Biomedical and Biotechnology,
A. Rafie Lak; O. Vahidi
Volume 15, Issue 3 , September 2018, , Pages 34-52
Abstract
This paper presents using the fractional PImDn controller module which manipulates insulin infusion rate to maintain normoglycemia in subjects with type 1 diabetes. To prevent severe hypoglycemia, a conventional proportional controller is used to regulate glucagon infusion rate when the blood glucose ...
Read More
This paper presents using the fractional PImDn controller module which manipulates insulin infusion rate to maintain normoglycemia in subjects with type 1 diabetes. To prevent severe hypoglycemia, a conventional proportional controller is used to regulate glucagon infusion rate when the blood glucose levels fall below a threshold. Two sets of controller parameters are obtained and evaluated. For the first tuning set, clinical data from an oral glucose tolerance test taken from a group of healthy subjects are used to obtain the controller parameters such that it can mimic a real healthy pancreas. To obtain the second tuning set, the controller parameters are optimized through a sequential quadratic programming algorithm. Using the second tuning set, the in silico 2-hour postprandial test result and comparing it with the glucose concentration trajectory of the healthy subjects show that the controller performs well in returning the blood sugar levels into the glucose homeostasis while keeping the plasma insulin concentration within the acceptable physiological range. It is indicated that the manipulation of glucagon infusion rate is effective in hypoglycemia prevention if more aggressive controller settings are chosen or dysfunctional insulin infusion occurs.
Biomedical and Biotechnology,
M. Saeedi; O. Vahidi
Volume 14, Issue 4 , December 2017, , Pages 59-79
Abstract
In this paper, we simulate magnetic hyperthermia process on a mathematical phantom model representing cancer tumor and its surrounding healthy tissues. The temperature distribution throughout the phantom model is obtained by solving the bio-heat equations and the consequent cell death amount is calculated ...
Read More
In this paper, we simulate magnetic hyperthermia process on a mathematical phantom model representing cancer tumor and its surrounding healthy tissues. The temperature distribution throughout the phantom model is obtained by solving the bio-heat equations and the consequent cell death amount is calculated using correlations between the tissue local temperature and the cell death rate. To have an estimate of heat generated from typical magnetic nanoparticles, magnetite nanoparticles are synthesized and the heat dissipation amount from the synthesized nanoparticles exposed to an alternating magnetic field is measured and used in the computer simulation. The impact of the amount of heat generated from the magnetic nanoparticles exposed to an alternating magnetic field, their distribution patterns in the tumor and hyperthermia process duration time on the cell death rate in both cancer and healthy tissues are investigated. It is indicated that while various factors contributing in the heat dissipation amount from the magnetic nanoparticles are important in the effectiveness of the magnetic hyperthermia process, the distribution pattern plays the major role in determining the efficiency of the process.