain circulating in the blood stream” (Ans. 6).
The Examiner finds it obvious to “incorporate tempamine at higher
levels in liposomes . . . [because] higher concentration (e.g., 10 mM) is

7 Allen et al., US 5,527,528, issued Jun. 18, 1996.
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required to provide protection against oxidative stress, as described by
Hahn” (Ans. 7). The Examiner also finds it obvious “to add 1 - 20 mole
percent of a hydrophilic polymer lipid derivative and cholesterol to the
liposome as these ingredients increase the circulation lifetime of the
liposomes stabilize the phospholipid vesicles or liposomes” (Ans. 8).
The issue with respect to this rejection is: Does the evidence of
record support the Examiner’s conclusion that Mehlhorn, Hahn, and Guo
render the claims obvious?
Findings of Fact
1. Mehlhorn teaches that “processes whereby ionizable
hydrophobic compounds, such as, for example, drugs, bioactive agents and
other chemical species, can be accumulated into liposomes having different
internal and external pH's (transmembrane pH gradients) after the
compounds have been phosphorylated” (Mehlhorn, col. 6, ll. 39-44).
2. Mehlhorn teaches that
Spin-labelled amines and carboxylic acids (amines and acids
labelled with nitroxide free radicals) such as Tempamine
and Tempacid have been used as probes to measure the pH
gradient. The probes are freely permeable in their
uncharged form to the membranes and the relative
concentration of the probes within the vesicles provided a
direct measurement of the pH gradient.

(Mehlhorn, col. 6, ll. 53-60.)
3. Mehlhorn teaches that “[l]iposomes may be provided or
administered to patients in a variety of methods which are well known in the
art. For example, liposomes may be administered parenterally, orally,
topically or by injection. Various modes of injection include
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intramuscularly, subcutaneously or intravenously” (Mehlhorn, col. 7, ll. 61-
65).
4. Mehlhorn teaches that “[l]iposomes of soybean lipids were
prepared . . . . Spin-labeled primary amine Tempamine . . . was added [and]
. . . sodium hydroxide was also added to the solution to raise the pH of the
solution to 7.4. This resulted in a 300-fold accumulation of the Tempamine
inside the vesicles within one minute of the addition of the base” (Mehlhorn,
col. 11, ll. 16-26).
5. Hahn teaches that “nitroxides exhibit superoxide dismutase
activity . . . nitroxides protect mammalian cells from cytotoxicity induced
by hydrogen peroxide and superoxide . . . some nitroxides can readily
penetrate intracellular spaces” (Hahn 87, col. 2).
6. Hahn teaches that “Tempol protects mammalian cells against
radiation-induced cytotoxicity in vitro and can afford protection in vivo
against whole-body irradiation . . . . Tempamine . . . exhibited greater
radioprotection than Tempol” (Hahn 87, col. 2).
7. Hahn teaches that the “search for effective radioprotective
agents remains an important objective because of the potential for harm from
excessive radiation exposure from an accident or manned space exploration,
or from damage to normal tissues entailed in radiation therapy” (Hahn 87,
col. 1-2).
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8. Tempamine panel of Figure 1 of Hahn is reproduced below:

FIG. 1. Full X-ray dose-survival curves for selected
nitroxides. Chinese hamster V79 cells were pretreated 10
min prior to X irradiation with selected nitroxides at a
concentration of 10 mM under aerobic conditions. The
curve for nitroxide (closed circles) is compared to the curve
for control cells (open circles). Significance levels for each
curve for nitroxide compared to the curve for survival of
control cells were as follows: Tempamine, P = 0.0011

