Biosynthesis Of Polyester Amides In Engineered Escherichia Coli

March 22, 2025 by Maya Posch 8 Comments

Polymers are one of the most important elements of modern-day society, particularly in the form of plastics. Unfortunately most common polymers are derived from fossil resources, which not only makes them a finite resource, but is also problematic from a pollution perspective. A potential alternative being researched is that of biopolymers, in particular those produced by microorganisms such as everyone’s favorite bacterium Escherichia coli (E. coli).

These bacteria were the subject of a recent biopolymer study by [Tong Un Chae] et al., as published in Nature Chemical Biology (paywalled, break-down on Arstechnica).

By genetically engineering E. coli bacteria to use one of their survival energy storage pathways instead for synthesizing long chains of polyester amides (PEAs), the researchers were able to make the bacteria create long chains of mostly pure PEA. A complication here is that this modified pathway is not exactly picky about what amino acid monomers to stick onto the chain next, including metabolism products.

Although using genetically engineered bacteria for the synthesis of products on an industrial scale isn’t uncommon (see e.g. the synthesis of insulin), it would seem that biosynthesis of plastics using our prokaryotic friends isn’t quite ready yet to graduate from laboratory experiments.

Producing Syngas From CO2 And Sunlight With Direct Air Capture

March 21, 2025 by Maya Posch 17 Comments

The prototype DACCU device for producing syngas from air. (Credit: Sayan Kar, University of Cambridge)

There is more carbon dioxide (CO₂) in the atmosphere these days than ever before in human history, and while it would be marvelous to use these carbon atoms for something more useful, capturing CO₂ directly from the air isn’t that easy. After capturing it would also be great if you could do something more with it than stuff it into a big hole. Something like producing syngas (CO + H₂) for example, as demonstrated by researchers at the University of Cambridge.

Among the improvements claimed in the paper as published in Nature Energy for this direct air capture and utilization (DACCU) approach are that it does not require pure CO₂ feedstock, but will adsorb it directly from the air passing over a bed of solid silica-amine. After adsorption, the CO₂ can be released again by exposure to concentrated light. Following this the conversion to syngas is accomplished by passing it over a second bed consisting of silica/alumina-titania-cobalt bis(terpyridine), that acts as a photocatalyst.

The envisioned usage scenario would be CO2 adsorption during the night, with concentrated solar power releasing it the day with subsequent production of syngas. Inlet air would be passed only over the adsorption section before switching the inlet off during the syngas generating phase. As a lab proof-of-concept it seems to work well, with outlet air stripped from virtually all CO₂ and very high conversion ratio from CO₂ to syngas.

Syngas has historically been used as a replacement for gasoline, but is also used as a source of hydrogen (e.g. steam reformation (SMR) of natural gas) where it’s used for reduction of iron ore, as well as the production of methanol as a precursor to many industrial processes. Whether this DACCU approach provides a viable alternative to SMR and other existing technologies will become clear once this technology moves from the lab into the real world.

Thanks to [Dan] for the tip.

So What Is A Supercomputer Anyway?

March 19, 2025 by Maya Posch 33 Comments

Over the decades there have been many denominations coined to classify computer systems, usually when they got used in different fields or technological improvements caused significant shifts. While the very first electronic computers were very limited and often not programmable, they would soon morph into something that we’d recognize today as a computer, starting with World War 2’s Colossus and ENIAC, which saw use with cryptanalysis and military weapons programs, respectively.

The first commercial digital electronic computer wouldn’t appear until 1951, however, in the form of the Ferranti Mark 1. These 4.5 ton systems mostly found their way to universities and kin, where they’d find welcome use in engineering, architecture and scientific calculations. This became the focus of new computer systems, effectively the equivalent of a scientific calculator. Until the invention of the transistor, the idea of a computer being anything but a hulking, room-sized monstrosity was preposterous.

A few decades later, more computer power could be crammed into less space than ever before including ever higher density storage. Computers were even found in toys, and amidst a whirlwind of mini-, micro-, super-, home-, minisuper- and mainframe computer systems, one could be excused for asking the question: what even is a supercomputer?

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The Capacitor Plague Of The Early 2000s

March 18, 2025 by Maya Posch 54 Comments

Somewhere between the period of 1999 and 2007 a plague swept through the world, devastating lives and businesses. Identified by a scourge of electrolytic capacitors violently exploding or splurging their liquid electrolyte guts all over the PCB, it led to a lot of finger pointing and accusations of stolen electrolyte formulas. In a recent video by [Asianometry] this story is summarized.

Blown electrolytic capacitors. (Credit: Jens Both, Wikimedia)

The bad electrolyte in the faulty capacitors lacked a suitable depolarizer, which resulted in more gas being produced, ultimately leading to build-up of pressure and the capacitor ultimately failing in a way that could be rather benign if the scored top worked as vent, or violently if not.

