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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Cockroaches In Space: Waste Processing And A Healthy Protein Source Combined

October 12, 2024 by Maya Posch 51 Comments

As the current frontier of humanity in space, the International Space Station is heavily reliant on Earth not only for fresh supplies but also as a garbage disposal service for the various types of waste produced on the ISS by its human occupants. As future manned missions take humans further away from Earth, finding ways to reprocess this waste rather than chucking it out of the nearest airlock becomes a priority. One suggested solution comes from a Polish company, Astronika, with their insect bioreactor that can process organic material into useful biomass.

Interestingly, the cockroach species picked was the Madagascar hissing cockroach, one of the largest (5 – 7.5 cm) species. This is also a cockroach species which is often kept as a pet. In this closed-loop bioreactor that Astronika has developed, these cockroaches would chew their way through up to 3.6 kg of waste per week in the large version, with the adult cockroaches presumably getting turned into fresh chow and various materials at some point. Beyond the irrational ‘yuck’ factor that comes with eating insect protein, one of the biggest issues we can see with this system is that the long-duration mission crew may get attached to the cockroaches, as they are rather cute.

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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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Running Game Boy Games On STM32 MCUs Is Peanuts

October 8, 2024 by Maya Posch 3 Comments

Using a STM32F429 Discovery board [Jan Zwiener] put together a Game Boy-compatible system called STM32Boy. It is based around the Peanut-GB Game Boy emulator core, which is a pretty nifty and fast single-header GB emulator library in C99. Considering that the average 32-bit MCU these days is significantly faster than the ~4 MHz 8-bit Sharp SM83 (Intel 8080/Zilog Z80 hybrid) in the original Game Boy it’s probably no surprise that the STM32F429 (up to 180 MHz) can emulate this 8-bit SoC just fine.

Since Peanut-GB is a library, the developer using it is expected to provide their own routines to read and write RAM and ROM and to handle errors. Optional are the line drawing, audio read/write and serial Tx/Rx functions, with the library providing reset and a host of other utility functions. Audio functionality is provided externally, such as using the provided MiniGB APU. Although fast, it comes with a range of caveats that limit compatibility and accuracy.

For STM32Boy, [Jan] uses the LCD screen that’s on the STM32 development board to render the screen on, along with a Game Boy skin. The LCD’s touch feature is then used for the controls, as can be elucidated from the main source file. Of note is that the target GB ROM is directly compiled into the firmware image rather than provided via an external SD card. This involves using the xxd tool to create a hex version of the ROM image that can be included. Not a bad way to get a PoC up and running, but we imagine that if you want to create a more usable GB-like system it should at least be able to play more than one game without having to reflash the MCU.

Using Donor Immune Cells To Mass-Produce CAR-T Autoimmune Therapies

October 7, 2024 by Maya Posch 3 Comments

As exciting as immunotherapies are in terms of fighting cancer, correcting autoimmune disorders and so on, they come with a major disadvantage. Due to the current procedure involving the use of a patient’s own immune (T) cells, this making such therapies rather expensive and involved for the patient. Recent research has therefore focused on answering the question whether T cells from healthy donors could be somehow used instead, with promising results from a recent study on three human patients, as reported in Nature.

The full study results (paywalled) by [Xiaobing Wang] et al. are published in Cell, with the clinical trial details available on the ClinicalTrials.gov website. For this particular trial the goal was to attempt to cure the autoimmune conditions of the three study participants (being necrotizing myopathy (IMNM) and diffuse cutaneous systemic sclerosis (dcSSc)). The T cells used in the study were obtained from a healthy 21-year old woman, and modified with chimeric antigen receptors targeting B (memory) cells. Using CRISPR-Cas9 the T cells were then further modified to prevent the donor cells from attacking the patient’s cells and vice versa.

After injection, the CAR-T cells got to work, multiplying and seeking out the target B cells, including the pathogenic ones underlying the autoimmune conditions. This persisted for a few weeks until the CAR-T cells effectively vanished and new B cells began to emerge, with a clear decrease in autoantibodies. Two months after beginning treatment, all three participants noted marked improvements in their conditions, which persisted at 6 months. For the woman with IMNM, muscle strength had increased dramatically with undetectable autoantibody levels, and the two men with dcSSc saw scar tissue formation reversed and their skin condition improve massively.

It remains to be seen whether this period of remission in these patients is permanent, and whether there any side effects of CAR-T cell therapy. We previously reported on CAR-T cell therapies and the many promises which they hold. Depending on the outcome of these early trials, it could mean that autoimmune conditions, allergies and cancer will soon be worries of the past, marking another massive medical milestone not unlike the invention of vaccines and the discovery of antibiotics.