Chaste  Release::3.4
Kerchoffs2003ContractionModel.cpp
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36 
37 #include "Kerchoffs2003ContractionModel.hpp"
38 #include "Exception.hpp"
39 #include "TimeStepper.hpp"
40 #include <iostream>
41 
42 const double Kerchoffs2003ContractionModel::a6 = 2.0; // 1/um
43 const double Kerchoffs2003ContractionModel::a7 = 1.5; // um
44 const double Kerchoffs2003ContractionModel::T0 = 180; // kPa
45 const double Kerchoffs2003ContractionModel::Ea = 20; // 1/um
46 const double Kerchoffs2003ContractionModel::v0 = 0.0075; // um/ms
47 const double Kerchoffs2003ContractionModel::ls0 = 1.9; // um
48 const double Kerchoffs2003ContractionModel::ld = -0.4; // um
51 
54 {
56 
58 
59  mStateVariables.push_back(mSarcomereLength-1.0/Ea); //steady state
60 
61  mIsActivated = false;
63  mActivationTime = 0.0;
64  mTime = 0.0;
65 
66  this->mParameters.resize(3);
67  SetParameter("tr", 75.0); // ms
68  SetParameter("td", 75.0); // ms
69  SetParameter("b", 150.0); // ms/um
70 }
71 
72 
74  const std::vector<double>& rY,
75  std::vector<double>& rDY)
76 {
77  double lc = rY[0];
78  rDY[0]=( Ea*(mSarcomereLength-lc) - 1 )*v0;
79 }
80 
81 
83 {
84  assert(rInputParameters.voltage != DOUBLE_UNSET);
85 
86  if (mIsActivated && (rInputParameters.voltage < mDeactivationVoltage))
87  {
88  // inactive (resting) - note don't set mIsActivated=false yet
89  // as the cell may yet be producing force, and the code is such
90  // that if mIsActivated=false, Ta=0
92  }
93 
94  if (!mIsActivated && (rInputParameters.voltage > mActivationVoltage))
95  {
96  // activated
97  mIsActivated = true;
100  }
101 }
102 
103 void Kerchoffs2003ContractionModel::SetStretchAndStretchRate(double stretch, double stretchRate)
104 {
105  mSarcomereLength = stretch*ls0;
106 }
107 
108 
110 {
111  double f_iso = 0;
112  if(lc > a7)
113  {
114  f_iso = T0 * pow(tanh(a6*(lc-a7)),2);
115  }
116 
117  double f_twitch = 0;
118  double b = this->GetParameter("b");
119  double t_max = b*(mSarcomereLength - ld);
120  if(mIsActivated)
121  {
122  double t_a = mTime - mActivationTime;
123 
124  if(t_a < t_max)
125  {
126  double tr = this->GetParameter("tr");
127  double td = this->GetParameter("td");
128  f_twitch = pow( tanh(t_a/tr)*tanh((t_max-t_a)/td), 2);
129  }
130  else if(mElectricallyUnactivated)
131  {
132  // t_a < t_ma => f_twitch=0 => Ta=0
133  // In this case, if electrically unactivated as well,
134  // set the state to be unactivated.
135  mIsActivated = false;
136  }
137  }
138 
139  // expl is unstable for dt = 0.01, 0.001, impl is fine
140  return (mSarcomereLength/ls0)*f_iso*f_twitch*(mSarcomereLength-lc)*Ea;
141 }
142 
143 
145 {
147 }
148 
150 {
152 }
153 
154 template<>
156 {
157  this->mVariableNames.push_back("lc");
158  this->mVariableUnits.push_back("um");
159 
160  this->mParameterNames.push_back("tr");
161  this->mParameterUnits.push_back("ms");
162  this->mParameterNames.push_back("td");
163  this->mParameterUnits.push_back("ms");
164  this->mParameterNames.push_back("b");
165  this->mParameterUnits.push_back("ms/um");
166 
167  this->mInitialised = true;
168 }
static boost::shared_ptr< OdeSystemInformation< ODE_SYSTEM > > Instance()
void SetStretchAndStretchRate(double stretch, double stretchRate)
const double DOUBLE_UNSET
Definition: Exception.hpp:56
void SetParameter(const std::string &rName, double value)
void EvaluateYDerivatives(double time, const std::vector< double > &rY, std::vector< double > &rDY)
boost::shared_ptr< AbstractOdeSystemInformation > mpSystemInfo
void SetInputParameters(ContractionModelInputParameters &rInputParameters)