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Toward a disease-sniffing device that rivals a dog’s nose
Trained dogs can detect cancer and other diseases by smell. Could a device do the same?
Numerous studies have shown that trained dogs can detect many kinds of disease — including lung, breast, ovarian, bladder, and prostate cancers, and possibly Covid-19 — simply through smell. In some cases, involving prostate cancer for example, the dogs had a 99 percent success rate in detecting the disease by sniffing patients' urine samples.
But it takes time to train such dogs, and their availability and time is limited. Scientists have been hunting for ways of automating the amazing olfactory capabilities of the canine nose and brain, in a compact device. Now, a team of researchers at MIT and other institutions has come up with a system that can detect the chemical and microbial content of an air sample with even greater sensitivity than a dog's nose. They coupled this to a machine-learning process that can identify the distinctive characteristics of the disease-bearing samples.
The findings, which the researchers say could someday lead to an automated odor-detection system small enough to be incorporated into a cellphone, are being published today in the journal PLOS One, in a paper by Claire Guest of Medical Detection Dogs in the U.K., Research Scientist Andreas Mershin of MIT, and 18 others at Johns Hopkins University, the Prostate Cancer Foundation, and several other universities and organizations.
“Dogs, for now 15 years or so, have been shown to be the earliest, most accurate disease detectors for anything that we've ever tried," Mershin says. And their performance in controlled tests has in some cases exceeded that of the best current lab tests, he says. “So far, many different types of cancer have been detected earlier by dogs than any other technology."
What's more, the dogs apparently pick up connections that have so far eluded human researchers: When trained to respond to samples from patients with one type of cancer, some dogs have then identified several other types of cancer — even though the similarities between the samples weren't evident to humans.
These dogs can identify "cancers that don't have any identical biomolecular signatures in common, nothing in the odorants," Mershin says. Using powerful analytical tools including gas chromatography mass spectrometry (GCMS) and microbial profiling, "if you analyze the samples from, let's say, skin cancer and bladder cancer and breast cancer and lung cancer — all things that the dog has been shown to be able to detect — they have nothing in common." Yet the dog can somehow generalize from one kind of cancer to be able to identify the others.
Mershin and the team over the last few years have developed, and continued to improve on, a miniaturized detector system that incorporates mammalian olfactory receptors stabilized to act as sensors, whose data streams can be handled in real-time by a typical smartphone's capabilities. He envisions a day when every phone will have a scent detector built in, just as cameras are now ubiquitous in phones. Such detectors, equipped with advanced algorithms developed through machine learning, could potentially pick up early signs of disease far sooner than typical screening regimes, he says — and could even warn of smoke or a gas leak as well.
In the latest tests, the team tested 50 samples of urine from confirmed cases of prostate cancer and controls known to be free of the disease, using both dogs trained and handled by Medical Detection Dogs in the U.K. and the miniaturized detection system. They then applied a machine-learning program to tease out any similarities and differences between the samples that could help the sensor-based system to identify the disease. In testing the same samples, the artificial system was able to match the success rates of the dogs, with both methods scoring more than 70 percent.
The miniaturized detection system, Mershin says, is actually 200 times more sensitive than a dog's nose in terms of being able to detect and identify tiny traces of different molecules, as confirmed through controlled tests mandated by DARPA. But in terms of interpreting those molecules, "it's 100 percent dumber." That's where the machine learning comes in, to try to find the elusive patterns that dogs can infer from the scent, but humans haven't been able to grasp from a chemical analysis.
"The dogs don't know any chemistry," Mershin says. "They don't see a list of molecules appear in their head. When you smell a cup of coffee, you don't see a list of names and concentrations, you feel an integrated sensation. That sensation of scent character is what the dogs can mine."
While the physical apparatus for detecting and analyzing the molecules in air has been under development for several years, with much of the focus on reducing its size, until now the analysis was lacking. "We knew that the sensors are already better than what the dogs can do in terms of the limit of detection, but what we haven't shown before is that we can train an artificial intelligence to mimic the dogs," he says. "And now we've shown that we can do this. We've shown that what the dog does can be replicated to a certain extent."
This achievement, the researchers say, provides a solid framework for further research to develop the technology to a level suitable for clinical use. Mershin hopes to be able to test a far larger set of samples, perhaps 5,000, to pinpoint in greater detail the significant indicators of disease. But such testing doesn't come cheap: It costs about $1,000 per sample for clinically tested and certified samples of disease-carrying and disease-free urine to be collected, documented, shipped, and analyzed he says.
