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We've "Outsmarted" Nature’s Cycles—And It's Disrupting Our Mental Health
A "new" field of medicine called chronotherapy demonstrates that following nature's cycles, as our ancestors did, is integral to proper biological and cognitive function.
Every technological advance has detrimental effects. Two in particular have become relevant when contemplating a variety of ailments, from cancer and heart attacks to depression and mental illness: the light bulb and airplane. Though the benefits of both are innumerable, growing research on circadian rhythms is forcing us to question our habits as emerging therapeutic interventions are being used to combat the unexpected ravages of constant artificial light and the reality of time zones.
Chronobiology is the study of cycles. All life depends on biological clocks; animals and plants adapt to periods of light and dark. In our triumph over nature’s cycles, humans have disrupted the rhythms of biological functioning, which may be at the root of many physiological and cognitive diseases. Researchers now wonder if getting back on track with life as nature intended is a silver bullet or if the simple technology of an eye mask and paying closer attention to your sleep cycles are overrated.
The three major circadian cycles are diurnal, representing organisms active during the day, nocturnal, nighttime creatures, and crepuscular, those animals that eat and frolic at dawn and dusk. These cycles are critical in eating, mating, sleeping, migration, and cellular regeneration in animals. The field of chronobiology kicked off in 1960, borrowing from flora pioneers Jean-Jacques d’Ortous de Mairan and Carl Linnaeus and applying the concept to microbial and animal life.
This diagram depicts the circadian patterns typical of someone who rises early in morning, eats lunch around noon, and sleeps at night (10p.m.). Data sourced from The Body Clock Guide to Better Health by Michael Smolensky and Lynne Lamberg.
More recently the circadian phenomenon has been used to study jet lag. One study at a psychiatric hospital near London’s Heathrow Airport discovered that patients who had traveled from the west showed an increase in mania, while those who traveled from the east suffered higher rates of depression. Years later an Italian psychiatrist noticed patients whose windows faced east were discharged sooner than those who were assigned west-facing rooms.
The combination of light and melatonin appears to be the culprit in symptoms of jet lag, which can also be applied to sleeping disorders (or to people who, out of habit or employment, develop unnatural sleeping patterns). Your brain begins secreting melatonin a few hours before darkness, preparing you for rest. Disrupt that cycle and your body’s clock is thrown off, accompanied by a series of dangerous consequences.
One current intervention for depression is wake therapy, which has been shown to lower depression in those suffering from bipolar disorder and major depression. You wake up halfway through a normal sleep cycle, which changes your body temperature and cortisol levels. When combined with early morning light therapy and ‘sleep phase advance’ (going to bed five to six hours before your normal bedtime), you have ‘triple chronotherapy.’ The results have been positive:
In one study of 60 hospitalized patients with bipolar depression who were taking antidepressants or lithium, 70 percent of those who did not have a history of drug resistance improved rapidly with sleep deprivation and early morning light, and 57 percent remained well after nine months. Encouragingly, 44 percent of patients who had failed to respond to at least one trial of anti-depressants also improved.
Chronotherapy is a response to environmental detachment. Before alarm clocks and light bulbs the sun was dependable timetable. Just because we’ve created our own rhythms does not mean we’re healthier. In fact, the opposite is likely true. As science writer Jessa Gamble writes:
To be fully integrated with an ecosystem, an organism must cling to its niches, and one of those is a carefully carved-out temporal niche.
She goes on to note that different species can occupy the same space if their internal clocks are wound differently. While our modern environment provides constant access to “food, warmth, and light … that desynchrony is causing all manner of problems … just about everything our body does – from metabolism and DNA repair to immune responses and cognition – is under circadian control.”
Our brain’s suprachaistmatic nucleus in the hypothalamus is our body’s master clock, while each organ maintains its own rhythm. Photoreceptors in our retinas inform the clocks as to which alarm should be going off and which remains on snooze. The light we need to accomplish this is daylight. Not all internal clocks are light-dependent—Gamble writes that our liver and pancreas clocks are reset when eating late at night—but when we sleep and frolic do matter to our overall health.
Microbiomes and diseases also have their own rhythm, which is why Gamble writes that paying attention to our circadian rhythm might play an important role in combating disease:
We can pinpoint the timing of our interventions for just the moment when our pathogens are most vulnerable. No longer bathing the body in drugs throughout the day, ‘chronotherapy’ acts like a guided missile to tackle disease at its most active phase.
