00:00:00
we can see in near real time whether a
00:00:03
non-athlete has sustained a particularly
00:00:05
big hit or a lot of hits and we can kind
00:00:08
of get ahead of the problem by saying
00:00:09
hey player X has sustained a really big
00:00:11
hit let's pull them aside just see how
00:00:14
they're doing this is the Discovery
00:00:16
files podcast from the US National
00:00:18
Science Foundation I'm Nate podker in
00:00:20
the United States 15 of high school
00:00:22
athletes are affected by concussions
00:00:24
every year according to the CDC and
00:00:26
repeated head impacts can have
00:00:28
devastating long-term neurological
00:00:29
consequences Nicholas checky is a PhD
00:00:32
student in bioengineering at Stanford
00:00:34
University who is working to make
00:00:36
contact Sports a little safer for
00:00:38
athletes at all levels of play thank you
00:00:40
so much for joining us today thanks Nate
00:00:42
for having me appreciate it so I want to
00:00:45
start with going back a little bit
00:00:47
um what Drew you into investigating
00:00:49
brain injury
00:00:50
yeah so I've always been really
00:00:53
passionate about sports it was a big
00:00:55
part of my upbringing um and even into
00:00:57
young adulthood I've continued playing
00:00:58
sports uh when I was studying my
00:01:01
mechanical engineering degree at UC
00:01:03
Irvine
00:01:05
um I kind of didn't know what I wanted
00:01:06
to do with my career at the time but I
00:01:08
was still playing sports I was really
00:01:10
involved in water polo my second year of
00:01:13
college I sustained a pretty serious
00:01:15
concussion at a practice during water
00:01:18
polo and
00:01:20
um it just so happened kind of
00:01:22
coincidental timing there was a
00:01:24
professor at UC Irvine Dr Jim Hicks who
00:01:27
was leading the world's first study on
00:01:29
head impacts and concussion in water
00:01:31
polo specifically so movie timing
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perfect timing so me being the sports
00:01:38
Aficionado and playing water polo and
00:01:40
having the recent brain injury I reached
00:01:42
out to him and quickly got involved in
00:01:45
the research and had that kind of
00:01:47
personal experience with the sport and
00:01:49
the injury to kind of drive my motive
00:01:50
Nation to continue that research that
00:01:54
was about a decade ago and I haven't
00:01:56
looked back since then I've been working
00:01:57
in protective headgear development and
00:01:59
concussion research sense
00:02:01
so thinking about repetitive head
00:02:04
injuries what kind of long-term effects
00:02:08
are there
00:02:09
yeah so it really
00:02:13
um depends on how severe your TBI is uh
00:02:17
traumatic brain injury TBI so
00:02:20
the range of traumatic brain injuries is
00:02:23
pretty wide so some can be as severe as
00:02:26
causing death or lifelong disabilities
00:02:28
and there are also extreme injuries that
00:02:31
can be recovered from like skull
00:02:33
fractures or brain bleeds
00:02:35
our lab at Stanford we mostly look at
00:02:37
concussion right now concussion symptoms
00:02:40
are usually things like headaches nausea
00:02:43
blurred vision sensitivity to light
00:02:45
maybe slurred speech changes in mood and
00:02:49
behavior there's a lot of different
00:02:50
symptoms that can come with it these
00:02:53
symptoms can last on the scale of a few
00:02:56
days for very mild concussions but even
00:02:58
last up to several months in manifest as
00:03:01
post-concussive syndrome now concussions
00:03:04
aren't the only problem though there's
00:03:07
actually sub-concussive impacts which
00:03:09
won't present with any immediate
00:03:11
symptoms but the cumulative burden of
00:03:14
these repeated subconcussive head
00:03:16
impacts like football players sustain
00:03:18
over the lifetime of a career have been
00:03:21
linked to later life depression and
00:03:23
neurodegenerative diseases so you can
00:03:25
have immediate symptoms but these are
00:03:27
also symptoms that can kind of creep up
00:03:29
on you later in life so it's important
00:03:31
that for all types of these brain
00:03:33
injuries we're making an effort to stay
00:03:34
ahead of it
00:03:36
right I think that awareness of the
00:03:37
small
00:03:38
or the what we think of as a smaller
00:03:40
impacts is important I think we've had a
00:03:42
couple pretty well-known football
00:03:44
players in the last decade or two that
