Follow Slashdot stories on Twitter

 



Forgot your password?
typodupeerror
×

Comment Head Tracking (Score 1) 100

Head tracking may work well, depending on ability to control head/neck. There are several methods (mostly originating in the flight sim community).

1. Face tracking (very easy to try, FaceTrackNoIR or Opentrack)
2. Head tracking with IR clip (bit more reliable than face, many DIY guides out there)
3. Head tracking with Aruco marker (available in Opentrack)

Comment Re:Electron transport in biological systems (Score 1) 188

Are there any existing models of electron transport in biological systems?

Good question! The answer is yes, although they are not even mentioned in this unreviewed manuscript (which seems like hokum to me). Electron transfer in proteins is particularly well understood in the context of Marcus theory. The wiki article isn't great, but it has some good information and further references. A key insight is the "inverted driving force effect," an experimentally validated prediction of Marcus theory that electron transfer rates actually start to decrease if the transfer reaction is too exergonic (energetically favored).

Without going into a ton of detail, quantum effects are actually quite important for electron transfer, and some enzymes even encourage tunneling, mostly of electrons, as part of catalysis. Considering that the de Broglie wavelength of a 10 kJ electron is about 18 angstroms (biologically relevant scales), it's not really that surprising. Frequently, there are favored tunneling pathways through enzymes which electrons tend to follow.

Enzymes also sometimes utilize nuclear tunneling (i.e. tunneling proton/hydrogen/hydride), which is really, really cool. I am a fan of this paper which shows how tunneling is is encouraged through dynamic gating motions in a enzyme on the chlorophyll production pathway.

Comment Re:Assuming a grand meaning seems to be overreachi (Score 1) 188

As a current biochemist, I do wonder why the paper doesn't even mention Marcus theory or other previous work in enzymatic charge transfers. There really are some sweet quantum effects in biology, like enzyme-catalyzed proton tunneling, but I think the unreviewed manuscript under discussion here is hokum.

Comment Re:quantum tunneling? (Score 1) 188

Tunneling (mostly of electrons) is actually widespread in proteins, and its not hard to see why that is when you consider that the de Broglie wavelength of a 10 kJ electron is around 18 angstroms (these are relevant energy/distance scales in enzymes). Search "Marcus theory" for more information...

What's really cool is that some enzymes actually boost tunneling probabilities (e.g. through particular short-timescale motions) as an essential component of catalysis. In some cases, tunneling even occurs for larger particles like protons/hydrogens/hydrides. I really like this paper, for example, which shows how proton tunneling is essential in a light-activated enzyme involved in an early stage of chlorophyll synthesis in some plants.

Unfortunately, the unreviewed manuscript from TFA seems like nonsense to this biochemist. It doesn't seem to line up with, or even reference, any of the five decades of existing science in the area.

Comment Re:Complexity is not a property of the observer (Score 1) 188

biological systems, even at the single protein level, are doing things with electron conductance that can't be done in non-biological systems.

There really are some very cool quantum effects in biomolecules, for example enzymes which take catalyze electron tunneling and even proton tunneling. Electron transfer in proteins in particular is actually pretty well understood via Marcus theory. There is extensive theoretical and experimental work going back five decades in this area - all of which is totally ignored by the unreviewed manuscript under discussion.

biomolecules belong to an entirely new class of conductor that is not bound by the ordinary rules of electron transport

Unfortunately, your post and TFA alike do not appropriately distinguish between wildly different classes of "biomolecules."

Comment Re:Perspective from a chemist (Score 2) 188

I'm just a layman, but to my untrained eye this looks like word salad.

I'm a biochemist specializing in molecular biophysics, and I agree.

It's not always true, but as a general rule of thumb that some throwing "quantum" into a biology discussion is usually talking crap.

Definitely not always - there are actually enzymes which take advantage of electron tunneling, and even proton tunneling, for catalysis. Here's a particularly cool paper (no paywall) about a light-activated oxidoreductase which encourages a proton to tunnel.

Comment Re:Perspective from a chemist (Score 1) 188

There is no reference to existing models of electron transport in biological systems

I was struck by the same observation. It also seems like the authors are unaware of the newish linear-time DFT codes.

In case anyone has some knowledge of quantum mechanics and biology, and is interested in electron transfer in biomolecules, Wikipedia has an article on Marcus theory that is an OK place to start. Not the best article, but it discusses the inverted driving force effect and has references to follow up.

Comment Re:Sell any stock before they launch this... (Score 1) 375

any religion can simply claim it was created that way or the supernatural will of some supernatural being and you have absolutely no way to factually test or refute that.

In principle, religions can make only nonfalsifiable claims, yes. However, all extant religions in fact make significant falsifiable claims.

I have never heard a Christian claim they believe only that their God created an inflationary spacetime and nothing else.

Comment Re:Bombs? (Score 1) 533

You are confusing money - liquid institutional financial liabilities - with real resources. The United States can never run out of US dollars. It can run out of real resources. You have to make the case that the US is in danger of running out of food, metal or human capital, since it can never run out of a financial asset of which it is sole issuer.

Slashdot Top Deals

Understanding is always the understanding of a smaller problem in relation to a bigger problem. -- P.D. Ouspensky

Working...