Seal Whisker Geometry Could Inspire Stronger Underwater Structures

<section class="entry-content instapaper_body clearfix" itemprop="articleBody">
<div class="add-container clearfix" id="add-block-placer">
</div>

 Turbine blades as silent as owl wings. Smartphone displays as vibrant as butterfly scales. Drones as maneuverable as bats.
 

 Nature has solved most engineering problems at one point or another, and studying these solutions can improve technologies and provide us with new ones. The most famous of these is Velcro—wildly useful, worth over $1 billion, and inspired by sticky burdock seeds—but the ideas keep coming. Research published by Cleveland, Ohio, engineers this month explains how a seal’s whiskers could teach us how to build bridge struts and oil wells that last longer underwater.
 

 “There’s a lot that we can learn if we just take a moment to look at nature,” said Aidan Rinehart, an author of the Cleveland University paper. Rinehart is a classically trained engineer, but as a student he attended a lecture about building jet engine blades textured like whale skin and decided to pursue biologically inspired design. Now Rinehart is figuring out how seals manage to detect predators and prey with their whiskers while neatly avoiding problems that plague our own underwater technology.
 
<figure class="richtext-image full-width">
<img alt="" class="richtext-image full-width" src="https://www.pbs.org/wgbh/nova/media/images/harbor-seal_2048x1152.width-990_gyQjZEq.jpg"/>
<figcaption>Seals have undulating whiskers that allow them to hunt even when blindfolded and ear-muffed.
 
 </figcaption>
</figure>

 When water flows around an irregular structure, it forms a lazy zigzag wake that makes the structure rattle. These vibrations damage almost everything we put in the water, from the columns of wind turbines to the risers on oil rigs, and they cost us a fortune—British Petroleum estimates that countering the damage eats up 10% of their multi-billion dollar budget for deep-sea projects.
 

 A seal’s underwater acrobatics should cause its whiskers to vibrate so intensely that outside disturbances would be undetectable, but they don’t. If we understood why, we might be able to build underwater structures that work better and last longer.
 

 A seal whisker is shaped like a ripe bean-pod—a slightly flattened cylinder with smooth, regular bulges up and down the length. If you sliced it in two at the center of a bulge, the cross-section would be an ellipse; if you sliced it at a narrow place the cross-section would be a circle. The current theory is that these undulations each make their own small wake, instead of the single, powerful wake left by smooth whisker. Not only are the smaller wakes weaker, but they go in all different directions, so they can’t align to move the whisker. Sea lions, which have smooth whiskers, can’t navigate with their whiskers alone, but seals with undulating whiskers can hunt even when blindfolded and ear-muffed by researchers.
 

 By holding its whiskers perfectly steady, the seal can detect tiny swirls of turbulence that would otherwise be invisible. As a fish swims, a defined current unfolds in its wake, undulating through the water like a cracked whip. To a seal, this trail is as easy to follow as the track a snake leaves in the dust. “It’s like a signature,” said MIT’s Michael Triantafyllou. “They can tell what it is at a distance.”
 

 Triantafyllou is one of the pioneers of biologically-inspired marine engineering, and Rinehart cites his work both in his recent paper and in conversation. Research by Triantafyllou, Rinehart, and many others supports the idea that the undulations in seal whiskers are the key to their remarkable stability, but that wasn’t enough information to start building multi-million dollar bridges and drilling platforms. Rinehart’s recent paper focuses on finding the exact parameters of the whisker so they can be applied to human technologies—the kind of fiddly measurement work that is vital, but not usually very exciting.
 

 But Rinehart found something thrilling in his measurements. The proportions of the whisker, produced by millions of years of natural selection, were precisely what several different groups of engineers had calculated to be ideal for reducing vibration. Evolution and human problem solving had collided at the same solution.
 

 “There’s this small aspect of this really complex geometry that’s found in nature, and it just so happens to match—it’s dumfounding,” Rinehart said. “There’s some really amazing things happening in nature, and we don’t even really know most of the time.”
 

 “The ideas never stop coming,” Triantafyllou said. “The question is not whether there are such applications, it’s whether we have the knowledge and understanding to do something about it.”
 
</section>

 Photo credit:
 <a href="https://commons.wikimedia.org/wiki/File:Seehund.jpg">
 Marcel Burkhard / Wikimedia Commons (CC BY-SA 2.0 DE)
 </a>

Pacemakers Fail More Often Than Manufacturers Acknowledge

<section class="entry-content instapaper_body clearfix" itemprop="articleBody">
<div class="add-container clearfix" id="add-block-placer">
</div>

 Pacemakers and implantable defibrillators malfunction far more often than manufacturers acknowledge, according to ongoing research in California.
 

