Viscoelastic and Viscoplastic Glucose Theory (VGT #2): Applying the Concept of Viscoelasticity and Viscoplasticity to Conduct a “Time-Dependent Glucose Analogy” Study of An Elastic Glucose Case Covering 4,056 meals <180 mg/ dL Versus Plastic Glucose Case of 23 Meals >180 mg/dL Using Collected Postprandial Plasma Glucose Data from 4,079 Meals over 3.7-Year Period from 5/8/2018 to 1/10/2022 Based on GH-Method:

Abstract

The author has studied strength of materials and theory of elasticity through his undergraduate courses at the University of Iowa. He also conducted research work to earn a master’s degree in Biomechanics under Professor James Andrews. He remembers using the spring and dashpot models to simulate the behaviors of human joints, bones, muscles, and tendons to investigate the human-weapon interactions. Later, he went to MIT to pursue his PhD study under Professor Norman Jones, who taught him theory of plasticity and dynamic plastic behaviors of structure elements, and took additional graduate courses in the field of fluid dynamics and thermodynamics. Since then, many advancements have been made in biomechanics in a few application areas, especially tissues of the human body which possess viscoelastic characteristics, such as bone, muscle, cartilage, tendon (connect bone to muscle), ligament (connect bone to bone), fascia, and skin. For example, the night splint dorsiflexes forefoot at the back of the foot increases plantar fascia tension to offer stress-relaxation for plantar fascia pain. This model of muscles and tendons connecting the lower leg and foot is a type of viscoelastic problem. However, when dealing with the human internal organs, it is not easy to conduct live experiments to obtain accurate measurements of material properties. Although blood itself is a viscous material, the viscosity factor may fall between water, honey, syrup, or gel. However, the author’s research subject is “glucose”, the sugar amount in blood carried by cells, not the blood itself. It is nearly impossible to measure material geometry or certain engineering properties of glucose, for example, the viscosity of “glucose”. Therefore, the best he could do is to apply the “concept of viscoelasticity and/or viscoplasticity” to construct an analogy model of time-dependent glucose behaviors. The author’s background includes mathematics, physics, and various engineering disciplines, not including biology and chemistry. As a result, he can only investigate the observed biomedical phenomena using his ready-learned math-physical tools. He has already conducted some investigations of glucose behaviors using elasticity theory and plasticity theory and written a few articles from his findings. In the elasticity and plasticity papers, he utilized the postprandial plasma glucose (PPG) value as the strain along with carbs/sugar amount and post-meal exercise level as the stress. In a recent email from Professor Norman Jones, he said that: “I have wondered if the use of viscoelastic/viscoplastic materials might be of some value to your studies. These phenomena embrace time-dependent behaviour and I know that you have emphasized the time-dependence of various behaviours in the body. Just a thought.” His suggestion triggered the author’s interest and desire to research the subject of glucose behaviors further using viscosity theory. This particular article is a follow-up to his paper No. 578 which studies certain generic characteristics of viscoelastic glucose behaviors. In this paper, he uses a relative glucose level (individual PPG - average PPG) as the strain and the strain rate (dε/dt) multiplied with