(Hahn 88, Figure 1 legend).
9. Hahn teaches that “Chinese hamster V79 cells were grown in
F12 medium . . . . The nitroxides were added to exponentially growing cells
(final concentration of nitroxide is indicated in text and figures) at room
temperature 10 min prior to X irradiation” (Hahn 88, col. 1).
10. Guo teaches a composition “for treatment of a bacterial
infection. The composition includes liposomes composed of a vesicle-
forming lipid and between 1-20 mole percent of a lipid derivatized with a
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hydrophilic polymer, and, entrapped within the liposomes, a drug- conjugate
having anti-bacterial activity and composed of ciprofioxacin covalently
attached to an amino acid” (Guo, col. 2, ll. 60-67).
11. Guo teaches that:
“Long-circulating” liposomes as used herein refers to
liposomes having a surface coating of hydrophilic polymer
chains . . . Up to 10% of the injected dose of long-
circulating liposomes remains in the blood stream 24 hours
after injection, in contrast to conventional liposomes, e.g.,
liposomes lacking the coating of polymer chains, which are
cleared from the bloodstream in several hours.

(Guo, col. 4, ll. 52-60.)
12. Guo teaches that “liposomes with a high internal concentration
of drug can be prepared by remote loading. In this technique, a drug is
accumulated in the liposomes’ central compartment in response to an ion
gradient, typically a pH gradient across the liposome bilayer” (Guo, col. 8,
ll. 47-51).
13. Guo teaches that the
[A]mmonium ion gradient provides a number of advantages
in active drug loading . . . drug molecules in non-protonated
form are taken up and protonated within the liposomes . . .
The counterion of the ammonium salt, e.g., sulfate
counterion, may further enhance drug loading, by its ability
to precipitate or form insoluble complexes with the drug
being loaded.

(Guo, col. 10, ll. 5-28.)
14. Guo teaches that the “vesicle-forming lipids of this type are
preferably those having two hydrocarbon tails or chains, typically acyl
groups, and a polar head group. Included in this class are the phospholipids,
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such as phosphatidylcholine (PC) . . . . An exemplary PC is hydrogenated
soy phosphatidylcholine (HSPC)” (Guo, col. 7, ll. 19-28).
15. Guo teaches that the “liposomes may additionally include lipids
that can stabilize a vesicle or liposome composed predominantly of
phospholipids. The most frequently employed lipid from this group is
cholesterol at levels between 25 to 45 mole percent” (Guo, col. 7, ll. 50-54).
16. Guo teaches that a “preferred hydrophilic polymer for use in
coupling to a vesicle forming lipid is polyethylene glycol (PEG)” (Guo, col.
8, ll. 10-11).
Principles of Law
“The combination of familiar elements according to known methods
is likely to be obvious when it does no more than yield predictable results.”
KSR Int’l Co. v. Teleflex Inc., 550 U.S. 398, 416 (2007). “If a person of
ordinary skill can implement a predictable variation, § 103 likely bars its
patentability.” Id. at 417.
Analysis8
Claim 1
Hahn teaches that nitroxides such as tempamine protects cells from
oxidative stresses (FF 5) and that “Tempamine . . . exhibited greater
radioprotection than Tempol” (Hahn 87, col. 2; FF 6). Hahn teaches that
tempamine protected Chinese hamster ovary cells from irradiation when