 Zian Tseng, a physician who researches cardiac devices at the University of California, San Francisco, realized as far back as 2006 that he wouldn’t necessarily know if the pacemakers and defibrillators he implanted in his patients failed. When a person with heart disease dies of a heart attack, it’s rare for anyone to look deeply into the cause. “It’s really the medical examiners that see those cases, the coroners,” Tseng said. “But the problem is that coroners and medical examiners often are busy with legal cases. The natural deaths almost never get investigated.”
 
<figure class="richtext-image full-width">
<img alt="" class="richtext-image full-width" src="https://www.pbs.org/wgbh/nova/media/images/878px-pacemaker.width-990_1FtnpLm.jpg"/>
<figcaption>There’s a wide range of reasons why a cardiac device could malfunction—from drained batteries to serious mechanical failures.
 
 </figcaption>
</figure>

 So Tseng decided to investigate heart attacks as thoroughly as medical examiners investigate murders. For 35 months, he and his team tracked down everyone who died suddenly in San Francisco County, regardless of the cause. If the person’s body had a cardiac device, the team removed it for examination and performed an autopsy to identify the cause of death.
 

 The results the team published in 2015 stunned Tseng: Half of the cardiac devices had some kind of defect, ranging from drained batteries to serious mechanical failures. Among defibrillator patients, 6.4% of those who died suddenly had a problem with their device.
 

 Tseng quickly realized that cardiac devices could be malfunctioning much more often than the manufacturers indicated. “If you do a back-of-the-envelope calculation on the rates of failure based upon the overall pool of devices out there, it’s orders of magnitude higher than the device companies publish,” Tseng said. So he approached three major manufacturers—St. Jude Medical, Medtronic, and Boston Scientific—to tell them what he’d found.
 

 “When I went to each of these device companies, I got a range of responses from ‘Wow, this could really help our [quality control] processes’ to outright abject denial that these were even issues,” Tseng said.
 

 Tseng found Medtronic the most receptive of the companies he contacted. According to Tracy McNulty, a Medtronic spokeswoman, they offered Tseng technical support to continue his research. Medtronic was the only one of the three companies that agreed to comment for this story.
 

 Tseng says that St. Jude Medical listened to what he had to say, but was less enthusiastic than Medtronic. A St. Jude spokesman initially responded to a request for comment, but did not provide one before press time.
 

 Tseng says he and his research got a cold greeting at Boston Scientific. The company did not respond to repeated requests for comment. “They didn’t want a collaborator, let’s put it that way,” Tseng said. “That was the least constructive response.”
 

 Manufacturers aren’t the only ones responsible for keeping tabs on medical devices. Once devices have been released into the market, the Food &amp; Drug Administration (FDA) is in charge of making sure they’re as safe and effective as clinical trials indicated. If a doctor thinks her patient has been hurt or killed by a device problem, she can report it to the FDA. “There are two flaws with that,” Tseng said. “Number one, it’s voluntary. Number two, we only see the people who make it to the clinic, who are by definition alive.”
 

 Joseph Ross, a Yale cardiologist who studies health-care delivery, agrees. “The way we are able to monitor medical devices…is quite limited, actually,” Ross said. That’s partly due to the lack of data. When a patient is given a medication, the exact drug and dose are reported to whoever ends up footing the bill. But when a patient gets a medical device, the bill is for the implantation surgery. There’s no record of what brand of device the patient got, and no way to track down a specific device in the future.
 

 “The FDA recognizes limitations in its current medical device post market surveillance,” said FDA spokeswoman Stephanie Caccomo. She also said that the FDA is pursuing “big data” solutions to reveal patterns more quickly.
 

 Better analysis would do a lot of good for the FDA database, which Ross called “a black file of data.” But it won’t change the fact that fatal problems are hardly ever reported to begin with because natural deaths are so rarely investigated.
 

 That’s why Zian Tseng has continued to learn from the dead. His new data, released later this year, will be welcomed by researchers who have spent years trying to study device failure using the tiny handful of published cases. As Ross put it, “that’s a tip-of-the-iceberg type of signal.”
 
