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Will This Be on the (Drug) Test? On Poppy Seeds and False Positives

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The other day, I caught a few minutes of the Seinfeld episode where Elaine Benes fails a drug test at work thanks to her fondness for the poppy seed muffins at Monk’s coffee shop. Can something as innocuous and innocent as a poppy seed pastry really make you look like a junkie?

Although opium is processed from the latex sap of the opium poppy (Papaver somniferum) and opiates are then extracted from that sap, all parts of the plant can contain or carry opium alkaloids, and the seeds often have a slight coating of the alkaloids from being in contact with the “seed pods.”


Because of this, opiates can be detected in urine sometimes up to 48 hours after ingestion of poppy seeds, which used to cause plenty of false positives on drug tests. You don’t “get high” from eating them, though, because the alkaloids break down at a relatively low temperatures. After baking, they’re still detectable, but too broken down to produce their well-known side-effects. It’s also worth noting that not all poppy seeds come from P. somniferum, the opium poppy.

Drug tests today have largely eliminated pastry-induced false positives.

The first part of this is using a two-step process where an immunoassay screening test identifies true negative samples and then, if necessary, a GC/MS (Gas Chromatography/Mass Spectrometry) confirmation testing — which identifies drug metabolites at the molecular level — is used on “non-negative” samples to rule out interfering substances.

The second fix is that, in 1998, the Department of Health and Human Services raised the screening and cutoff levels for the Opiate class from 300ng/mL to 2000 ng/mL, which helps to eliminate poppy seed interference with initial immunoassay screening.

It’s hard to make blanket statements about how many poppy seeds need to be ingested for a false positive — several factors that influences that, like body weight, vary from person to person — but a 1998 study [PDF] in Forensic Science International found that eating slices of cake with an average of 4.69 grams of poppy seeds on them was enough to cause four subjects to screen positive for up to 24 hours, with one person showing opiate levels of 302.1 ng/ml.

This is not an all-clear to go hogwild on poppyseeds, of course. Science blogger David Kroll wrote last year about a reader whose 17-year-old son died from drinking too much poppy seed tea:

"…Related specifically to Tom's comment, he has courageously posted a redacted version of the medical examiner's report from 13 Sept 2003. Therein, the toxicology analysis of tissues, blood, and the tea his son ingested are detailed. On the third page, the content of the tea was quantified as having a "high level of morphine," 259 micrograms/mL [equivalent to 259,000 nanograms, the measurement used in drug tests mentioned above]. Calculating a lethal dose for morphine is difficult because previous use of morphine can causes significant tolerance, or resistance, to both the therapeutic and lethal effects of the drug. For example, a dose of 100-150 mg may be lethal to a person who has never taken morphine orally, but it is not unusual for cancer patients with chronic pain to take as much as 4,000 mg/day.

Therefore, Tom's son could've received a lethal dose by drinking as little as a pint of the poppy tea he had prepared. [emphasis mine]

The medical examiner himself concluded the opinion section of the report by saying:

“Poppy seeds are the natural source of opioid analgesics. Although they contain extremely low levels of the drug, concentration of these compounds by brewing can result in potentially lethal levels.” [emphasis Kroll’s]

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iStock // Ekaterina Minaeva
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Man Buys Two Metric Tons of LEGO Bricks; Sorts Them Via Machine Learning
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iStock // Ekaterina Minaeva

Jacques Mattheij made a small, but awesome, mistake. He went on eBay one evening and bid on a bunch of bulk LEGO brick auctions, then went to sleep. Upon waking, he discovered that he was the high bidder on many, and was now the proud owner of two tons of LEGO bricks. (This is about 4400 pounds.) He wrote, "[L]esson 1: if you win almost all bids you are bidding too high."

Mattheij had noticed that bulk, unsorted bricks sell for something like €10/kilogram, whereas sets are roughly €40/kg and rare parts go for up to €100/kg. Much of the value of the bricks is in their sorting. If he could reduce the entropy of these bins of unsorted bricks, he could make a tidy profit. While many people do this work by hand, the problem is enormous—just the kind of challenge for a computer. Mattheij writes:

There are 38000+ shapes and there are 100+ possible shades of color (you can roughly tell how old someone is by asking them what lego colors they remember from their youth).

In the following months, Mattheij built a proof-of-concept sorting system using, of course, LEGO. He broke the problem down into a series of sub-problems (including "feeding LEGO reliably from a hopper is surprisingly hard," one of those facts of nature that will stymie even the best system design). After tinkering with the prototype at length, he expanded the system to a surprisingly complex system of conveyer belts (powered by a home treadmill), various pieces of cabinetry, and "copious quantities of crazy glue."