8 We note that “where the relevant factual inquiries underlying an
obviousness determination are otherwise clear, characterization by
the examiner of prior art as ‘primary’ and ‘secondary’ is merely a
matter of presentation with no legal significance.” In re Mouttet,
686 F.3d 1322, 1333 (Fed. Cir. 2012).
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present “at a concentration of 10 mM under aerobic conditions” (Hahn 88,
Figure 1 legend; FF 8).
Mehlhorn teaches the incorporation of tempamine into liposomes (FF
1, 2, 4) where the liposomes may be “administered to patients in a variety of
methods which are well known in the art” (Mehlhorn, col. 7, ll. 61-62; FF 3).
Guo teaches liposomes “composed of a vesicle-forming lipid and
between 1-20 mole percent of a lipid derivatized with a hydrophilic
polymer” (Guo, col. 2, ll. 62-64; FF 10). Guo teaches that “[u]p to 10% of
the injected dose of long-circulating liposomes remains in the blood stream
24 hours after injection, in contrast to conventional liposomes, e.g.,
liposomes lacking the coating of polymer chains, which are cleared from the
bloodstream in several hours” (Guo, col. 4, ll. 56-60; FF 11).
Applying the KSR standard of obviousness to the findings of fact,
conclude that the person of ordinary skill would have reasonably
incorporated Hahn’s radioprotective tempamine compound (FF 5-9) into a
liposome as taught by Mehlhorn (FF 1-4) including lipid derivatized with a
hydrophilic polymer as taught by Guo (FF 10-16) because patient delivery of
“effective radioprotective agents remains an important objective because of
the potential for harm from excessive radiation exposure from an accident or
manned space exploration, or from damage to normal tissues entailed in
radiation therapy” (Hahn 87, col. 1-2; FF 7). Such a combination is merely a
“predictable use of prior art elements according to their established
functions.” KSR, 550 U.S. at 417.
Appellants contend that “Me[h]lhorn fails completely to teach or
suggest the elements of the claimed liposomes, including (1) liposomes
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comprising unphosphorylated compounds (such as tempamine) at
therapeutic concentrations; (2) liposomes comprising non-hydrophobic
compounds (tempamine) at the recited concentrations; (3) derivatized
liposomes; and (4) methods of using these liposomes to treat oxidative
damage, as claimed” (App. Br. 8). Appellants contend that “it is error for
the Examiner to assert that Mehlhorn’s complete failure to teach or suggest
the claimed elements does not negate the obviousness rejection” (App. Br.
8). Appellants contend that “Guo does not teach or suggest liposomes
comprising tempamine concentrations of 2-500 mM and/or methods of using
these liposomes to treat oxidative damage, as claimed” (App. Br. 9).
Appellants contend that “Hahn also fails to teach or suggest compositions
and methods as claimed. This reference is silent as to liposomes (derivatized
or not) and, accordingly, cannot teach or suggest concentrations of
tempamine entrapped within a liposome” (App. Br. 9).
We find this argument unpersuasive. As the Examiner correctly
pointed out (see Ans. 13), the rejection is not an anticipation rejection solely
relying upon Mehlhorn or Guo or Hahn, but rather is an obviousness
rejection over the combined teachings of Mehlhorn, Hahn, Guo, as well as
“the background knowledge possessed by a person having ordinary skill in
the art.” KSR, 550 U.S. at 418. “It is well-established that a determination
of obviousness based on teachings from multiple references does not require
an actual, physical substitution of elements. . . . Rather, the test for
obviousness is what the combined teachings of the references would have
suggested to those having ordinary skill in the art.” Mouttet, 686 F.3d at
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1332-1333. We conclude that the combined teachings of Mehlhorn, Hahn,
and Guo render claim 1 obvious for the reasons given above.
Appellants contend that “Hahn teaches concentrations of free
tempamine of 1 mM, which is outside of the claimed range. In particular,
Hahn added a 10 mM solution of tempamine to the culture medium of cells
in petri dishes such that the final concentration of tempamine was 1 mM,
which is less than the claimed amount” (App. Br. 9).
We find this argument unpersuasive. While Appellants are correct
that Hahn teaches the use of a final 1mM concentration of tempamine in the
“Electron Paramagnetic Resonance” experiments (see Hahn 88, col. 2),
Hahn teaches the use of a final concentration of 10 mM tempamine in the
radiation survival experiments (see Hahn 88, Figure 1 legend; FF 8).
The Examiner finds it obvious “to incorporate tempamine at higher
levels in liposomes than th[e] 50 µM used by Mehlhorn to prepare liposomes
that protect against oxidative stress” since a “higher concentration (e.g., 10
mM) is required to provide protection against oxidative stress, as described
by Hahn” (Ans. 7). The Examiner recognizes that it “would have been
customary for an artisan of ordinary skill to determine the optimal amount of
