The Systems Biology of COVID-19 and the SARS-CoV-2 virus. The class will build a foundation that includes the emergence of complexity, simple biological subsystems, their reductionist and equivalent toy and organ-chip models, and the measurements required to specify model architecture and parameters. Applications to biology, physiology, medicine, chemical and biological defense, pharmacology, drug discovery, and toxicology. UGrad: PHYS 240 01 and BME 290B; Grad: PHYS 326 and BME 395C.
0) Knew: I've seen simplified control models such as the Hodgkin-Huxley model of neurons and blood-glucose control by insulin.
ReplyDelete1) Learned: Categorizing systems as controllable, observable, stabilizable, and detectable is important to scope control systems
2) Question: When is open-loop control a "good enough" approximation for a model? I assume closed-loop control will be a stretch for the complex MGLBA in vitro system.
3) Presentation: Breakdown of controllability, observability, stabilizability, detectability of control loops IN and OF MGLBA. What can be controlled with open- and closed-loop systems?
4) Thoughts: This presentation had some good examples and provided a summary of the attributes of systems that lend themselves to outside control loops.
0) Knew: I have previously learned about many of the simplified versions of control feedback mechanisms such as thermoregulation, blood clotting, and neuromuscular control.
ReplyDelete1) Learned: I learned about the simplified Hodgkin-Huxley model, and how to examine an action potential through control. When sodium ions enter the axoplasm, they depolarize the cell with positive feedback. When potassium ions leave the axoplasm, they depolarize the cell through negative feedback. It was interesting that in this model Chlorine ions were ignored.
2)Question:
To what degree does the dynamic GBLA meet the conditions of being controllable, observable, stabilizable, and detectable?
3) Presentation:
Opening the Feedback Loop and diagramming control in the Gut-Liver-Pancreas-Stomach loop.
4)Thoughts:
This presentation provided a good overview of control, and also the key aspects to consider in a dynamic process (controllability, observability, stabilizability, and detectability). It may be helpful to build a list of the various examples of control at different scales within the GBLA.
0: Controllability, Observability, closed-loop/open-loop control
ReplyDelete1: I vaguely remember the definitions of stabilizable and detectable but it was good to reread them.
2: The role of the u and y vector is clear in the figure but the meaning of the x and w are more subtle. It should be noted that they apply to all cases in the figure and they may or may not be measurable. Also the system state, x, can be dependent on x,u,w.
3: Unstable processes in the GLBA.
4: These are good definitions to know and the idea of looking out for unstable processes will be crucial.
0) What I Already Knew:
ReplyDeleteBasic control theory. Closed vs. open loops. Positive and negative feedback.
1) What I Learned:
The Hodgin-Huxley Model. It may be possible that I have seen this before, but modeling neurons with circuits is fascinating. Control systems exhibit oscillations with excess delay or gain. These oscillations may be very fast yet vital to biological systems and need to be further studied. Systems need to be both controllable and observable to apply closed-loop control.
2) Questions:
What parts of the GBLA could be faked with circuitry? How do we readily know which portions of the axis are controllable? Can we reduce certain elements into familiar control systems?
3) Class Presentation:
High-speed measurements and sensors.
4) Thoughts:
Slightly more technical approach to control. But good to see more examples in biology.
0) What I already knew
ReplyDeleteI was familiar with most of the control theory concepts from what we discussed in class and from my systems physiology class, where we studied the body as a circuit and voltage clamp experiments.
1) What I learned
Terminology: Controllable, Observable, Stabilizable, Detectable systems. A system is completely controllable if there is a control history in a finite time interval. A system is observable if there is adequate output history to construct the input. A system is stabilizable if an uncontrolled subprocess in a controllable process is stable. A system is detectable if the unobserved sub process is stable.
2) Most pressing questions
Is our GBLA controllable, observable, stabilizable, and detectable? I don’t think it’s controllable. I think it is observable, stabilizable, and detectable.
3) Presentation topic
Gut brain axis in the context of control theory. Analyzing if it is gray box, black box, control or open loop, controllable or not.
4) Thoughts
Very clear concise overview of control