List of aging-relevant bionumbers/basic units #FirstPrinciples

#22

FIGURE 1

Open in figure viewerPowerPoint

Estimation of cell-specific plasma EV to cell ratio. (a) In healthy humans, plasma EVs are mainly derived from blood cells, and ∼41% is derived from the adaptive immune system cells (B, CD4, and CD8 cells), ∼23% from the innate immune system cells (monocytes, NK cells, and neutrophils), and ∼35% from non-immune blood cells (erythrocytes and platelets). The remaining <1% is derived from cells in solid organs. A more resolved distribution map is shown in Figure S1a. The relative abundances are shown in parentheses. (b) The total number of parental blood cells and their plasma EVs. The overall plasma EV/cell ratio is ∼2. Error bar represents the estimate’s standard deviation. (c) Plasma EV number versus cell abundance for human blood cell types. A graph with more resolved values for CD8 memory cells is shown in Figure S2a. Error bar represents the estimate’s standard deviation.

https://isevjournals.onlinelibrary.wiley.com/doi/full/10.1002/jex2.46

there are 10 trillion cells. getting an infusion of 10 billion exosomes is nothing…

#23
#24

https://x.com/JuliaEckert10

#25

Scaling:

Below that critical point, the replication time is dominated by molecular collisions and hence by diffusion. Accordingly, the characteristic times should scale at least as t~ L^2 – slope 2 on the log-log plot. In fact, the slope is even higher, t~L^4…5: a 20-nm ribosome grabs tRNA in milliseconds; a 1-μm protocell takes minutes. This is the sluggish, random world of chemistry— life’s raw ingredients senselessly searching for each other by Brownian motion.

On large scales, above 1 μm, the slope flattens to t~L or so. This resonates with Geoffrey West’s scaling model, suggesting that in living systems metabolic rate scales as B~M^3/4, thanks to optimized networks—capillaries, cytoplasm flows. The replication time becomes the development time, which is t~m^1/4 and L^3/4, which 3/4 being close to the observed 1. That’s manifestation of life’s superpower: directing matter and energy flows, not just relying on random collisions.

At the critical point, chemistry becomes biology. That kink at 1 μm, 1,000 s—it’s where diffusion hands off to directed flows. A bacterium-sized cell is thus the smallest “machine” that can self-replicate with metabolism, not just diffusion.

G. West argues the L^3/4 scaling comes from evolutionary optimization—natural selection tweaking networks for efficiency. So, this critical point might be when evolution kicks in, turning a replicator into life: an optimization process driven by natural selection.

Phillips also has youtube videos of physical cell biology