Mapping A Fruit Fly’s Brain With Crowdsourced Research

October 15, 2024 by Maya Posch 13 Comments

Example of a graph representation of one identified network with connections coded by neurotransmitter types. (Credit: Amy Sterling, Murthy and Seung Labs, Princeton University)

Compared to the human brain, a fruit fly (Drosophila melanogaster) brain is positively miniscule, not only in sheer volume, but also with a mere 140,000 or so neurons and 50 million synapses. Despite this relative simplicity, figuring out how the brain of such a tiny fly works is still an ongoing process. Recently a big leap forward was made thanks to crowdsourced research, resulting in the FlyWire connectome map. Starting with high-resolution electron microscope data, the connections between the individual neurons (the connectome) was painstakingly pieced together, also using computer algorithms, but with validation by a large group of human volunteers using a game-like platform called EyeWire to perform said validation.

This work also includes identifying cell types, with over 8,000 different cell types identified. Within the full connectome subcircuits were identified, as part of an effort to create an ‘effectome’, i.e. a functional model of the physical circuits. With the finished adult female fruit fly connectome in hand, groups of researchers can now use it to make predictions and put these circuits alongside experimental contexts to connect activity in specific parts of the connectome to specific behavior of these flies.

Perhaps most interesting is how creating a game-like environment made the tedious work of reverse-engineering the brain wiring into something that the average person could help with, drastically cutting back the time required to create this connectome. Perhaps that crowdsourced research can also help with the ongoing process to map the human brain, even if that ups the scale of the dataset by many factors. Until we learn more, at this point even comprehending a fruit fly’s brain may conceivably give us many hints which could speed up understanding the human brain.

Featured image: “Drosophila Melanogaster Proboscis” by [Sanjay Acharya]

New Study Looks At The Potential Carcinogenicity Of 3D Printing

October 14, 2024 by Dan Maloney 39 Comments

We’ve all heard stories of the dangers of 3D printing, with fires from runaway hot ends or dodgy heated build plates being the main hazards. But what about the particulates? Can they actually cause health problems in the long run? Maybe, if new research into the carcinogenicity of common 3D printing plastics pans out.

According to authors [CheolHong Lim] and [DongSeok Seo], the research covered in this paper was undertaken because of reports of rare cancers among Korean STEM teachers, particularly those who used 3D printers in their curricula. It was thought that only long-term, continued exposure to the particulates generated by 3D printers could potentially be hazardous and that PLA was less likely to be hazardous than ABS. The study was designed to assess the potential carcinogenicity of both ABS and PLA particulates under conditions similar to what could be expected in an educational setting.

To do this, they generated particulates by heating ABS and PLA to extruder temperatures, collected and characterized them electrostatically, and dissolved them in the solvent DMSO. They used a cell line known as Balb/c, derived from fibroblasts of an albino laboratory mouse, to assess the cytotoxic concentration of each plastic, then conducted a comet assay, which uses cell shape as a proxy for DNA damage; damaged cells often take on a characteristically tailed shape that resembles a comet. This showed no significant DNA damage for either plastic.

But just because a substance doesn’t cause DNA damage doesn’t mean it can’t mess with the cell’s working in other ways. To assess this, they performed a series of cell transformation assays, which look for morphological changes as a result of treatment with a potential carcinogen. Neither ABS nor PLA were found to be carcinogenic in this assay. They also looked at the RNA of the treated cells, to assess the expression of genes related to carcinogenic pathways. They found that of 147 cancer-related genes, 113 were either turned up or turned down relative to controls. Finally, they looked at glucose metabolism as a proxy for the metabolic changes a malignant cell generally experiences, finding that both plastics increased metabolism in vitro.

Does this mean that 3D printing causes cancer? No, not by a long shot. But, it’s clear that under lab conditions, exposure to either PLA or ABS particulates seems to be related to some of the cell changes associated with carcinogenesis. What exactly this means in the real world remains to be seen, but the work described here at least sets the stage for further examination.

What does this all mean to the home gamer? For now, maybe you should at least crack a window while you’re printing.

The Biological Motors That Power Our Bodies

October 14, 2024 by Maya Posch 50 Comments

Most of us will probably be able to recall at least vaguely that a molecule called ATP is essential for making our bodies move, but this molecule is only a small part of a much larger system. Although we usually aren’t aware of it, our bodies consist of a massive collection of biological motors and related structures, which enable our muscles to contract, nutrients and fluids to move around, and our cells to divide and prosper. Within the biochemical soup that makes up single- and multi-cellular lifeforms, it are these mechanisms that turn a gooey soup into something that can do much more than just gently slosh around in primordial puddles.

There are many similarities between a single-cell organism like a bacteria and eukaryotic multi-cellular organisms like us humans, but the transition to the latter requires significantly more complicated structures. An example for this are cilia, which together with motor proteins like myosin and kinesin form the foundations of our body’s basic functioning. Quite literally supporting all this is the cytoskeleton, which is a feature that our eukaryotic cells have in common with bacteria and archaea, except that eukaryotic cytoskeletons are significantly more complex.

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Remembering John Wheeler: You’ve Definitely Heard Of His Work

October 12, 2024 by Donald Papp 9 Comments

Physicist John Archibald Wheeler made groundbreaking contributions to physics, and [Amanda Gefter] has a fantastic writeup about the man. He was undeniably brilliant, and if you haven’t heard of him, you have certainly heard of some of his students, not to mention his work.

