ABSTRACT
Because of increasing risk of diabetes, the measurement along with control of blood sugar has been of great importance in recent decades. In type I diabetes, because of the lack of insulin secretion, the cells cannot absorb glucose leading to low level of glucose. To control blood glucose (BG), the insulin must be injected to the body. This paper proposes a method for BG level regulation in type I diabetes. The control strategy is based on nonlinear model predictive control. The aim of the proposed controller optimized with genetics algorithms is to measure BG level each time and predict it for the next time interval. This merit causes a less amount of control effort, which is the rate of insulin delivered to the patient body. Consequently, this method can decrease the risk of hypoglycemia, a lethal phenomenon in regulating BG level in diabetes caused by a low BG level. Two delay differential equation models, namely Wang model and Enhanced Wang model, are applied as controller model and plant, respectively. The simulation results exhibit an acceptable performance of the proposed controller in meal disturbance rejection and robustness against parameter changes. As a result, if the nutrition of the person decreases instantly, the hypoglycemia will not happen. Furthermore, comparing this method with other works, it was shown that the new method outperforms previous studies.
ABSTRACT
OBJECTIVE: The purpose of this study was to determine mean maximum bite force in adults with normal occlusion and to evaluate effect of face form on it. DESIGN: Twenty male and 20 female students with normal dentitions and between the ages of 19 and 27 participated in the study. A strain-gauge force transducer was developed to measure bite force and was calibrated with known loads. Three measurements were performed on each side of the dentition in the first molar region and mean values used for analysis. Face form was defined as square, tapering, square-tapering or oval and determined using digital photographs. Effect of gender and face form on bite force was statistically analysed using two-way ANOVA and Duncan tests. RESULTS: Mean maximum bite force and standard deviation (S.D.) in the sample population was 64.4 (24.0) kilograms (kg). In men, the mean was 73.6 (23.8) which was statistically higher than in women (53.0 (19.6) kg) (P < 0.05). Mean maximum bite force in subjects with square face form was 93.7 kg, which was significantly higher than in subjects with other facial forms (P < 0.05). CONCLUSION: The results showed higher bite force in men and those with square face form. Square face form may contribute to higher bite force values by maintaining a higher mechanical advantage for muscles of mastication.
