Category Archives: Systems Theory

Linear Dynamics Application

There are a number of online apps that can show students the phase plane dynamics of a 2d system. Notable examples include: Phase Portrait Viewer from the d’Arbeloff Interactive Math Project – requires Java installed Wolfram Phase Portrait Viewer – … Continue reading

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Choke points, Load points, Hots spots and Key steps

Choke points, load points, hot spots, key steps and critical steps are some of the many phrases that have been coined to describe places in a biochemical network where perturbations are said to make a difference. Locating these places is … Continue reading

Posted in Enzyme Kinetics, General Science Interest, Metabolic Control Analysis, Modeling, Molecular Biology, Pathways, Systems Theory | Leave a comment

Irreversible Bistability

Last week I was in need of an irreversible bistable switch to show my class. I remember seeing one in the well known review by Tyson et al, Sniffers, buzzers, toggles and blinkers: dynamics of regulatory and signaling pathways in … Continue reading

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Michael Savageau’s Book in Print Again

I’ve been meaning to mention this for some time but Michael Savageau book, ‘Biochemical Systems Analysis’ is available in print again in the form of a paperback from amazon for only $29.95. I grew up with this book as an … Continue reading

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Building an Analog Integrator

Something I’ve been wanting to do for a while was is to build a simple analog integrator. Here is my first attempt. I bread-boarded the circuit first to get it working then made it more permanent and stable by soldering … Continue reading

Posted in Electronics, General Science Interest, Systems Theory | 1 Comment

Electronic Gene Circuit

The figure below shows a single unit from the Microryza gene network circuit project. The circuit models a transcription factor that acts as a repressor. The output from the circuit is the level of protein which can be fed into … Continue reading

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Misconceptions in Metabolism II

A week ago I wrote about some misconceptions in metabolism that arose from a trip to a systems biology workshop in Holland. This week I discovered that Nature is perpetrating similar misconceptions in their News and Views section. I came … Continue reading

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Misconceptions in Metabolism

I’m currently at the ISGSB meeting (International Study group for Systems Biology – formally BTK) in Holland. This is a group that values both theoretical analysis and experimentation in biochemical network analysis. Its an interesting group of people that I have literally … Continue reading

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Default Compartments in SBML

A reoccurring problem that I’ve had with SBML since day one is how to deal with a default compartment. Take for example a visual design tool such as JDesigner. At start up it creates an implicit compartment represented by the empty canvas. … Continue reading

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Ludicrous as it may sound

I was reminded the other day of an interesting quote from a 2000 FEBS paper which starts with: “How highly would one rate an economic analysis of a factory that ignored the consumer demand for its products? Ludicrous as it … Continue reading

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