Other critical elements in the electrolyte are passivators, to protect the aluminium against the electrolyte’s effects. Although often blamed on a single employee stealing an (incomplete) Rubycon electrolyte formula, the video questions this narrative, as the problem was too widespread.

More likely it coincided with the introduction of low-ESR electrolytic capacitors, along with computers becoming increasingly more power-hungry, and thus stressing the capacitors in a much warmer environment than in the early 1990s. Combine this with the presence of counterfeit capacitors in the market and the truth of what happened to cause the Capacitor Plague probably involves a bit from each column, a narrative that seems to be the general consensus.

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Checking In On The ISA Wars And Its Impact On CPU Architectures

March 18, 2025 by Maya Posch 33 Comments

An Instruction Set Architecture (ISA) defines the software interface through which for example a central processor unit (CPU) is controlled. Unlike early computer systems which didn’t define a standard ISA as such, over time the compatibility and portability benefits of having a standard ISA became obvious. But of course the best part about standards is that there are so many of them, and thus every CPU manufacturer came up with their own.

Throughout the 1980s and 1990s, the number of mainstream ISAs dropped sharply as the computer industry coalesced around a few major ones in each type of application. Intel’s x86 won out on desktop and smaller servers while ARM proclaimed victory in low-power and portable devices, and for Big Iron you always had IBM’s Power ISA. Since we last covered the ISA Wars in 2019, quite a lot of things have changed, including Apple shifting its desktop systems to ARM from x86 with Apple Silicon and finally MIPS experiencing an afterlife in the form of LoongArch.

Meanwhile, six years after the aforementioned ISA Wars article in which newcomer RISC-V was covered, this ISA seems to have not made the splash some had expected. This raises questions about what we can expect from RISC-V and other ISAs in the future, as well as how relevant having different ISAs is when it comes to aspects like CPU performance and their microarchitecture.

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Repairing A Legendary Elka Synthex Analog Synthesizer

March 17, 2025 by Maya Posch 16 Comments

Handy diagnostic LEDs on the side of the tone generator boards. (Credit: Mend it Mark, YouTube)

Somehow, an Elka Synthex analog synthesizer made it onto [Mend it Mark]’s repair bench recently. It had a couple of dud buttons, and some keys produced the wrong tone. Remember, this is an analog synthesizer from the 1980s, so we’re talking basic 74LS chips and kin. Fortunately, Elka helped him with the complete repair manual, including schematics.

As usual, [Mark] starts by diagnosing the faults, using the schematics to mark the parts of the circuitry to focus on. Then, the synth’s bonnet is popped open to reveal its absolutely gobsmackingly delightful inner workings, with neatly modular PCBs attached to a central backplane. The entire unit is controlled by a 6502 MPU, with basic counter ICs handling tone generation, controlled by top panel settings.

The Elka Synthex is a polyphonic analog synthesizer produced from 1981 to 1985 and used by famous artists, including Jean-Michel Jarre. Due to its modular nature, [Mark] was quickly able to hunt down the few defective 74LS chips and replace them before testing the instrument by playing some synth tunes from Jean-Michel Jarre’s Oxygène album, as is proper with a 1980s synthesizer.

Looking for something simpler? Or, perhaps, you want something not quite that simple.

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Blue Ghost Watches Lunar Eclipse From The Lunar Surface

March 16, 2025 by Maya Posch 20 Comments

Firefly’s Blue Ghost lander's first look at the solar eclipse as it began to emerge from its Mare Crisium landing site on March 14 at 5:30 AM UTC. (Credit: Firefly Aerospace) — Firefly’s Blue Ghost lander’s first look at the solar eclipse as it began to emerge from its Mare Crisium landing site on March 14 at 5:30 AM UTC. (Credit: Firefly Aerospace)

After recently landing at the Moon’s Mare Crisium, Firefly’s Blue Ghost lunar lander craft was treated to a spectacle that’s rarely observed: a total solar eclipse as seen from the surface of the Moon. This entire experience was detailed on the Blue Ghost Mission 1 live blog. As the company notes, this is the first time that a commercial entity has been able to observe this phenomenon.

During this event, the Earth gradually moved in front of the Sun, as observed from the lunar surface. During this time, the Blue Ghost lander had to rely on its batteries as it was capturing the solar eclipse with a wide-angle camera on its top deck.

Unlike the Blood Moon seen from the Earth, there was no such cool effect observed from the Lunar surface. The Sun simply vanished, leaving a narrow ring of light around the Earth. The reason for the Blood Moon becomes obvious, however, as the refracting of the sunlight through Earth’s atmosphere changes the normal white-ish light to shift to an ominous red.

The entire sequence of images captured can be observed in the video embedded on the live blog and below, giving a truly unique view of something that few humans (and robots) have so far been able to observe.

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