00:03:47
after they pass they found all kinds of
00:03:50
strange things going on with their brain
00:03:51
exactly so what are the challenges to
00:03:56
detecting traumatic brain injuries
00:03:58
yeah so if you have a really severe
00:04:01
traumatic brain injury like those skull
00:04:03
fractures or brain bleeds uh you can
00:04:05
usually go into a doctor's office and
00:04:08
those will be able to be detected with
00:04:10
medical tool or medical imaging tools
00:04:12
like CT scans or MRI if you have a mild
00:04:16
concussion it's not so clear-cut of a
00:04:19
process so usually concussions are
00:04:21
diagnosed through symptom reporting so
00:04:24
you'll sustain an impact you'll show up
00:04:27
at the doctor and say hey I've been
00:04:28
having headaches I have trouble sleeping
00:04:30
sensitivity to light whatever your
00:04:32
symptoms are and then they'll say based
00:04:33
on those symptoms you probably have a
00:04:36
concussion there's no real clear-cut
00:04:40
objective way to say this is guaranteed
00:04:44
to be a concussion right now
00:04:46
with the sub-concussive impacts it's
00:04:48
even harder because those don't present
00:04:51
with any with any symptoms so we kind of
00:04:53
don't know at this time how many is too
00:04:56
many impacts how hard of an impact was
00:04:58
too hard of an impact so our lab has
00:05:01
actually developed instrumented mouth
00:05:03
guard technology
00:05:04
where we have these mouth guard devices
00:05:07
like a mouth guard that athletes would
00:05:09
normally wear during their normal sport
00:05:11
participation but on the inside we have
00:05:14
these soft flexible circuit boards that
00:05:17
have an accelerometer and gyroscope on
00:05:19
the inside
00:05:20
so the athletes will be wearing these
00:05:23
instrumented mouth guards during their
00:05:25
normal sport participation and we can
00:05:27
see in near real time whether a
00:05:30
non-athlete has sustained a particularly
00:05:31
big hit or a lot of hits and we can kind
00:05:34
of get ahead of the problem by saying
00:05:36
hey player X has sustained a really big
00:05:38
hit let's pull them aside just see how
00:05:40
they're doing maybe give them a rest
00:05:42
maybe before any of those big symptoms
00:05:44
occur the problem with this technology
00:05:47
though is that there's no clearly
00:05:50
defined
00:05:51
biomechanical threshold for concussion
00:05:54
or serious side effects of head impacts
00:05:57
yet so this isn't this can't be used as
00:05:59
a diagnostic tool yet
00:06:01
right you're really just establishing
00:06:04
what the numbers you're even looking at
00:06:06
are like building the data set that
00:06:08
anything that could be used for that in
00:06:11
the future would build off of yeah what
00:06:15
was testing that product out in the
00:06:16
field like
00:06:17
yeah so
00:06:19
um we obviously had to get players to
00:06:22
buy into wearing this um it did take
00:06:24
some time to get it to a place where it
00:06:26
was comfortable and felt the same as the
00:06:28
normal mouth guards but we were actually
00:06:31
able to gather a lot of really
00:06:32
interesting data with these mouth guard
00:06:34
devices the most interesting thing that
00:06:36
we were able to gather was uh
00:06:39
information on how helmets were
00:06:42
performing on the field because there's
00:06:44
a lot that goes on in the lab that we do
00:06:47
to test helmets but we never really
00:06:49
follow up too much on how they're
00:06:51
performing on the field and really
00:06:52
really interestingly in one of our
00:06:55
studies from a couple years ago with the
00:06:57
mouth guard data we saw that helmets
00:07:00
that performed significantly different
00:07:02
from one another in the lab didn't
00:07:04
actually perform differently on the
00:07:06
field they performed about the same and
00:07:09
so really what I think we're seeing
00:07:10
there is the need to develop a totally
00:07:13
revolutionary technology that isn't just
00:07:15
an incremental step change but it goes a
00:07:18
long long ways to make a big impact in
00:07:20
safety that will actually be able to
00:07:22
observe not just in the controlled
00:07:24
perfect lab environment but on the field
00:07:27
as well
00:07:28
so as you're moving into this current
00:07:32
paper and this current research why
00:07:34
liquid shock absorbers you know
00:07:37
yeah so great question uh there's a lot
00:07:40
