Click on parameter names to see sources of
reference and derivations of values (where applicable).
Name
| Description
| Value
| Units
|
initial astrocyte count
| Number of astrocyte agents in the simulation.
| 100
|
|
activation level
| Concentration of IL-1B (at same site as astrocyte)
that activates astrocytes to begin absorbing IL-1B.
| 0.1
| nM
|
maximum density
| Maximum density of cells at site that prevent astrocytes from
invading that site.
| 3
|
|
number of cells per agent
| Number of astrocyte cells represented by an astrocyte agent.
| 10.0
|
|
IL-1B threshold for motility
| Concentration of absorbed IL-1B that allows an astrocyte to move.
| 10.0
| nM
|
maximum speed
| Maximum speed at which astrocytes can move.
| 1.0
| micron/min
|
probability of moving towards stimulus
| Probability that an astrocyte will move towards fibrous amyloid
when fibrous amyloid is sensed and the astrocyte is motile.
| 0.9
|
|
probability of blocking
| The probability for each astrocyte represented by an agent to
participate in blocking.
| 0.5
|
|
reduction percentage for diffusivities
| The percent at which the diffusivity of chemicals is reduced
due to every blocking astrocyte.
| 0.15
|
|
IL-1B receptor equilibrium constant
| Ratio of the IL-1B receptor unbinding rate to binding rate.
| 1.0
| nM
|
IL-1B receptor binding rate
| Rate at which IL-1B binds to an IL-1B receptor.
| 0.01
| nM-1min-1
|
IL-1B receptors per astrocyte
| Number of IL-1B receptors per astrocyte.
| 2000.0
|
|
IL-1B receptor conversion rate
| The rate at which a bound IL-1B receptor becomes internalized
or triggers a corresponding signal.
| 60.0
| min-1
|
fraction of bound IL-1B rec triggering IL-6
| The fraction of IL-1B receptors that need to be bound in order
to trigger the release of IL-16.
| 0.001
|
|
fraction of bound IL-1B rec triggering TNF
| The fraction of IL-1B receptors that need to be bound in order
to trigger the release of IL-16.
| 0.001
|
|
typical cell duration
| The active life span of an astrocyte. (Not used in simulation.)
| 300.0
| min
|
Name
| Description
| Value
| Units
|
initial microglia count
| Number of microglia agents representing multiple microglial cells
in region initially.
| 40
|
|
maximum density
| Maximum number of microglial agents allowed to occupy one grid space
in the simulation.
| 3
|
|
number of cells per agent
| The number of microglia represented by one microglial agent.
| 10.0
|
|
maximum speed
| The speed at which microglia move. Used in simulation to determine
how many time steps to delay before moving.
| 1.5
| micron/min
|
chemotactic sensitivity
| Probability that microglia will move up
a gradient of soluble amyloid protein.
| 0.67
|
|
half-sticking fiber level
| Concentration of fibrillar amyloid protein at which half the microglia
would stick (i.e at which the probability of sticking is 50%).
| 50.0
| nM
|
half-sticking sAB level
| Concentration of soluble amyloid that reduces fraction of adhering
microglia by 50%.
| 20000.0
| nM
|
maximum sAB microglia uptake rate
| Maximum rate of uptake of soluble amyloid protein by microglia.
| 0.1
| nM/min
|
half max amyloid binding concentration
| Concentration of soluble amyloid protein at which half of the
maximal binding rate occurs.
| 15.0
| nM
|
chemical breakdown
| Rate of degradation of amyloid by microglia.
| 0.01
| min-1
|
Cell Death
| Can be turned on to assume cells dying or stopping their activity.
| Off
|
|
max sol-AB capacity
| Maximum amount of amyloid that a microglia cell can hold.
| 1.0
| nM
|
typical cell duration
| Average time it takes for microglia to die or cease activity.
| 300.0
| min
|
Cell Mitosis
| Can be turned on to assume birth of new microglia or recruitment
of more microglia.
| Off
|
|
legnth of cell cycle
| The time period between mitosis.
| 60.0
| min
|
poison effects on mitosis
| The fraction of the maximum amyloid absorption that causes
mitosis not to occur.
