Fluxion

What's New

Crash reporting system integrated to monitor and report application crashes in real-time.
Realistic mitochondrial membrane potential and matrix pH. The inner-membrane potential now sits in the physiological 150-190 mV range and falls as the cell works harder, rather than reading around 230 mV and climbing under load, and the matrix correctly runs about half a pH unit more alkaline than its surroundings. The guided Oxygen Supply exercise is far more accurate as a result.
A working aerobic-to-anaerobic switch, driven by a new glycerol-3-phosphate shuttle. As oxygen is withdrawn the cell now spends phosphocreatine first, then floods with lactate as anaerobic glycolysis takes over and defends ATP -- the exact sequence the Oxygen Supply exercise is meant to teach, which the model previously could not sustain.

ROS balance and buffer split
Matrix malate and the other citric-acid-cycle intermediates now hold at physiological levels during sustained exercise instead of slowly accumulating over several minutes.
A realistic resting cell. The default resting simulation now runs at a physiological resting metabolic rate, with the membrane potential settling near 180 mV, instead of the previous near-zero "idling" state that pushed the potential unnaturally high and left the resting readouts unphysiological.
Stable resting phosphate. Cytosolic free phosphate now holds a steady, realistic resting level of about 1 mM and rises during exercise as phosphocreatine is spent, instead of being stripped toward zero. A phosphate-homeostasis process now keeps it in balance, standing in for the cell's phosphate transport and regulation.
A realistically oxidised resting matrix. At rest the mitochondrial matrix now holds a physiological oxidised balance (NAD+/NADH around 5) instead of reading almost fully reduced. Real mitochondria never sit exactly at their maximum driving force, even at rest; the model now captures that with a small "respiratory slip" — a finite-coupling pathway that carries a few electrons to oxygen while pumping fewer charges — so the chain runs just below its ceiling and both the matrix balance and the membrane potential land in their measured ranges.

Long simulations of hard exercise or low oxygen no longer collapse to zero ATP after a few minutes; they now stay stable for a full simulated hour.

The respiratory slip that oxidises the resting matrix is modelled as a single lumped pathway, which leaves a few small artefacts: the membrane potential dips slightly at the very lowest workloads before falling as work increases, the resting cell takes a little longer to settle to a perfectly steady state, and oxidative metabolism runs a touch less efficient than the textbook oxygen-to-ATP ratio. Smoothing these needs a deeper rework that lets the chain's coupling vary continuously with the driving force, which is planned.
During prolonged oxygen-free work the modelled cell drifts slightly alkaline instead of acidifying, because exported lactate carries its acid out to the blood pool, which is not modelled as buffered.

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