of different technologies that are used
00:07:42
in helmets for a variety of applications
00:07:46
um but the one thing that remains true
00:07:48
for helmets is there's limited space and
00:07:50
a helmet we can't just make a huge
00:07:52
pillow helmet as big as we want we need
00:07:55
to choose a shock absorber that will
00:07:58
give protection for all kinds of impacts
00:08:00
because especially in football we have
00:08:02
those slow small repeated head impacts
00:08:04
and then we get some big ones that are
00:08:06
going to cause concussions or more
00:08:08
serious events
00:08:09
so traditionally Foams have been used in
00:08:13
helmets and the Foams that are used
00:08:15
exert a force based on how much they're
00:08:18
compressed now this isn't ideal because
00:08:21
it leads to phones being tuned for a
00:08:24
very specific range of impacts so if the
00:08:27
foam is tuned for a really slow impact
00:08:29
the foam is going to compress down and
00:08:31
reach its maximum compression too early
00:08:33
and it'll bottom out that means the foam
00:08:35
won't be able to do any more work and
00:08:37
will lead to a high spike in the impact
00:08:39
Force when a fast impact comes now if a
00:08:42
foam is tuned for a really severe impact
00:08:44
like a concussive impact it'll make the
00:08:47
Foam too stiff to help for the repeated
00:08:50
subconcussive impacts that are slower
00:08:52
that'll build up over a lifetime
00:08:54
so the reason we chose liquid is because
00:08:57
we needed a technology that's adaptive
00:09:00
to different velocities the liquid shock
00:09:03
absorbers that we've made like this one
00:09:05
here this is a prototype that we've got
00:09:08
was inspired by the hydraulic shock
00:09:10
absorbers that are used in for example
00:09:13
your vehicle's suspension system so
00:09:16
hydraulic shock absorbers can adapt to
00:09:18
provide a soft response at different
00:09:21
velocities
00:09:22
however in a helmet we obviously can't
00:09:25
have big rigid metal components like you
00:09:27
have in your vehicle's suspension system
00:09:29
so our design uses kind of the same
00:09:32
principles of hydraulic shock absorption
00:09:34
but is made out of all soft components
00:09:37
so we've got on the outside a high
00:09:39
strength fabric that surrounds a liquid
00:09:42
that's contained in a central chamber
00:09:44
when the shock is compressed
00:09:46
fluid ejects out laterally to a part in
00:09:49
the helmet that presumably would not be
00:09:51
under impact and then after the impact
00:09:54
is over that fluid comes back into the
00:09:56
central chamber
00:09:58
uh now one more thing is there actually
00:10:00
are some films that can adapt their
00:10:03
response to different velocities like
00:10:04
viscoelastic Foams uh however their
00:10:08
performance is really sensitive to
00:10:10
changes in temperature so if you get too
00:10:13
hot those Foams get really really soft
00:10:15
if you get too cold the foam is really
00:10:17
stiffen up and they don't work like
00:10:19
they're supposed to now what we what
00:10:21
we've observed in our some of our
00:10:23
experimental studies
00:10:24
is that as long as we're not picking a
00:10:26
fluid that freezes like water or
00:10:29
evaporates with temperature changes
00:10:31
we've observed pretty consistent results
00:10:34
when we change the temperature of the
00:10:36
impacted environment so we're still
00:10:37
getting that adaptive response in a wide
00:10:39
range of settings
00:10:41
that set me up to ask you what kind of
00:10:44
liquid is in there yeah so right now
00:10:47
we're using uh it's called propylene
00:10:50
glycol so it's used in a lot of
00:10:52
cosmetics and even the food industry but
00:10:54
we've also looked at things like mineral
00:10:56
oil or just other liquids that won't
00:10:59
have they'll have a particularly low
00:11:01
freezing point because helmets are used
00:11:03
in all sorts of applications like snow
00:11:05
helmets or military helmets Etc
00:11:09
so
00:11:10
I think this is this question's more
00:11:12
philosophical I guess how important is
00:11:15
modeling
00:11:17
as you're developing a product
00:11:19
yeah
00:11:20
um so I'll be honest I don't think
00:11:23
modeling is a necessity to building a
00:11:25
new product but it certainly can help
00:11:28
save a lot of time and money especially
00:11:31
when we're developing a new technology
00:11:32
like ours that is just like nothing at