</section>

 Photo credit:
 <a href="https://commons.wikimedia.org/wiki/File:Pacemaker.jpg">
 Lucien Monfils / Wikimedia Commons (CC BY-SA 3.0)
 </a>

This Test Could Give Cancer Patients a More Personalized Prognosis

<section class="entry-content instapaper_body clearfix" itemprop="articleBody">
<div class="add-container clearfix" id="add-block-placer">
</div>

 Adam Hayden was wide awake as the neurosurgeon pried a coin-sized piece of bone from his skull, exposing both his brain in its clear sac and a tumor the size of a plum. The neurosurgeon removed the tumor in pieces, sealing them in a freezer colder than the surface of Mars until a pathologist could confirm their identity: a deadly brain cancer called glioblastoma. Eventually the surgeon reached a point where he could go no deeper without cutting healthy tissue. Stopping meant some cancer would remain. But if he kept cutting, Hayden would likely be paralyzed on the left side of his body. No one could make the choice but Hayden. He was glad to be awake for it.
 

 The prognosis for glioblastoma is grim. Two years after diagnosis, just 30% of patients are still alive. After five years, it’s 3%. But patients still have to decide how they’ll be treated, and all of them currently use crude survival estimates like the ones above. That’s not good enough for Jill Barnholtz-Sloan and her colleagues, who recently published a glioblastoma nomogram—a statistical tool that synthesizes test results into an individual prediction.
 
<figure class="richtext-image full-width">
<img alt="" class="richtext-image full-width" src="https://www.pbs.org/wgbh/nova/media/images/glioblastoma_multiforme_1024x576.width-990_SC0uxlD.jpg"/>
<figcaption>A typical untreated brain with glioblastoma
 
 </figcaption>
</figure>

 “The easiest statistic to quote is the median survival,” said Barnholtz-Sloan, a cancer epidemiologist at Case Western Reserve. “But we all know two things. One, not everyone is the median, and two, every patient wants to think that they’re going to be the patient with exceptional survival.” Nomograms tackle both problems.
 

 On the surface, a nomogram is a series of questions about you and your tumor. As you answer questions, you accumulate points, and the point total is converted into your likelihood of having a particular outcome. The backbone of the nomogram is a set of equations which determine how many points to assign each answer.
 

 Though nomograms offer patients better information about their potential outcomes, getting clinicians to adopt them has been a challenge, said Michael Kattan, the Chairman of Quantitative Health Sciences at the Cleveland Clinic. Kattan’s prostate cancer nomograms are widely used today, but he doesn’t think that would be the case if not for his collaborator Peter Scardino, a surgeon who, in Kattan’s words, “spread the Gospel” about nomograms to other doctors.
 

 Kattan met Scardino while both men were working at Baylor College of Medicine. “I’d hear him and the others talk about how they really wanted to counsel patients better,” Kattan said. “And I could see the way they were putting the pieces together and just be thinking, ‘that’s not really the best way to do it.’” So Kattan roughed out a prostate cancer nomogram for Scardino.
 

 The nomogram revealed staggering problems. “We’re telling these patients they’re high-risk. and they’re actually low. And we’re telling these patients they’re low-risk, and they’re actually high,” Kattan remembers telling Scardino. “We’re just making mistakes right and left by doing it that way.”
 

 Kattan didn’t plan to go into medicine. He was working on a PhD in management information systems when he learned he had advanced Hodgkin lymphoma, a cancer of the immune system. After two months of chemotherapy, Kattan faced a decision: whether to undergo radiation. Radiation would destroy any lingering cancer cells in his bone marrow, but it might damage his heart permanently. The risk estimates his doctor gave him were too broad—they were for populations, not an individual. He chose the radiation.
 

 Hayden points out that this problem comes up all the time, most famously when women who are genetically predisposed to breast cancer decide whether or not to get mastectomies. “That is a life-altering decision based on statistical information,” Hayden said. “I think what we need is more sophisticated statistics.” He could just as easily be talking about Kattan, or himself.
 

 More sophisticated statistics, like Barnholtz-Sloan’s new nomogram, might easily have helped Hayden as he weighed the relative disadvantages of paralysis and death. But his surgeon had another method of reducing uncertainty. He told Hayden to just ignore the future and decide based on his “quality of life today.”
 

 “That sort of set off the lightbulb,” Hayden said. Today, he could chase his toddlers around the yard. Today he could play hide-and-seek. He told the surgeon to stop. “I said…Let’s preserve the function that I have. And I would make that decision exactly the same, over and over and over and over.”
 
</section>

 Photo credit:
 <a href="https://commons.wikimedia.org/wiki/File:Glioblastoma_multiforme.jpg">
 PEIR Digital Library (Pathology image database) / Wikimedia Commons
 </a>

Lydia-Rose Kesich

Articles

Seal Whisker Geometry Could Inspire Stronger Underwater Structures

Pacemakers Fail More Often Than Manufacturers Acknowledge

This Test Could Give Cancer Patients a More Personalized Prognosis

Support Provided By