tempamine to add to the liposome in order to best achieve the desired
results” (Ans. 7). See In re Aller, 220 F.2d 454, 456 (CCPA 1955). The
Examiner also finds it obvious “to add 1 - 20 mole percent of a hydrophilic
polymer lipid derivative and cholesterol to the liposome as these ingredients
increase the circulation lifetime of the liposomes stabilize the phospholipid
vesicles or liposomes, respectively, as taught by Guo” (Ans. 8). This
explicit analysis by the Examiner provides “an apparent reason to combine
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the known elements in the fashion claimed by the patent at issue.” KSR, 550
U.S. at 418. This is also consistent with the recent non-precedential decision
in In re Patel, 2014 WL 3454231 *4 (Fed. Cir. 2014) (“a rejection based on
ranges approaching each other might well be appropriate where there is a
teaching in the prior art that the end points of the prior art range are
approximate, or can be flexibly applied”). Therefore, we are not persuaded
by Appellants contention that “the Examiner has not provided articulated
reasoning why the cited references lead the skilled artisan would use
tempamine at the claimed concentrations in derivatized liposomes, as
claimed” (App. Br. 10).
Appellants contend that “the skilled artisan reading these references
would have absolutely no expectation that the claimed liposomes could be
successfully made and/or used to treat oxid[]ative damage in cells” (App. Br.
11).
We are not persuaded. Appellants provide no evidence suggesting
any unpredictability in combining the disclosures of Mehlhorn, Hahn, and
Guo. In the absence of any unpredictability, we conclude that there would
be at least a reasonable expectation that the ordinary artisan would have
been able to incorporate tempamine into liposomes using the method taught
by both Mehlhorn (FF 4) and Guo (FF 12-13) for the purpose of
radioprotection taught by Hahn (FF 5-7) using the amounts of tempamine
taught by Hahn (FF 5-6) and the lipid derivatization to enhance circulation
time taught by Guo (FF 11). Kubin stated that, “[r]esponding to concerns
about uncertainty in the prior art influencing the purported success of the
claimed combination, this court [in O’Farrell] stated: ‘[o]bviousness does
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not require absolute predictability of success . . . all that is required is a
reasonable expectation of success.”’ In re Kubin, 561 F.3d 1351, 1360 (Fed.
Cir. 2009) (citing In re O’Farrell, 853 F.2d 894, 903-904 (Fed. Cir. 1988)).
Appellants contend that “[m]odifying Me[h]lhorn’s liposomes to
contain therapeutic concentrations of tempamine would destroy this
reference’s intended function of using tempamine as a pH probe” (App. Br.
12).
We are not persuaded. “The test for obviousness is not whether the
features of a secondary reference may be bodily incorporated into the
structure of the primary reference . . . . Rather, the test is what the combined
teachings of the references would have suggested to those of ordinary skill
in the art.” In re Keller, 642 F.2d 413, 425 (CCPA 1981). The Examiner’s
rejection is not based on a bodily incorporation of Mehlhorn, Hahn, and
Guo, but rather their combined teachings which suggest incorporation of
tempamine into liposomes for treatment as a radioprotective agent (FF 1-13).
Thus, the ordinary artisan would have selected an amount of tempamine
sufficient to achieve this goal, starting with the 10 mM value taught by Hahn
(FF 8). See Aller, 220 F.2d at 456.
Appellants contend that “Guo teaches away from the liposome
formulations in that this reference requires (1) the liposome treat bacterial
infection and (2) that drug entrapped within the liposome must be covalently
attached to an amino acid” (Reply Br. 8).
We are not persuaded. A teaching away requires a reference to
actually criticize, discredit, or otherwise discourage the claimed solution.
See In re Fulton, 391 F.3d 1195, 1201 (Fed. Cir. 2004) (“The prior art’s
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mere disclosure of more than one alternative does not constitute a teaching
away from any of these alternatives because such disclosure does not
criticize, discredit, or otherwise discourage the solution claimed”).
Appellants do not identify, and we do not find, any teaching in Guo (or
Mehlhorn or Hahn) which criticizes or discourages the liposome
formulations incorporating tempamine.
Claims 4-8 and 12-15
Appellants contend that
Guo, the only reference that teaches anything about
derivatized liposomes, fails entirely to teach anything about
liposomes with entrapped tempamine, including the
concentration of tempamine sufficient to achieve
precipitation in the presence of an entrapped counter ion
(claim 4) where the counter ion is a sulfate ion (claim 8);
tempamine-entrapped in a liposome comprising 1-20 mole
percent of a hydrophilic polymer and cholesterol (claim 5)
or a liposome comprising hydrogenated phosphatidylcholine
(claim 6); and/or tempamine entrapped in a liposome
comprising polyethylene glycol (claim 7).