00:11:36
all that's on the market today usually
00:11:38
in helmets you've got plastic structures
00:11:40
or Foams and we're trying to put liquid
00:11:43
in a helmet so the real benefit to
00:11:46
modeling is that we can run a series of
00:11:50
simulations that change the material
00:11:52
Properties or the shape or size of our
00:11:54
device and we can run that series of
00:11:56
simulations overnight or maybe you know
00:11:59
over the course of a few days whereas if
00:12:01
we wanted to get a manufacturer to make
00:12:04
a bunch of prototypes for us that have
00:12:06
all those changes it would maybe take
00:12:08
weeks or months and thousands of dollars
00:12:10
the other benefit of the simulation and
00:12:14
modeling environment is that it's really
00:12:16
really controlled and while that might
00:12:17
not be exactly what happens in the real
00:12:19
world if we're trying to get to the
00:12:21
bottom of why we're seeing the results
00:12:23
that we're seeing we can go back and
00:12:25
replay the simulation over and over
00:12:27
again and kind of see and pinpoint why
00:12:30
did we get the result that we got rather
00:12:32
than if we have a prototype that's not
00:12:33
perfect and then it breaks we have to
00:12:35
remake it we have to rerun the
00:12:37
experiment all over again
00:12:39
right can you talk a little bit about
00:12:41
how you guys test things in the
00:12:43
laboratory there
00:12:45
yeah so we pretty much have two main
00:12:48
test setups one is for testing helmet
00:12:52
materials at the kind of component level
00:12:53
we want to see how does the shell how
00:12:55
does the shock absorber how does the
00:12:57
Comfort padding all respond to a unit
00:13:00
axial impact and then we've also got
00:13:02
full helmet tests where we've got
00:13:04
helmets that are fit onto a crash test
00:13:06
dummy and a big impact Ram that goes and
00:13:09
slams into them at velocities
00:13:11
representative of concussions on the
00:13:14
field for the helmet shock absorber test
00:13:17
those component level tests we're really
00:13:19
just looking at how does the material
00:13:21
itself behave when different sorts of
00:13:24
loading is are our input to that shock
00:13:28
absorber system for the helmet tests
00:13:30
we're looking at what happens to the
00:13:32
head and brain and neck when a full
00:13:35
helmet system is placed on that dummy
00:13:38
in your opinion could we zero out
00:13:41
concussive risk with the right kind of
00:13:44
helmet
00:13:45
yeah so it's a lofty goal for sure
00:13:49
but I do think that it's possible
00:13:52
um if we look back several decades at
00:13:57
school fractures and more serious
00:13:59
life-threatening head injuries it used
00:14:01
to be quite common in sport uh football
00:14:04
um but once the right injury metrics
00:14:06
were used to evaluate those risks and
00:14:09
standardized testing organizations like
00:14:11
noxy implemented regulations for helmet
00:14:15
Technologies to advance and meet certain
00:14:17
safety criteria it nearly eliminated
00:14:20
that type of injury those skull
00:14:21
fractures we don't really see those
00:14:24
hardly at all in football anymore so I
00:14:27
think this is something that we could
00:14:30
see with concussions one day but I will
00:14:32
say I think with concussion specifically
00:14:36
it's not going to be as simple as
00:14:38
developing a new technology or setting a
00:14:41
new crite or injury risk criteria that
00:14:43
immediately just solves all the problems
00:14:45
technology is definitely a major part of
00:14:49
the solution but you're going to need a
00:14:51
kind of multi-pronged approach to
00:14:54
solving concussion and right now I think
00:14:55
that would first start with better
00:14:57
helmet technology but also you're going
00:14:59
to need rule changes that promote safer
00:15:01
gameplay you're going to need constant
00:15:03
monitoring with things like instrumented
00:15:05
mouth guards to remove players who are
00:15:07
taking too much to or too much burden
00:15:09
and also just improved education for
00:15:12
athletes coaches training staff to
00:15:15
really let everybody know how how
00:15:17
serious concussion is
00:15:19
right and it's it's like you mentioned
00:15:22
earlier that a lot of it is
00:15:23
self-reported and you're talking about
00:15:26
the symptoms that you're experiencing so
00:15:29
the whole
00:15:31
of what a concussion is or isn't is
