<s>
SimThyr	B-Application
is	O
a	O
free	B-Application
continuous	O
dynamic	B-Application
simulation	I-Application
program	B-Application
for	O
the	O
pituitary-thyroid	O
feedback	O
control	O
system	O
.	O
</s>
<s>
The	O
open-source	B-Application
program	I-Application
is	O
based	O
on	O
a	O
nonlinear	O
model	O
of	O
thyroid	O
homeostasis	O
.	O
</s>
<s>
In	O
addition	O
to	O
simulations	O
in	O
the	O
time	O
domain	O
the	B-Application
software	I-Application
supports	O
various	O
methods	O
of	O
sensitivity	O
analysis	O
.	O
</s>
<s>
Its	O
simulation	B-Application
engine	O
is	O
multi-threaded	B-Operating_System
and	O
supports	O
multiple	O
processor	B-General_Concept
cores	I-General_Concept
.	O
</s>
<s>
SimThyr	B-Application
provides	O
a	O
GUI	B-Application
,	O
which	O
allows	O
for	O
visualising	B-Application
time	O
series	O
,	O
modifying	O
constant	O
structure	O
parameters	O
of	O
the	O
feedback	O
loop	O
(	O
e.g.	O
</s>
<s>
for	O
simulation	B-Application
of	O
certain	O
diseases	O
)	O
,	O
storing	O
parameter	O
sets	O
as	O
XML	B-Protocol
files	O
(	O
referred	O
to	O
as	O
"	O
scenarios	O
"	O
in	O
the	B-Application
software	I-Application
)	O
and	O
exporting	O
results	O
of	O
simulations	O
in	O
various	O
formats	O
that	O
are	O
suitable	O
for	O
statistical	O
software	B-Application
.	I-Application
</s>
<s>
SimThyr	B-Application
is	O
intended	O
for	O
both	O
educational	O
purposes	O
and	O
in-silico	O
research	O
.	O
</s>
<s>
Multiple	O
studies	O
have	O
employed	O
SimThyr	B-Application
for	O
in	O
silico	O
research	O
on	O
the	O
control	O
of	O
thyroid	O
function	O
.	O
</s>
<s>
Later	O
and	O
expanded	O
versions	O
of	O
the	B-Application
software	I-Application
were	O
used	O
to	O
develop	O
the	O
hypothesis	O
of	O
the	O
TSH-T3	O
shunt	O
in	O
the	O
hypothalamus-pituitary-thyroid	O
axis	O
,	O
to	O
assess	O
the	O
validity	O
of	O
calculated	O
parameters	O
of	O
thyroid	O
homeostasis	O
(	O
including	O
SPINA-GT	O
and	O
SPINA-GD	O
)	O
and	O
to	O
study	O
allostatic	O
mechanisms	O
leading	O
to	O
non-thyroidal	O
illness	O
syndrome	O
.	O
</s>
<s>
SimThyr	B-Application
was	O
also	O
used	O
to	O
show	O
that	O
the	O
release	O
rate	O
of	O
thyrotropin	O
is	O
controlled	O
by	O
multiple	O
factors	O
other	O
than	O
T4	O
and	O
that	O
the	O
relation	O
between	O
free	B-Application
T4	O
and	O
TSH	O
may	O
be	O
different	O
in	O
euthyroidism	O
,	O
hypothyroidism	O
and	O
thyrotoxicosis	O
.	O
</s>
<s>
SimThyr	B-Application
is	O
free	B-Application
and	O
open-source	B-Application
software	I-Application
.	O
</s>
<s>
This	O
ensures	O
the	O
source	O
code	O
to	O
be	O
available	O
,	O
which	O
facilitates	O
scientific	B-Application
discussion	O
and	O
reviewing	O
of	O
the	O
underlying	O
model	O
.	O
</s>
<s>
The	B-Application
software	I-Application
provides	O
an	O
editor	O
that	O
enables	O
users	O
to	O
modify	O
most	O
structure	O
parameters	O
of	O
the	O
information	O
processing	O
structure	O
.	O
</s>
<s>
This	O
functionality	O
fosters	O
simulation	B-Application
of	O
several	O
functional	O
diseases	O
of	O
the	O
thyroid	O
and	O
the	O
pituitary	O
gland	O
.	O
</s>
<s>
Parameter	O
sets	O
may	O
be	O
stored	O
as	O
MIRIAM	O
-	O
and	O
MIASE-compliant	O
XML	B-Protocol
files	O
.	O
</s>