Here's a video showing the current system running at low speed:

The key part of the system was running the bricks past a camera paired with a computer running a neural net-based image classifier. That allows the computer (when sufficiently trained on brick images) to recognize bricks and thus categorize them by color, shape, or other parameters. Remember that as bricks pass by, they can be in any orientation, can be dirty, can even be stuck to other pieces. So having a flexible software system is key to recognizing—in a fraction of a second—what a given brick is, in order to sort it out. When a match is found, a jet of compressed air pops the piece off the conveyer belt and into a waiting bin.

After much experimentation, Mattheij rewrote the software (several times in fact) to accomplish a variety of basic tasks. At its core, the system takes images from a webcam and feeds them to a neural network to do the classification. Of course, the neural net needs to be "trained" by showing it lots of images, and telling it what those images represent. Mattheij's breakthrough was allowing the machine to effectively train itself, with guidance: Running pieces through allows the system to take its own photos, make a guess, and build on that guess. As long as Mattheij corrects the incorrect guesses, he ends up with a decent (and self-reinforcing) corpus of training data. As the machine continues running, it can rack up more training, allowing it to recognize a broad variety of pieces on the fly.

Here's another video, focusing on how the pieces move on conveyer belts (running at slow speed so puny humans can follow). You can also see the air jets in action:

In an email interview, Mattheij told Mental Floss that the system currently sorts LEGO bricks into more than 50 categories. It can also be run in a color-sorting mode to bin the parts across 12 color groups. (Thus at present you'd likely do a two-pass sort on the bricks: once for shape, then a separate pass for color.) He continues to refine the system, with a focus on making its recognition abilities faster. At some point down the line, he plans to make the software portion open source. You're on your own as far as building conveyer belts, bins, and so forth.

Check out Mattheij's writeup in two parts for more information. It starts with an overview of the story, followed up with a deep dive on the software. He's also tweeting about the project (among other things). And if you look around a bit, you'll find bulk LEGO brick auctions online—it's definitely a thing!

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Cs California, Wikimedia Commons // CC BY-SA 3.0
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How Experts Say We Should Stop a 'Zombie' Infection: Kill It With Fire
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Cs California, Wikimedia Commons // CC BY-SA 3.0

Scientists are known for being pretty cautious people. But sometimes, even the most careful of us need to burn some things to the ground. Immunologists have proposed a plan to burn large swaths of parkland in an attempt to wipe out disease, as The New York Times reports. They described the problem in the journal Microbiology and Molecular Biology Reviews.

Chronic wasting disease (CWD) is a gruesome infection that’s been destroying deer and elk herds across North America. Like bovine spongiform encephalopathy (BSE, better known as mad cow disease) and Creutzfeldt-Jakob disease, CWD is caused by damaged, contagious little proteins called prions. Although it's been half a century since CWD was first discovered, scientists are still scratching their heads about how it works, how it spreads, and if, like BSE, it could someday infect humans.

Paper co-author Mark Zabel, of the Prion Research Center at Colorado State University, says animals with CWD fade away slowly at first, losing weight and starting to act kind of spacey. But "they’re not hard to pick out at the end stage," he told The New York Times. "They have a vacant stare, they have a stumbling gait, their heads are drooping, their ears are down, you can see thick saliva dripping from their mouths. It’s like a true zombie disease."

CWD has already been spotted in 24 U.S. states. Some herds are already 50 percent infected, and that number is only growing.

Prion illnesses often travel from one infected individual to another, but CWD’s expansion was so rapid that scientists began to suspect it had more than one way of finding new animals to attack.

Sure enough, it did. As it turns out, the CWD prion doesn’t go down with its host-animal ship. Infected animals shed the prion in their urine, feces, and drool. Long after the sick deer has died, others can still contract CWD from the leaves they eat and the grass in which they stand.

As if that’s not bad enough, CWD has another trick up its sleeve: spontaneous generation. That is, it doesn’t take much damage to twist a healthy prion into a zombifying pathogen. The illness just pops up.

There are some treatments, including immersing infected tissue in an ozone bath. But that won't help when the problem is literally smeared across the landscape. "You cannot treat half of the continental United States with ozone," Zabel said.

And so, to combat this many-pronged assault on our wildlife, Zabel and his colleagues are getting aggressive. They recommend a controlled burn of infected areas of national parks in Colorado and Arkansas—a pilot study to determine if fire will be enough.

"If you eliminate the plants that have prions on the surface, that would be a huge step forward," he said. "I really don’t think it’s that crazy."

[h/t The New York Times]

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