3D Printing Functional Human Brain Tissue For Research Purposes

February 12, 2024 by Maya Posch 18 Comments

Graphical summary of the newly developed 3D bioprinting process. (Credit: Yan et al., 2024)

The brain is probably the least explored organ, much of which is due to the difficulty of studying it in situ rather than in slices under a microscope. Even growing small organoids out of neurons provide few clues, as this is not how brain tissue is normally organized. A possible breakthrough may have been found here by a group of researchers whose article in Cell Stem Cell details how they created functional human neural tissues using a commercial 3D bioprinter.

As detailed by [Yuanwei Yan] and colleagues in their research article, the issue with previous approaches was that although these would print layers of neurons, they would fail to integrate as in the brain. In the brain’s tissues, we see a wide variety of neurons and supportive cells, all of which integrate in a specific way to form functioning neuron-to-neuron and neuron-to-glial connections with expected neural activity. The accomplishment of this research team is 3D bioprinting of neural tissues with the necessary functional connections.

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AI’s Existence Is All It Takes To Be Accused Of Being One

February 11, 2024 by Donald Papp 31 Comments

New technologies bring with them the threat of change. AI tools are one of the latest such developments. But as is often the case, when technological threats show up, they end up looking awfully human.

Recently, [E. M. Wolkovich] submitted a scientific paper for review that — to her surprise — was declared “obviously” the work of ChatGPT. No part of that was true. Like most people, [E. M. Wolkovich] finds writing a somewhat difficult process. Her paper represents a lot of time and effort. But despite zero evidence, this casual accusation of fraud in a scientific context was just sort of… accepted.

There are several reasons this is concerning. One is that, in principle, the scientific community wouldn’t dream of leveling an accusation of fraud like data manipulation without evidence. But a reviewer had no qualms about casually claiming [Wolkovich]’s writing wasn’t hers, effectively calling her a liar. Worse, at the editorial level, this baseless accusation was accepted and passed along with vague agreement instead of any sort of pushback.

Showing Your Work Isn’t Enough

Interestingly, [Wolkovich] writes everything in plain text using the LaTeX typesetting system, hosted on GitHub, complete with change commits. That means she could easily show her entire change history, from outline to finished manuscript, which should be enough to convince just about anyone that she isn’t a chatbot.

But pondering this raises a very good question: is [Wolkovich] having to prove she isn’t a chatbot a desirable outcome of this situation? We don’t think it is, nor is this an idle question. We’ve seen how even when an artist can present their full workflow to prove an AI didn’t make their art, enough doubt is sown by the accusation to poison the proceedings (not to mention greatly demoralizing the creator in the process.)

Better Standards Would Help

[Wolkovich] uses this opportunity to reflect on and share what this situation indicates about useful change. Now that AI tools exist, guidelines that acknowledge them should be created. Explicit standards about when and how AI tools can be used in the writing process, how those tools should be acknowledged if used, and a process to handle accusations of misuse would all be positive changes.

Because as it stands, it’s hard to see [Wolkovich]’s experience as anything other than an illustration of how a scientific community’s submission and review process was corrupted not by undeclared or thoughtless use of AI but by the simple fact that such tools exist. This seems like both a problem that will only get worse with time (right now, it is fairly easy to detect chatbots) and one that will not solve itself.

NIF’s Laser Fusion Experiment’s Energy Gain Passes Peer Review

February 9, 2024 by Maya Posch 53 Comments

Back in December of 2022, a team of researchers at the USA’s National Ignition Facility (NIF) announced that they had exceeded ‘scientific breakeven’ with their laser-based inertial confinement fusion (ICF) system. Their work has now been peer-reviewed and passed scrutiny, confirming that the energy put into fusing a small amount of deuterium-tritium fuel resulted in a net gain (Q) of 1.5.

Laser Bay 2, one of NIF's two laser bays — Laser Bay 2 at the NIF.

The key take-away here of course remains that ICF is not a viable method of producing energy, as we detailed back in 2021 when we covered the 1.3 MJ yield announcement, and again in 2022 following the subject of this now completed peer review. The sheer amount of energy required to produce the laser energy targeting the fuel capsule and loss therein, as well as the energy required to manufacture each of these fuel capsules (Hohlraum) and sustaining a cycle make it a highly impractical proposition for anything except weapons research.

Despite this, it’s good to see that the NIF’s ICF research is bearing fruit, even if for energy production we should look towards magnetic confinement fusion (MCF), which includes the many tokamaks active today like Japan’s JT-60SE, as well as stellarators like Germany’s Wendelstein 7-X and other efforts to make MCF a major clean-energy source for the future.

A schematic representation of the different ionospheric sub-layers and how they evolve daily from day to night periods. (Credit: Carlos Molina)

Will Large Satellite Constellations Affect Earth’s Magnetic Field?