Reflecting on how he became involved in this research, Mershin recalled a study of bladder cancer detection, in which a dog kept misidentifying one member of the control group as being positive for the disease, even though he had been specifically selected based on hospital tests as being disease free. The patient, who knew about the dog's test, opted to have further tests, and a few months later was found to have the disease at a very early stage. "Even though it's just one case, I have to admit that did sway me," Mershin says.
The team included researchers at MIT, Johns Hopkins University in Maryland, Medical Detection Dogs in Milton Keynes, U.K., the Cambridge Polymer Group, the Prostate Cancer Foundation, the University of Texas at El Paso, Imagination Engines, and Harvard University. The research was supported by the Prostate Cancer Foundation, the National Cancer Institute, and the National Institutes of Health.
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A new paper reveals that the Voyager 1 spacecraft detected a constant hum coming from outside our Solar System.
- Voyager 1, humankind's most distant space probe, detected an unusual "hum" in the data from interstellar space.
- The noise is likely produced by interstellar gas.
- Further investigation may reveal the hum's exact origins.
Voyager 1, humanity's most faraway spacecraft, has detected an unusual "hum" coming from outside our solar system. Fourteen billion miles away from Earth, the Voyager's instruments picked up a droning sound that may be caused by plasma (ionized gas) in the vast emptiness of interstellar space. Launched in 1977, the Voyager 1 space probe — along with its twin Voyager 2 — has been traveling farther and farther into space for over 44 years. It has now breached the edge of our solar system, exiting the heliosphere, the bubble-like region of space influenced by the sun. Now, the spacecraft is moving through the "interstellar medium," where it recorded the peculiar sound.
Stella Koch Ocker, a doctoral student in astronomy at Cornell University, discovered the sound in the data from the Voyager's Plasma Wave System (PWS), which measures electron density. Ocker called the drone coming from plasma shock waves "very faint and monotone," likely due to the narrow bandwidth of its frequency.
While they think the persistent background hum may be coming from interstellar gas, the researchers don't yet know what exactly is causing it. It might be produced by "thermally excited plasma oscillations and quasi-thermal noise."
The new paper from Ocker and her colleagues at Cornell University and the University of Iowa, published in Nature Astronomy, also proposes that this is not the last we'll hear of the strange noise. The scientists write that "the emission's persistence suggests that Voyager 1 may be able to continue tracking the interstellar plasma density in the absence of shock-generated plasma oscillation events."
Voyager Captures Sounds of Interstellar Space www.youtube.com
The researchers think the droning sound may hold clues to how interstellar space and the heliopause, which can be thought of as the solar's system border, may be affecting each other. When it first entered interstellar space, the PWS instrument reported disturbances in the gas caused by the sun. But in between such eruptions is where the researchers spotted the steady signature made by the near-vacuum.
Senior author James Cordes, a professor of astronomy at Cornell, compared the interstellar medium to "a quiet or gentle rain," adding that "in the case of a solar outburst, it's like detecting a lightning burst in a thunderstorm and then it's back to a gentle rain."
More data from Voyager over the next few years may hold crucial information to the origins of the hum. The findings are already remarkable considering the space probe is functioning on technology from the mid-1970s. The craft has about 70 kilobytes of computer memory. It also carries a Golden Record created by a committee chaired by the late Carl Sagan, who taught at Cornell University. The 12-inch gold-plated copper disk record is essentially a time capsule, meant to tell the story of Earthlings to extraterrestrials. It contains sounds and images that showcase the diversity of Earth's life and culture.
As the American population grows, fewer people will die of cancer.
- A new study projects that cancer deaths will decrease in relative and absolute terms by 2040.
- The biggest decrease will be among lung cancer deaths, which are predicted to fall by 50 percent.
- Cancer is like terrorism: we cannot eliminate it entirely, but we can minimize its influence.
As the #2 leading cause of death, cancer takes the lives of about 600,000 Americans each year. In comparison, heart disease (#1) claims more than 650,000 lives, while accidents (#3) take about 175,000 lives. (In 2020 and likely 2021, COVID will claim the #3 spot.)
Headlines are usually full of terrible news about cancer. Seemingly, you can't get away from anything that causes it. RealClearScience made a list of all the things blamed for cancer — antiperspirants, salty soup, eggs, corn, Pringles, bras, burnt toast, and even Facebook made the list.
The reality, however, is much more optimistic. We're slowly but surely winning the war on cancer.
