Broken Genes And Scrambled Proteins: How Radiation Causes Biological Damage

If decades of cheesy sci-fi and pop culture have taught us anything, it’s that radiation is a universally bad thing that invariably causes the genetic mutations that gifted us with everything from Godzilla to Blinky the Three-Eyed Fish. There’s a kernel of truth there, of course. One only needs to look at pictures of what happened to Hiroshima survivors or the first responders at Chernobyl to see extreme examples of what radiation can do to living tissues.

But as is usually the case, a closer look at examples a little further away from the extremes can be instructive, and tell us a little more about how radiation, both ionizing and non-ionizing, can cause damage to biochemical structures and processes. Doing so reveals that, while DNA is certainly in the crosshairs for damage by radiation, it’s not the only target — proteins, carbohydrates, and even the lipids that form the membranes within cells are subject to radiation damage, both directly and indirectly. And the mechanisms underlying all of this end up revealing a lot about how life evolved, as well as being interesting in their own right.

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This Scratch-Built X-Ray Tube Really Shines

On no planet is making your own X-ray tube a good idea. But that doesn’t mean we’re not going to talk about it, because it’s pretty darn cool.

And when we say making an X-ray tube, we mean it — [atominik] worked from raw materials, like glass test tubes, tungsten welding electrodes, and bits of scrap metal, to make this dangerously delightful tube. His tool setup was minimalistic as well– where we might expect to see a glassblower’s lathe like the ones used by [Dalibor Farny] to make his custom Nixie tubes, [atominik] only had a small oxy-propane hand torch to work with. The only other specialized tools, besides the obvious vacuum pump, was a homebrew spot welder, which was used to bond metal components to the tungsten wires used for the glass-to-metal seals.

Although [atominik] made several versions, the best tube is a hot cathode design, with a thoriated tungsten cathode inside a copper focusing cup. Across from that is the anode, a copper slug target with an angled face to direct the X-rays perpendicular to the long axis of the tube. He also included a titanium electrode to create a getter to scavenge oxygen and nitrogen and improve the vacuum inside the tube. All in all, it looks pretty similar to a commercial dental X-ray tube.

The demonstration in the video below is both convincing and terrifying. He doesn’t mention the voltage he’s using across the anode, but from the cracking sound we’d guess somewhere around 25- to 30 kilovolts. The tube really gets his Geiger counter clicking.

Here’s hoping [atominik] is taking the proper precautions during these experiments, and that you do too if you decide to replicate this. You’ll also probably want to check out our look at the engineering inside commercial medical X-ray tubes.

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Homemade CAT Scan Shouldn’t Scan Cats

[Pyrotechnical] thought about buying a CAT scanner and found out they cost millions of dollars. So he decided to build one for about $200 using a salvage X-ray tube and some other miscellaneous parts. A scintillating detector provides the image for pick up with a camera phone. The control? An Arduino, what else? You can watch the video below, but due to plenty of NSFW language, you might want to put your headphones on if you don’t want to shock anyone.

Of course, you need to be careful when working with energetic X-rays. To keep away from the X-ray source, [Pyrotechnical] used a Roku remote and an IR sensor to control the device from afar. The electronics is pretty easy. You just have to rotate a turntable and trigger the camera while lighting up the X-ray tube.

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CT Scans Help Reverse Engineer Mystery Module

The degree to which computed tomography has been a boon to medical science is hard to overstate. CT scans give doctors a look inside the body that gives far more information about the spatial relationship of structures than a plain X-ray can. And as it turns out, CT scans are pretty handy for reverse engineering mystery electronic modules, too.

The fact that the mystery module in question is from Apollo-era test hardware leaves little room for surprise that [Ken Shirriff] is the person behind this fascinating little project. You’ll recall that [Ken] recently radiographically reverse engineered a pluggable module of unknown nature, using plain X-ray images taken at different angles to determine that the undocumented Motorola module was stuffed full of discrete components that formed part of a square wave to sine wave converter.

The module for this project, a flip-flop from Motorola and in the same form factor, went into an industrial CT scanner from an outfit called Lumafield, where X-rays were taken from multiple angles. The images were reassembled into a three-dimensional view by the scanner’s software, which gave a stunningly clear view of the components embedded within the module’s epoxy body. The cordwood construction method is obvious, and it’s pretty easy to tell what each component is. The transistors are obvious, as are the capacitors and diodes. The resistors were a little more subtle, though — careful examination revealed that some are carbon composition, while others are carbon film. It’s even possible to pick out which diodes are Zeners.