Cancerous tumors, she continues, are rhythmic as well. Research in France found that doubling the dose of three cytotoxic drugs for patients with advanced colorectal cancer was safe and effective when following a specific timetable that honors our internal rhythms.
Gamble foresees a future with ‘chrono’ attached to most every form of medicine. This fits squarely into the emerging paradigm of personalized medicine. As technology advances and our phone offers reliable diagnoses, perhaps the day will come when we log on to find out our optimal sleep schedules—even though access to a window will often suffice.
Not to be overly optimistic. Susan Perry co-authored a book on chronotherapy in 1990. While she sees promise in these emerging breakthroughs, she has not seen that much of a forward march to the promises of this therapy. She warns against considering chronotherapy a cure-all:
As with so much medical research, translating those breakthroughs into universally accepted and practical clinical applications has turned out to be much more complicated than originally believed.
In a time long before antibiotics, vaccines, and basic hygiene, humans lived by the rhythms of the sun. While many ancient practices were rightly left behind, following the sun’s arc remains an essential component of our health. This reminds us that some breakthroughs are quite old. We just got too excited by the shiny toys we created to realize their dangers.
Derek's next book, Whole Motion: Training Your Brain and Body For Optimal Health, will be published on 7/4/17 by Carrel/Skyhorse Publishing. He is based in Los Angeles. Stay in touch on Facebook and Twitter.
Evolution proves to be just about as ingenious as Nikola Tesla
- For the first time, scientists developed 3D scans of shark intestines to learn how they digest what they eat.
- The scans reveal an intestinal structure that looks awfully familiar — it looks like a Tesla valve.
- The structure may allow sharks to better survive long breaks between feasts.
Considering how much sharks are feared by humans, it is a bit of a surprise that scientists don't know much about the predators. For example, until recently, sharks were thought to be solitary creatures searching the seas for food on their own. Now it appears that some sharks are quite social.
Another mystery is how these prehistoric swimming and eating machines digest food. Although scientists have made 2D sketches of captured sharks' digestive systems based on dissections, there is a limit to what can be learned in this way. Professor Adam Summers at University of Washington's Friday Harbor Labs says:
"Intestines are so complex, with so many overlapping layers, that dissection destroys the context and connectivity of the tissue. It would be like trying to understand what was reported in a newspaper by taking scissors to a rolled-up copy. The story just won't hang together."
Summers is co-author of a new study that has produced the first 3D scans of a shark's intestines, which turns out to have a strange, corkscrew structure. What's even more bizarre is that it resembles the amazing one-way valve designed by inventor Nikola Tesla in 1920. The research is published in the journal Proceedings of the Royal Society B.
What a 3D model reveals
Video: Pacific spiny dogfish intestine youtu.be
According to the study's lead author Samantha Leigh, "It's high time that some modern technology was used to look at these really amazing spiral intestines of sharks. We developed a new method to digitally scan these tissues and now can look at the soft tissues in such great detail without having to slice into them."
"CT scanning is one of the only ways to understand the shape of shark intestines in three dimensions," adds Summers. The researchers scanned the intestines of nearly three dozen different shark species.
It is believed that sharks go for extended periods — days or even weeks — between big meals. The scans reveal that food passes slowly through the intestine, affording sharks' digestive system the time to fully extract its nutrient value. The researchers hypothesize that such a slow digestive process may also require less energy.
It could be that this slow digestion is more susceptible to back flow given that the momentum of digested food through the tract must be minimal. Perhaps that is why sharks evolved something so similar to a Tesla valve.
What is Tesla's valve doing there?
Above, a Tesla valve. Below, a shark intestine.Credit: Samantha Leigh / California State University, Domi
Tesla's "valvular conduit," or what the world now calls a "Tesla valve," is a one-way valve with no moving parts. Its brilliance is based in fluid dynamics and only now coming to be fully appreciated. Essentially, a series of teardrop-shaped loops arranged along the length of the valve allow water to flow easily in one direction but not in the other. Modern tests reveal that at low flow rates, water can travel through the valve either way, but at high flow rates, the design kicks in. According to mathematician Leif Ristroph:
"Crucially, this turn-on comes with the generation of turbulent flows in the reverse direction, which 'plug' the pipe with vortices and disrupting currents. Moreover, the turbulence appears at far lower flow rates than have ever previously been observed for pipes of more standard shapes — up to 20 times lower speed than conventional turbulence in a cylindrical pipe or tube. This shows the power it has to control flows, which could be used in many applications."
