A safer way to train detection dogs

K9 chemistry: A safer way to train detection dogs
A detection dog in training. Credit: Courtesy of Auburn University College of Veterinary Medicine

Trained dogs are incredible chemical sensors, far better at detecting explosives, narcotics and other substances than even the most advanced technological device. But one challenge is that dogs have to be trained, and training them with real hazardous substances can be inconvenient and dangerous.


NIST scientists have been working to solve this problem using a jello-like material called polydimethylsiloxane, or PDMS for short. PDMS absorbs odors and releases them slowly over time. Enclose it in a container with an explosive or narcotic for a few weeks until it absorbs the odors, and you can then use it to safely train dogs to detect the real thing.

But a few weeks is a long time, and now, NIST researchers have developed a faster way to infuse PDMS with vapors. In the journal Forensic Chemistry, they describe warming compounds found in explosives, causing them to release vapors more quickly, then capturing those vapors with PDMS that is maintained at a cooler temperature, which allows it to absorb vapors more readily. This two-temperature method cut the time it took to “charge” PDMS training aids from a few weeks to a few days.

“That time savings can be critical,” said NIST research chemist Bill MacCrehan. “If terrorists are using a new type of explosive, you don’t want to wait a month for the training aids to be ready.”

For this experiment, MacCrehan infused PDMS with vapors from dinitrotoluene (DNT), which is a low-level contaminant present in TNT explosives but the main odorant that dogs respond to when detecting TNT. He also infused PDMS with vapors from a small quantity of TNT. Co-authors at the Auburn University College of Veterinary Medicine then demonstrated that trained detection dogs responded to the DNT-infused PDMS training aids as if they were real TNT.

While this study focused on DNT as a proof of concept, MacCrehan says he believes the two-temperature method will also work with other explosives and with narcotics such as fentanyl. Some forms of fentanyl are so potent that inhaling a small amount can be harmful or fatal to humans and dogs. But by controlling how much vapor the PDMS absorbs, MacCrehan says, it should be possible to create safe training aids for fentanyl.

Other safe training aids already exist. Some are prepared by dissolving explosives and applying the solution to glass beads, for example. “But most have not been widely accepted in the canine detection community because their effectiveness has not been proven,” said Paul Waggoner, a co-author and co-director of Auburn’s Canine Performance Sciences Program. “If you put an explosive in a solvent, the dogs might actually be detecting the solvent, not the explosive.”

To test the two-temperature method, MacCrehan devised a PDMS “charging station” with a hot plate on one side and a cooling plate on the other (so the “hot stays hot and the cool stays cool,” as a 1980s commercial jingle put it). He prepared various samples

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Animal hospital at Tufts University has seen about a dozen dogs for eating face masks

Face masks are helping keep people safe during the COVID pandemic but they are posing a risk to dogs.

The Foster Hospital for Small Animals at Tufts University in Grafton said they have seen about a dozen dogs that have eaten face masks, some of which have needed emergency surgery.

Catherine Stecyk, a surgeon and resident at the Foster Hospital said she could see the “fitted nosepiece of a face mask” using x-rays on King, a 2-year-old Labrador retriever.

“We took King to emergency surgery, where I felt two wads of material,” said Stecyk. “One was stuck in the stomach and extending into the beginning of the small intestine, causing it to bunch up, and the other one was a bit farther down the intestine. The intestine was inflamed and bruised, but not yet traumatized to the point of perforation, which was really lucky.”

The 2-year-old Lab was able to make a full recovery, but Stecyk warns dog owners that it could’ve been a lot worse.

“Face masks are pretty new to daily life for most of us,” said veterinarian Elizabeth Rozanski. “Some dog owners may be used to their pet being OK after eating a greasy paper towel or pooping out a sock. However, they need to know that cloth masks and the medical-grade paper masks don’t dissolve that quickly, and the ties or ear loops can lead to a dangerous linear obstruction.”

The animal hospital warns owners to keep masks out of reach, discard masks properly when outside the home and contact a veterinarian immediately if your dog does eat a mask.

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Climate change

Climate change drives vegetation gains in patches of the high Arctic tundra.

Parts of the treeless Arctic tundra have become greener as rising temperatures stimulate plant growth.

Low-resolution satellite imagery and some observations made on the ground have suggested that the Arctic tundra, an often-frozen landscape dotted with hardy small plants, has become greener since the 1980s. Now, Logan Berner at Northern Arizona University in Flagstaff and his colleagues have analysed high-resolution images from the Landsat Earth-observing satellites.

The team found that between 1985 and 2016, 37% of the Arctic tundra, including parts of western Eurasia and North America, grew substantially greener. And since the turn of the century, the highest latitudes have experienced the most intense greening.

Temperature records show that the Arctic air and soil grew warmer in summer, on average, over the study period. However, most areas did not become greener. And about 5% of the area studied became browner rather than greener.

Changes in Arctic vegetation affect how carbon cycles through the soil and atmosphere, how wildlife and people make use of the landscape, and how vulnerable the tundra is to wildfires.

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