Ever heard of wormholes? Black holes? How about the phrase “It from Bit”? Then you’ve heard of his work. All of those terms were coined by Wheeler; a knack for naming things being one of his talents. His students included Richard Feynman and Kip Thorne (if you enjoyed The Martian, you at least indirectly know of Kip Thorne) and more. He never won a Nobel prize, but his contributions were lifelong and varied.

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The US’s New Nuclear Weapons, Mysterious Fogbanks And Inertial Confinement Fusion

October 11, 2024 by Maya Posch 52 Comments

Keeping the United States’ nuclear arsenal ready for use is an ongoing process, one which is necessarily shrouded in complete secrecy. In an article by The War Zone these developments and the secrets behind it are touched upon, including a secret ingredient for these thermonuclear warheads that is only officially known as ‘Fogbank’, but which is very likely aerogel.

As noted by a commentator, this is pretty much confirmed in an article published by Los Alamos National Laboratories (LANL) in the 2nd 2009 issue (PDF) of Nuclear Weapons Journal. On page nine the article on hohlraum-based inertial confinement fusion notes the use of aerogel to tamp the radially inward motion of the wall material, suggesting a similar function within one of these thermonuclear warheads.

The research at the Nuclear Ignition Facility (NIF) over at Lawrence Livermore National Laboratory (LLNL) is directly related to these thermonuclear weapons, as they are based around inertial confinement fusion (ICF), which is what the NIF is set up for to study, including the role of aerogel. ICF is unlikely to ever be used for energy production, as we noted in the past, but makes it possible to study aspects of detonating a thermonuclear weapon that are difficult to simulate and illegal to test with real warheads.

Currently it seems that after decades of merely reusing the Fogbank material in refurbished warheads, new material is now being produced again, with it likely being used in the new W93 warhead and the low-yield W76 and life-extended W76-1 variants. All of which is of course pure conjecture, barring the details getting leaked on the War Thunder forums to settle a dispute on realistic US thermonuclear weapon yields.

On-Site Viral RNA Detection In Wastewater With Paper And Wax Microfluidics

October 9, 2024 by Maya Posch 4 Comments

Schematic version of on-site wastewater analysis using the microfluidic strips (Credit: Yuwei Pan et al., Cell, 2024)

Wastewater sampling has become a popular way over the years to keep track of the health of a population, including human ones, as pathogens are often detectable in the effluence from toilets. Since most houses connected to the centralized sewer systems, this means that a few sampling sites suffice to keep tabs on which viruses are circulating in an area. While sampling this wastewater is easy, the actual RNA analysis using PCR (polymerase chain reaction) still has to be performed in laboratories, adding complex logistics. An approach for on-site analysis using microfluidics was tested out by [Yuwei Pan] et al., as recently published in Cell.

This particular approach uses RT-LAMP (reverse-transcription loop-mediated isothermal amplification) to increase the amount of genetic material, which has the significant benefit over PCR that it does not require multiple thermal cycles, instead being run at a constant temperature. The filter paper used as the basis has wax microchannels printed on it, which help to guide the filtered wastewater to the reaction chambers. This is in many ways reminiscent of the all too familiar linear flow self-tests (RAT: rapid antigen test) that have become one of the hallmarks of the SARS-CoV-2 pandemic.

What this paper microfluidic device adds is that it doesn’t merely contain antigens, but performs the lysis (i.e. breakdown of the virus particles), genetic material multiplication using RT-LAMP and subsequent presence detection of certain RNA sequences to ascertain the presence of specific viruses. Having been used in the field already since 2020 in the UK, the researchers envision this type of on-site analysis to be combined with a smartphone for instant recording and transmission to health authorities.

Some of the benefits of this approach would be lower cost, easier logistics and faster results compared to shipping wastewater samples to central laboratories.

Lagrange Points And Why You Want To Get Stuck At Them

October 9, 2024 by Maya Posch 35 Comments

Visualization of the Sun-Earth Lagrange points.

Orbital mechanics is a fun subject, as it involves a lot of seemingly empty space that’s nevertheless full of very real forces, all of which must be taken into account lest one’s spacecraft ends up performing a sudden lithobraking maneuver into a planet or other significant collection of matter in said mostly empty space. The primary concern here is that of gravitational pull, and the way it affects one’s trajectory and velocity. With a single planet providing said gravitational pull this is quite straightforward to determine, but add in another body (like the Moon) and things get trickier. Add another big planetary body (or a star like our Sun), and you suddenly got yourself the restricted three-body problem, which has vexed mathematicians and others for centuries.

The three-body problem concerns the initial positions and velocities of three point masses. As they orbit each other and one tries to calculate their trajectories using Newton’s laws of motion and law of universal gravitation (or their later equivalents), the finding is that of a chaotic system, without a closed-form solution. In the context of orbital mechanics involving the Earth, Moon and Sun this is rather annoying, but in 1772 Joseph-Louis Lagrange found a family of solutions in which the three masses form an equilateral triangle at each instant. Together with earlier work by Leonhard Euler led to the discovery of what today are known as Lagrangian (or Lagrange) points.

Having a few spots in an N-body configuration where you can be reasonably certain that your spacecraft won’t suddenly bugger off into weird directions that necessitate position corrections using wasteful thruster activations is definitely a plus. This is why especially space-based observatories such as the James Webb Space Telescope love to hang around in these spots.

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