February 7, 2024 by Maya Posch 48 Comments

Imagine taking a significant amount of metals and other materials out of the Earth’s crust and scattering it into the atmosphere from space. This is effectively what we have been doing ever since the beginning of the Space Age, with an increasing number of rocket stages, satellites and related objects ending their existence as they burn up in the Earth’s atmosphere. Yet rather than vanish into nothing, the debris of this destruction remains partially in the atmosphere, where it forms pockets of material. As this material is often conductive, it will likely affect the Earth’s magnetic field, as argued by [Sierra Solter-Hunt] in a pre-publication article.

A summary by [Dr. Tony Phillips] references a 2023 NASA research article by [Daniel M. Murphy] et al. which describes the discovery that about 10% of the aerosol particles in the stratosphere are aluminium and other metals whose origin can be traced back to the ‘burn-up’ of the aforementioned space objects. This is a factor which can increase the Debye length of the ionosphere. What the exact effects of this may be is still largely unknown, but fact remains that we are launching massively more objects into space than even a decade ago, with the number of LEO objects consequently increasing.

Although the speculation by [Sierra] can be called ‘alarmist’, the research question of what’ll happen if over the coming years we’ll have daily Starlink and other satellites disintegrating in the atmosphere is a valid one. As this looks like it will coat the stratosphere and ionosphere in particular with metal aerosols at levels never seen before, it might be worth it to do the research up-front, rather than wait until we see something odd happening.

Metal Crystal Stops Electrons

February 7, 2024 by Al Williams 14 Comments

Researchers at Rice University have found an alloy of copper, vanadium, and sulfur that forms crystals that, due to quantum effects, can trap electrons. This can produce flat bands, which have been observed in 2D crystals previously. The team’s results are the first case of a 3D crystal with that property.

The flat band term refers to the electron energy bands. Normally, the electrons change energy levels based on momentum. But in a flat band, this doesn’t occur. This implies that the electrons are nearly stationary, which leads to unique optical, electronic, and magnetic properties. In addition, flat-band materials often exhibit unusual behavior, such as exotic quantum states, ferromagnetism, or even superconductivity.

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Evidence For Graphite As A Room Temperature Superconductor

February 6, 2024 by Maya Posch 30 Comments

Magnetization M(H) hysteresis loops measured for the HOPG sample, before and after 800 K annealing to remove ferromagnetic influences. (Credit: Kopelevich et al., 2023)

Little has to be said about why superconducting materials are so tantalizing, or what the benefits of an ambient pressure, room temperature material with superconducting properties would be. The main problem here is not so much the ‘room temperature’ part, as metallic hydrogen is already capable of this feat, if at pressures far too high for reasonable use. Now a recent research article in Advanced Quantum Technologies by Yakov Kopelevich and colleagues provides evidence that superconducting properties can be found in cleaved highly oriented pyrolytic graphite (HOPG). The fact that this feat was reported as having been measured at ambient pressure and room temperature makes this quite noteworthy.

What is claimed is that the difference from plain HOPG is the presence of parallel linear defects that result from the cleaving process, a defect line in which the authors speculate that the strain gradient fluctuations result in the formation of superconducting islands, linked by the Josephson effect into Josephson junctions. In the article, resistance and magnetization measurements on the sample are described, which provide results that provide evidence for the presence of these junctions that would link superconducting islands on the cleaved HOPG sample together.

As with any such claim, it is of course essential that it is independently reproduced, which we are likely to see the results of before long. An interesting part of the claim made is that this type of superconductivity in linear defects of stacked materials could apply more universally, beyond just graphite. Assuming this research data is reproduced successfully, the next step would likely be to find ways to turn this effect into practical applications over the coming years and decades.

Avocado-Shaped Robot Makes Its Way Through The Rainforest

February 3, 2024 by Lewin Day 12 Comments

When you think of a robot getting around, you probably think of something on wheels or tracks. Maybe you think about a bipedal walking robot, more common in science fiction than our daily lives. In any case, researchers went way outside the norm when they built an avocado-shaped robot for exploring the rainforest.

The robot is the work of doctoral students at ETH Zurich, working with the Swiss Federal Institute for Forest, Snow, and Landscape research. The design is optimized for navigating the canopy of the rainforest, where a lot of the action is. Traditional methods of locomotion are largely useless up high in the trees, so another method was needed.

The avocado robot is instead tethered to a cable which is affixed to a high branch on a tree, or even potentially a drone flying above. The robot then uses a winch to move up and down as needed. A pair of ducted fans built into the body provide the thrust necessary to rotate and pivot around branches or other obstacles as it descends. It also packs a camera onboard to help it navigate the environment autonomously.

It’s an oddball design, but it’s easy to see how this design makes sense for navigating the difficult environment of a dense forest canopy. Sometimes, intractable problems require creative solutions. Continue reading “Avocado-Shaped Robot Makes Its Way Through The Rainforest” →