| 0.5
|
|
chance of mitosis
| If all other mitosis conditions are satisfied, this gives the
odds that mitosis actually occurs.
| 0.9
|
|
Name
| Description
| Value
| Units
|
IL-1B receptor equilibrium constant
| Ratio of the neuron IL-1B receptor-ligand unbinding rate
to binding rate.
| 1.0
| nM
|
IL1B receptor binding rate
| Rate at which IL-1B binds to receptors.
| 0.01
| nM-1 min-1
|
IL-1B receptors per neuron
| Number of IL-1B receptors per neuron.
| 2000.0
|
|
IL-1B receptor conversion rate
| The rate at which bound IL-1B receptors get internalized
and signal activity within the neuron.
| 60.0
| min-1
|
source triggering level
| Level of IL-1B in neurons that cause neuron to become a
new source of soluble amyloid.
| 100.0
| nM
|
maximum proportion of sources
| The probability that a neuron will become an amyloid
source once the triggering level is reached.
| 0.01
|
|
maximum IL-1B absorbed
| The maximum amount of IL-1B that a neuron will absorb
(also determines the level at which neurons secrete the
maximum amount of amyloid).
| 200.0
| nM
|
IL-6 receptor equilibrium constant
| Ratio of the neuron IL-6 receptor-ligand unbinding rate to
binding rate.
| 4.32
| nM
|
IL-6 receptor binding rate
| Rate at which IL-6 binds to receptors on neuron.
| 0.01
| nM-1 min-1
|
IL-6 receptors per neuron
| Number of IL-6 receptors per neuron.
| 500.0
|
|
IL-6 receptor conversion rate
| The rate at which bound IL-6 receptors get internalized
and signal activity within the neuron.
| 60.0
| min-1
|
maximum IL-6 absorbed
| Maximum amount of IL-6 absorbed by a neuron.
| 50.0
| nM
|
TNF receptor equilibrium constant
| Ratio of the neuron TNF receptor-ligand unbinding rate
to binding rate.
| 1.3
| nM
|
TNF receptor binding rate
| Rate at which TNF binds to receptors on neuron.
| 0.01
| nM-1 min-1
|
TNF receptors per neuron
| Number of TNF receptors on a neuron.
| 1100.0
|
|
TNF receptor conversion rate
| The rate at which bound TNF receptors get internalized
and signal activity within the neuron.
| 60.0
| min-1
|
maximum TNF absorbed
| Maximum concentration of TNF in neuron.
| 100.0
| nM
|
amyloid conc affecting health
| A scaling factor for determining how soluble
amyloid affects health.
| 200.0
| nM
|
fiber conc affecting health
| A scaling factor for determing how fibrous
amyloid affects health.
| 50.0
| nM
|
IL-1B effects on health
| A factor used to determine how IL-1B affects the health of a neuron
(negative values mean that IL-1B is detrimental to neuron health,
positive values mean that IL-1B is beneficial to neuron health and
a value equal to zero means that IL-1B has no effect).
| 0.0
|
|
IL-6 effects on health
| A factor used to determine how IL-6 affects the health of a neuron
(negative values mean that IL-6 is detrimental to neuron health,
positive values mean that IL-6 is beneficial to neuron health and
a value equal to zero means that IL-6 has no effect).
| -10.0
|
|
TNF effects on health
| A factor used to determine how TNF affects the health of a neuron
(negative values mean that TNF is detrimental to neuron health,
positive values mean that TNF is beneficial to neuron health and
a value equal to zero means that TNF has no effect).
| 1.0
|
|
amyloid effects on health
| A factor used to determine how soluble amyloid affects the health of a neuron
(negative values mean that amyloid is detrimental to neuron health,
positive values mean that amyloid is beneficial to neuron health and
a value equal to zero means that amyloid has no effect).
| 0.0
|
|
fiber effects on health
| A factor used to determine how fibers affect the health of a neuron
(negative values mean that fibers are detrimental to neuron health,
positive values mean that fibers are beneficial to neuron health and
a value equal to zero means that fibers have no effect).
| -0.1
|
|
health recovery rate
| Rate at which a neuron recovers from detrimental effects.
| 0.1
| min-1
|
threshold of no recovery
| The health value below which simple neuron recovery is
ineffective.
| 0.05
|
|