00:15:34
subjective to an extent and not
00:15:37
everybody wants to pull them out when
00:15:39
they're feeling those symptoms or maybe
00:15:40
not everybody understands I kind of got
00:15:42
a little headache is that because I just
00:15:44
slept bad or is that because I just took
00:15:46
10 hits to the head right
00:15:49
pivoting a little bit you and talked
00:15:52
about a lot of experience with water
00:15:54
polo and I I know you you patent a
00:15:56
helmet at some point yeah earlier in
00:15:58
your career so I would like to hear
00:15:59
about that helmet in here too but I'm
00:16:02
curious about what you can tell me about
00:16:04
brain impacts and different kinds of
00:16:06
sports like football versus water polo
00:16:08
or LaCrosse or even soccer that we don't
00:16:11
necessarily wear helmets for but there's
00:16:13
definitely an impact to that situation
00:16:15
going on there yeah yeah so
00:16:18
um I will definitely start off by saying
00:16:20
every sport is different risk for
00:16:22
concussion and head impact exposure is
00:16:25
different for every sport it's even
00:16:27
different amongst different player
00:16:28
positions within the same sport so you
00:16:30
can't just say you know one approach or
00:16:33
one technology or one helmet is going to
00:16:35
solve concussion risk for every single
00:16:38
sport
00:16:39
um I guess I'll start by talking about
00:16:42
water polo my favorite sport uh so in
00:16:46
water polo just kind of going back to
00:16:49
the study that I was was a part of at UC
00:16:51
Irvine
00:16:52
what we were focused on was kind of
00:16:55
having that sport specific approach to
00:16:57
solving or kind of understanding the
00:17:00
head impact and concussion problem so
00:17:02
what we found by placing head impact
00:17:04
sensors on athletes as they went through
00:17:06
all their games and practices
00:17:08
we found that the frequency of the head
00:17:11
impacts the number of head impacts and
00:17:13
the type of impacts that players were
00:17:15
sustaining was largely dependent on the
00:17:18
position that a player played so for
00:17:20
example the centers in water polo who
00:17:23
are sitting right in front of the goal
00:17:24
usually accruing the most goals and
00:17:27
getting in the most physical
00:17:28
altercations with other players they
00:17:30
sustained the most impacts and those
00:17:33
types of impacts were impacts to the
00:17:35
back of the head so the player the
00:17:37
centers would be going for the ball and
00:17:38
their Defender would come up behind them
00:17:40
whether intentionally or not striking
00:17:42
them in the back of the head when we
00:17:44
publish those results there was a rule
00:17:46
change that came out shortly after that
00:17:48
more strictly penalized impacts from
00:17:51
behind so contact from behind a player
00:17:53
is now more strictly penalized so kind
00:17:55
of cool we saw that immediately lead to
00:17:58
a rule change that's kind of trying to
00:18:00
solve that head impact problem now when
00:18:03
it comes to concussions we found that
00:18:05
the centers were getting the most
00:18:07
impacts but they weren't getting the
00:18:08
most concussions it was the goalies who
00:18:10
got the most concussions
00:18:12
and it wasn't physical altercations with
00:18:14
other players causing the concussions it
00:18:16
was impacts from the ball so very very
00:18:20
different types of impacts very very
00:18:21
different types of uh consequences from
00:18:24
those impacts that we were seeing so
00:18:26
what we did was we evaluated some
00:18:29
existing protective headgears and we
00:18:30
also developed our own protective
00:18:32
headgear and then we tested them in the
00:18:34
lab with a crash test dummy to see how
00:18:37
effective those headgears were for those
00:18:39
bald ahead impacts
00:18:41
we found that they were pretty effective
00:18:43
rather than wearing just the normal
00:18:44
polyester cap that players wear today so
00:18:48
like the rule change with the centers we
00:18:51
also found that after publishing those
00:18:53
results there was a new rule change that
00:18:55
paved the way for allowing padded
00:18:58
protective headgears in the sport so
00:19:00
pretty cool there in soccer
00:19:03
no head gear is required we do see some
00:19:07
players wearing protective headbands or
00:19:09
soft shelled headgears
00:19:11
but really the main source of head