Winning the war on cancer
How can we make such a brazen statement? A new paper published in the journal JAMA Network Open tracks trends in cancer incidence and deaths and makes projections to the year 2040. The authors predict that around 568,000 Americans will have died of cancer in 2020, but they project that number to fall to 410,000 by 2040. That's a drop of nearly 28 percent, despite the U.S. population being projected to grow from roughly 333 million today to 374 million in 2040, an increase of 12 percent. That means cancer deaths will decrease in both relative and absolute terms.
What accounts for this unexpected good news? The lion's share is the number of deaths attributable to lung cancer, which is projected to decrease by more than 50 percent, from 130,000 to 63,000. This drop is largely due to the decreasing use of tobacco products. Other deaths predicted to decline include those from colorectal, breast, prostate, and ovarian cancers, among others, such as leukemia and non-Hodgkin lymphoma (NHL).
The authors credit screening and biomedical advances for saving many of these lives. For instance, lead author Dr. Lola Rahib wrote in an email to Big Think that "colonoscopies remove precancerous polyps." She also noted that targeted therapies and immunotherapies have helped reduce the number of deaths from leukemia and NHL.
We'll never cure cancer
Now the bad news: We'll never cure cancer. There are at least three reasons for this. The first is obvious: We all die. The lifetime prevalence of death is 100 percent. The truth is that we are running out of things to die from. After a long enough period of time, something gives out — often your cardiovascular system or nervous system. Or you develop you cancer.
The second reason is that we are multicellular organisms and, hence, we are susceptible to cancer. (Contrary to popular myth, sharks get cancer, too.) The cells of multicellular organisms face an existential dilemma: they can either get old and stop dividing (a process called senescence) or become immortal but cancerous. For this reason, the problem of cancer may not have a solution.
Finally, there isn't really such a thing as a disease called "cancer." What we call cancer is actually a collection of several different diseases, some of which are preventable (like cervical cancer with the HPV vaccine) or curable (like prostate cancer). Unfortunately, some cancers probably never will be curable, not least because cancers can mutate and develop resistance to the drugs we use to treat them.
But the overall optimism still stands: We are slowly and incrementally winning the war on cancer. Like terrorism, it's not a foe that we can completely vanquish, but it is one whose influence we can minimize in our lives.
China has reached a new record for nuclear fusion at 120 million degrees Celsius.
This article was originally published on our sister site, Freethink.
China wants to build a mini-star on Earth and house it in a reactor. Many teams across the globe have this same bold goal --- which would create unlimited clean energy via nuclear fusion.
But according to Chinese state media, New Atlas reports, the team at the Experimental Advanced Superconducting Tokamak (EAST) has set a new world record: temperatures of 120 million degrees Celsius for 101 seconds.
Yeah, that's hot. So what? Nuclear fusion reactions require an insane amount of heat and pressure --- a temperature environment similar to the sun, which is approximately 150 million degrees C.
If scientists can essentially build a sun on Earth, they can create endless energy by mimicking how the sun does it.
If scientists can essentially build a sun on Earth, they can create endless energy by mimicking how the sun does it. In nuclear fusion, the extreme heat and pressure create a plasma. Then, within that plasma, two or more hydrogen nuclei crash together, merge into a heavier atom, and release a ton of energy in the process.
Nuclear fusion milestones: The team at EAST built a giant metal torus (similar in shape to a giant donut) with a series of magnetic coils. The coils hold hot plasma where the reactions occur. They've reached many milestones along the way.
According to New Atlas, in 2016, the scientists at EAST could heat hydrogen plasma to roughly 50 million degrees C for 102 seconds. Two years later, they reached 100 million degrees for 10 seconds.
The temperatures are impressive, but the short reaction times, and lack of pressure are another obstacle. Fusion is simple for the sun, because stars are massive and gravity provides even pressure all over the surface. The pressure squeezes hydrogen gas in the sun's core so immensely that several nuclei combine to form one atom, releasing energy.
But on Earth, we have to supply all of the pressure to keep the reaction going, and it has to be perfectly even. It's hard to do this for any length of time, and it uses a ton of energy. So the reactions usually fizzle out in minutes or seconds.
Still, the latest record of 120 million degrees and 101 seconds is one more step toward sustaining longer and hotter reactions.
Why does this matter? No one denies that humankind needs a clean, unlimited source of energy.
We all recognize that oil and gas are limited resources. But even wind and solar power --- renewable energies --- are fundamentally limited. They are dependent upon a breezy day or a cloudless sky, which we can't always count on.
Nuclear fusion is clean, safe, and environmentally sustainable --- its fuel is a nearly limitless resource since it is simply hydrogen (which can be easily made from water).
With each new milestone, we are creeping closer and closer to a breakthrough for unlimited, clean energy.