Stanford University
Stanford University

How a Child’s Toy Inspired a Super-Cheap Paper Centrifuge

Stanford University
Stanford University

Scientists at Stanford University have built a super-cheap, super-fast centrifuge out of everyday items. Their inspiration? A simple spinning toy. The team described their invention in the journal Nature Biomedical Engineering.

Biophysicist Manu Prakash is on a quest to make scientific and medical equipment cheaper and more accessible for everyone. He’s developed parasite-detecting skin patches and computers that run on drops of water. Last year, he made a splash with the introduction of the Foldoscope—an inexpensive, DIY paper microscope that users can assemble themselves. His goal is to distribute 1 million to schools worldwide by the end of 2017. 

For his next trick, Prakash turned his attention to the centrifuge, a machine that spins rapidly to separate blood samples into their component parts. Centrifuging is a basic and crucial element of conducting blood tests like the one for malaria, yet many clinics around the world either cannot afford a machine or don’t have access to the electricity required to power it. “I realized that if we wanted to solve a critical problem like malaria diagnosis,” Prakash said in a statement, “we needed to design a human-powered centrifuge that costs less than a cup of coffee.”

He brought the problem back to his lab and began brainstorming with postdoctoral research fellow Saad Bhamla. They realized that the centrifuge’s primary job is simply to spin—the same job shared by thousands of years of children’s toys. They brought in armloads of old toys and pieces and set to work playing with them.

One evening, Prakash was spinning a simple whirligig device that he’d made from a button and some string. He decided to set up a high-speed camera to see how fast the thing could go. When he checked the tape, he was amazed. The crude setup was powerful enough to get the button spinning 10,000 to 15,000 times per minute.

The next step was rigging the center disk to hold and process samples. After a few weeks of experimentation, Prakash had his prototype: a paper disk loaded with thin tubes of blood.

Not content to let it rest there, he and Bhamla recruited a team of mathematicians and asked them to optimize the new paper machine. “We realized that this is a toy that no one had thought about,” he told The Atlantic. “The physics of how it works weren’t understood, and its fundamental limits were completely unknown. So we spent six months thinking about the math, all with the goal of asking how fast it could really go.”

The answer: a staggering 125,000 revolutions per minute—which the team believes is the fastest rotational speed ever recorded for a human-powered object. (“We have submitted an application to Guinness World Records,” they note in the paper.) This “paperfuge,” as they call it, can separate liquid blood from plasma in just two minutes. In 15 minutes, it can extract malaria parasites from a drop of blood.

This exceptional speed is just part of the paperfuge’s appeal. The rest comes in its dirt-cheap construction. The final prototype is made out of waterproof paper, Velcro, drinking straws, and fishing line. It weighs less than 2 grams and can be produced for about 20 cents. And this, Prakash says, is the key: “Frugal science is about democratizing scientific tools to get them out to people around the world.”

Charles Dickens Museum Highlights the Author's Contributions to Science and Medicine

Charles Dickens is celebrated for his verbose prose and memorable opening lines, but lesser known are his contributions to science—particularly the field of medicine.

A new exhibition at London’s Charles Dickens Museum—titled "Charles Dickens: Man of Science"—is showcasing the English author’s scientific side. In several instances, the writer's detailed descriptions of medical conditions predated and sometimes even inspired the discovery of several diseases, The Guardian reports.

In his novel Dombey and Son, the character of Mrs. Skewton was paralyzed on her right side and unable to speak. Dickens was the first person to document this inexplicable condition, and a scientist later discovered that one side of the brain was largely responsible for speech production. "Fat boy" Joe, a character in The Pickwick Papers who snored loudly while sleeping, later lent his namesake to Pickwickian Syndrome, otherwise known as obesity hypoventilation syndrome.

A figurine of Fat Boy Joe
Courtesy of the Charles Dickens Museum

Dickens also wrote eloquently about the symptoms of tuberculosis and dyslexia, and some of his passages were used to teach diagnosis to students of medicine.

“Dickens is an unbelievably acute observer of human behaviors,” museum curator Frankie Kubicki told The Guardian. “He captures these behaviors so perfectly that his descriptions can be used to build relationships between symptoms and disease.”

Dickens was also chummy with some of the leading scientists of his day, including Michael Faraday, Charles Darwin, and chemist Jane Marcet, and the exhibition showcases some of the writer's correspondence with these notable figures. Beyond medicine, Dickens also contributed to the fields of chemistry, geology, and environmental science.

Less scientifically sound was the author’s affinity for mesmerism, a form of hypnotism introduced in the 1770s as a method of controlling “animal magnetism,” a magnetic fluid which proponents of the practice believed flowed through all people. Dickens studied the methods of mesmerism and was so convinced by his powers that he later wrote, “I have the perfect conviction that I could magnetize a frying-pan.” A playbill of Animal Magnetism, an 1857 production that Dickens starred in, is also part of the exhibit.

A play script from Animal Magnetism
Courtesy of the Charles Dickens Museum

Located at 48-49 Doughty Street in London, the exhibition will be on display until November 11, 2018.

[h/t The Guardian]

Feeling Down? Lifting Weights Can Lift Your Mood, Too

There’s plenty of research that suggests that exercise can be an effective treatment for depression. In some cases of depression, in fact—particularly less-severe ones—scientists have found that exercise can be as effective as antidepressants, which don’t work for everyone and can come with some annoying side effects. Previous studies have largely concentrated on aerobic exercise, like running, but new research shows that weight lifting can be a useful depression treatment, too.

The study in JAMA Psychiatry, led by sports scientists at the University of Limerick in Ireland, examined the results of 33 previous clinical trials that analyzed a total of 1877 participants. It found that resistance training—lifting weights, using resistance bands, doing push ups, and any other exercises targeted at strengthening muscles rather than increasing heart rate—significantly reduced symptoms of depression.

This held true regardless of how healthy people were overall, how much of the exercises they were assigned to do, or how much stronger they got as a result. While the effect wasn’t as strong in blinded trials—where the assessors don’t know who is in the control group and who isn’t, as is the case in higher-quality studies—it was still notable. According to first author Brett Gordon, these trials showed a medium effect, while others showed a large effect, but both were statistically significant.

The studies in the paper all looked at the effects of these training regimes on people with mild to moderate depression, and the results might not translate to people with severe depression. Unfortunately, many of the studies analyzed didn’t include information on whether or not the patients were taking antidepressants, so the researchers weren’t able to determine what role medications might play in this. However, Gordon tells Mental Floss in an email that “the available evidence supports that [resistance training] may be an effective alternative and/or adjuvant therapy for depressive symptoms that could be prescribed on its own and/or in conjunction with other depression treatments,” like therapy or medication.

There haven’t been a lot of studies yet comparing whether aerobic exercise or resistance training might be better at alleviating depressive symptoms, and future research might tackle that question. Even if one does turn out to be better than the other, though, it seems that just getting to the gym can make a big difference.


More from mental floss studios