00:19:14
impacts in soccer is headers these
00:19:17
usually aren't going to lead to
00:19:18
concussions but it's that build up over
00:19:20
time of those repeated sub-concussive
00:19:23
impacts that has been linked to later
00:19:26
life risk of neurodegenerative diseases
00:19:28
and we've seen some studies like that in
00:19:30
soccer so or soccer specifically
00:19:33
what we tried to do in soccer because
00:19:35
wearing a headgear in soccer can really
00:19:37
change the Dynamics of the game when
00:19:40
you're doing all those headers we tried
00:19:42
to see if we could alter the inflation
00:19:43
pressure of the ball to see if that
00:19:45
would have any sort of impact and what
00:19:48
we found was that if you dipped ball
00:19:50
inflation pressure below the range
00:19:52
regulated by FIFA or the NCAA we could
00:19:55
get a pretty significant reduction in
00:19:57
the severity of those impacts now that
00:20:00
would be hard to translate to gameplay
00:20:02
of course because kicking a soft kind of
00:20:04
deflated ball around is going to be
00:20:05
different than one that's totally pumped
00:20:07
up but this could be something useful
00:20:09
for just getting kids into the right
00:20:12
training technique for headers or if you
00:20:13
just want to take a couple reps deflate
00:20:16
that all a little bit and it actually
00:20:17
could have a meaningful impact I want to
00:20:20
ask you about your experience with the
00:20:22
NSF funding and your graduate research
00:20:24
Fellowship
00:20:26
award what was that experience like for
00:20:29
you yeah so the application process is
00:20:32
rigorous you know it's it's a very It's
00:20:35
a Great Fellowship so it was a lot of
00:20:37
hard work
00:20:38
um but getting the fellowship has mostly
00:20:41
to me what it's meant to me has been
00:20:43
kind of the freedom to pursue my passion
00:20:46
for this field of research in a way that
00:20:49
um I really want to so I'm not locked
00:20:51
into a specific Grant or a specific
00:20:53
project that I'm not thrilled about but
00:20:55
I'm able to kind of take my research in
00:20:57
various different directions invent new
00:20:59
technologies work with different uh
00:21:01
populations
00:21:03
um yeah and then the NSF also has a
00:21:06
bunch of great professional development
00:21:07
opportunities that give you more than
00:21:10
just you know the typical graduate
00:21:12
school experience
00:21:15
what bit of research did you
00:21:17
specifically work on under that yeah so
00:21:21
for the uh grfp
00:21:25
um I've been working on the development
00:21:26
of the liquid shock absorbers yeah
00:21:29
I want to I want to kind of close out
00:21:31
thinking about your development and in
00:21:34
the in the paper you're mostly modeling
00:21:36
right it wasn't a physical specimen yep
00:21:39
so much so what is next steps there are
00:21:43
you have you built a prototype that's
00:21:46
physical what are you seeing with that
00:21:48
if you have already yeah yeah so we do
00:21:51
have some exciting results that we're
00:21:53
working on publishing right now where
00:21:55
we've kind of built out the uh physical
00:21:58
liquid shock absorbers and then
00:22:00
implemented them into a helmet I mean
00:22:03
we're seeing really good results so far
00:22:05
um obviously though when you design a
00:22:08
product there's more that goes into it
00:22:10
than just the safety performance so
00:22:14
we've got to work on things still with
00:22:16
industry collaborators like the comfort
00:22:18
and the Aesthetics and all that so
00:22:20
really there's
00:22:22
um a big translation ahead of making
00:22:25
this look like a really nice product
00:22:27
that people are going to know is more
00:22:29
than just a science project
00:22:31
cool yeah
00:22:33
um how are are you happy seeing the kind
00:22:37
of concept becoming the physical thing
00:22:40
it's the most satisfying thing ever yeah
00:22:43
especially when your model
00:22:46
um matches up with your experimental
00:22:47
results it's it's really satisfying and
00:22:50
it just gives you a lot of faith in the
00:22:51
whole scientific process that we're
00:22:53
going through to kind of make a big
00:22:55
impact in head protection
00:22:57
special thanks to Nicholas checky for
00:22:59
the discovery files I'm Nate potker
00:23:01
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00:23:08
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