The CT scan data, along with some more traditional probing for component values, let [Ken] reverse engineer the whole circuit, which turned out to be a little different than a regular J-K flip-flop. Getting a non-destructive look inside feels a little like sitting alongside the engineers who originally built these things, which is pretty cool.

Reverse Engineering An Apollo-Era Module With X-Ray

The gear that helped us walk on the Moon nearly 60 years ago is still giving up its mysteries today, with some equipment from the Apollo era taking a little bit more effort to reverse engineer than others. A case in point is this radiographic reverse engineering of some Apollo test gear, pulled off by [Ken Shirriff] with help from his usual merry band of Apollo aficionados.

The item in question is a test set used for ground testing of the Up-Data Link, which received digital commands from mission controllers. Contrary to the highly integrated construction used in Apollo flight hardware, the test set, which was saved from a scrapyard, used more ad hoc construction, including cards populated by mysterious modules. The pluggable modules bear Motorola branding, and while they bear some resemblance to ICs, they’re clearly not.

[Ken] was able to do some preliminary reverse-engineering using methods we’ve seen him employ before, but ran into a dead end with his scope and meter without documentation. So the modules went under [John McMaster]’s X-ray beam for a peek inside. They discovered that the 13-pin modules are miniature analog circuits using cordwood construction, with common discrete passives stacked vertically between parallel PCBs. The module they imaged showed clear shadows of carbon composition resistors, metal-film capacitors, and some glass-body diodes. Different angles let [Ken] figure out the circuit, which appears to be part of a square wave to sine wave converter.

The bigger mystery here is why the original designer chose this method of construction. There must still be engineers out there who worked on stuff like this, so here’s hoping they chime in on this innovative method.

X-ray image of a camera lens

Observing A Plant’s Vascular System With X-Ray Video

[Ben Krasnow] has a knack for showing us what’s inside of things while they’re moving. This week’s Applied Science experiment has him making time-lapse X-ray videos of things. This plant’s vascular system is just one of a few examples, the others being a dial clock and the zoom lens on a DSLR.

X-ray of plantThe trick here is having an X-ray sensing panel that can be reused. It takes around five seconds of exposure to grab each 40×40 cm frame which are then assembled back into video.

Now watching mechanisms move is cool — [Ben’s] video back in 2015 to show what a phonograph needle in the groove of a vinyl record looks like under a scanning electron microscope is still one for the coolest “camera tricks” we’ve ever seen pulled off. But watching the vascular system of a plant function is the recipe for one of those ah-ha educational moments, so we hope that 7th-grade biology teachers everywhere will find their way to this video.

The apparatus is described in great detail, but regular Hackaday readers will most likely want to focus in on the teardown of the X-ray panel, which [Ben] describes as a giant digital camera sensor tuned for receiving the X-rays. The source is a 50 kV 1 mA tube that he compares to what is used at the dental office. (Obviously this requires forethought to ensure his automated time-lapse setup will fail safe with the X-ray tube.) A Cyclone III FPGA drives the panel, communicating with the sensor array via two Ethernet interfaces.

A friend sent a the broken panel to [Ben] and he was able to easily repair a MOSFET that got knocked out of place. [biluni] shows up in the comments of this video, sharing his recollection from working in the industry 15 years ago that a panel like this would have cost $150k! But considering the stellar resolution, and repeatable use, it sure as heck beats the old film process.

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Better History Through X-Rays

Even if you aren’t a giant history buff, you probably know that the French royal family had some difficulties in the late 1700s. The end of the story saw the King beheaded and, a bit later, his wife the famous Marie Antoinette suffered the same fate. Marie wrote many letters to her confidant, and probable lover, Swedish count Axel von Fersen. Some of those letters have survived to the present day — sort of. An unknown person saw fit to blot out parts of the surviving letters with ink, rendering them illegible. Well, that is, until now thanks to modern x-ray technology.

Anne Michelin from the French National Museum of Natural History and her colleagues were able to foil the censor and they even have a theory as to the ink blot’s origin: von Fersen, himself! The technique used may enable the recovery of other lost portions of historical documents and was published in the journal Science Advances.

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