(App. Br. 15.)
The Examiner finds that
Guo states that the counterion of the ammonium salt, e.g.
sulfate counterion, may further enhance drug loading by the
counter ion’s ability to precipitate or form insoluble
complexes with the drug being loaded (col 10, ln 25 - 28).
The failure to teach encapsulation of tempamine at
millimolar concentrations is remedied by the combined
teachings of drug delivery liposomes by Mehlhorn and the
therapeutic usefulness of 10 mM tempamine as taught by
Hahn.

(Ans. 16.)
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We find that the Examiner has the better position. As the Examiner
pointed out, Guo teaches that the “counterion of the ammonium salt, e.g.,
sulfate counterion, may further enhance drug loading, by its ability to
precipitate or form insoluble complexes with the drug being loaded” (Guo,
col. 10, ll. 25-28; FF 13). Guo is suggesting precipitation of the compound
of interest, here tempamine as taught by Hahn and Mehlhorn, using a sulfate
counterion, addressing the requirements of claims 4 and 12 (FF 13). Guo
also suggests incorporation of cholesterol in liposomes as required by claims
5 and 14 (Ans. 6; FF 15), as well as hydrogenated phosphatidyl choline
required by claims 6 and 13 (Ans. 6; FF 14). Finally, Guo also teaches the
use of polyethylene glycol in claims 7 and 15 (Ans. 6; FF 16).
Conclusion of Law
The evidence of record supports the Examiner’s conclusion that
Mehlhorn, Hahn, and Guo render the claims obvious.
B. and C. 35 U.S.C. § 103(a) rejections
Claims 16-19 and 24
The Examiner provides specific evidence and reasons supporting the
obviousness of these claims (see Ans. 8-12).
Appellants simply recite the limitations of these claims without
providing any specific argument as to why these limitations distinguish over
the cited prior art. Merely stating the different limitations of dependent
claims does not constitute separate argument. See 37 C.F.R. § 1.192(c)(7);
In re Dance, 160 F.3d 1339, 1340 n.2 (Fed. Cir. 1998) (“Although Dance
mentions the content of the dependent claims, he does not argue their merits
separately from those of independent claim 33, or attempt to distinguish
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them from the prior art. . . . Therefore, all claims stand or fall together with
claim 33.)
SUMMARY
In summary, we affirm the rejection of claims 1, 4-9, and 12-15 under
35 U.S.C. § 103(a) as obvious over Mehlhorn, Hahn, and Guo.
We affirm the rejection of claims 16, 17, 19, and 24 under 35 U.S.C.
§ 103(a) as obvious over Mehlhorn, Hahn, Guo, Hsia, and Ryan.
We affirm the rejection of claim 18 under 35 U.S.C. § 103(a) as
obvious over Mehlhorn, Hahn, Guo, Hsia, Ryan, and Allen.
No time period for taking any subsequent action in connection with
this appeal may be extended under 37 C.F.R. § 1.136(a).

AFFIRMED

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