A deeper dive
Summers suggests the scans are just the beginning. "The vast majority of shark species, and the majority of their physiology, are completely unknown," says Summers, adding that "every single natural history observation, internal visualization, and anatomical investigation shows us things we could not have guessed at."
To this end, the researchers plan to use 3D printing to produce models through which they can observe the behavior of different substances passing through them — after all, sharks typically eat fish, invertebrates, mammals, and seagrass. They also plan to explore with engineers ways in which the shark intestine design could be used industrially, perhaps for the treatment of wastewater or for filtering microplastics.
It could fairly be said, though, that Nikola Tesla was 100 years ahead of them.
The non-contact technique could someday be used to lift much heavier objects — maybe even humans.
- Since the 1980s, researchers have been using sound waves to move matter through a technique called acoustic trapping.
- Acoustic trapping devices move bits of matter by emitting strategically designed sound waves, which interact in such a way that the matter becomes "trapped" in areas of particular velocity and pressure.
- Acoustic and optical trapping devices are already used in various fields, including medicine, nanotechnology, and biological research.
Sound can have powerful effects on matter. After all, sound strikes our world in waves — vibrations of air molecules that bounce off of, get absorbed by, or pass through matter around us. Sound waves from a trained opera singer can shatter a wine glass. From a jet, they can collapse a stone wall. But sound can also be harnessed for delicate interactions with matter.
Since the 1980s, researchers have been using sound to move matter through a phenomenon called acoustic trapping. The method is based on the fact that sound waves produce an acoustic radiation force.
"When an acoustic wave interacts with a particle, it exerts both an oscillatory force and a much smaller steady-state 'radiation' force," wrote the American Physical Society. "This latter force is the one used for trapping and manipulation. Radiation forces are generated by the scattering of a traveling sound wave, or by energy gradients within the sound field."
When tiny particles encounter this radiation, they tend to be drawn toward regions of certain pressure and velocity within the sound field. Researchers can exploit this tendency by engineering sound waves that "trap" — or suspend — tiny particles in the air. Devices that do this are often called "acoustic tweezers."
Building a better tweezer
A study recently published in the Japanese Journal of Applied Physics describes how researchers created a new type of acoustic tweezer that was able to lift a small polystyrene ball into the air.
Tweezers of Sound: Acoustic Manipulation off a Reflective Surface youtu.be
It is not the first example of a successful "acoustic tweezer" device, but the new method is likely the first to overcome a common problem in acoustic trapping: sound waves bouncing off reflective surfaces, which disrupts acoustic traps.
To minimize the problems of reflectivity, the team behind the recent study configured ultrasonic transducers such that the sound waves that they produce overlap in a strategic way that is able to lift a small bit of polystyrene from a reflective surface. By changing how the transducers emit sound waves, the team can move the acoustic trap through space, which moves the bit of matter.
Move, but don't touch
So far, the device is only able to move millimeter-sized pieces of matter with varying degrees of success. "When we move a particle, it sometimes scatters away," the team noted. Still, improved acoustic trapping and other no-contact lifting technologies — like optical tweezers, commonly used in medicine — could prove useful in many future applications, including cell separation, nanotechnologies, and biological research.
Could future acoustic-trapping devices lift large and heavy objects, maybe even humans? It seems possible. In 2018, researchers from the University of Bristol managed to acoustically trap particles whose diameters were larger than the sound wavelength, which was a breakthrough because it surpassed "the classical Rayleigh scattering limit that has previously restricted stable acoustic particle trapping," the researchers wrote in their study.
In other words, the technique — which involved suspending matter in tornado-like acoustic traps — showed that it is possible to scale up acoustic trapping.
"Acoustic tractor beams have huge potential in many applications," Bruce Drinkwater, co-author of the 2018 study, said in a statement. "I'm particularly excited by the idea of contactless production lines where delicate objects are assembled without touching them."
Australian parrots have worked out how to open trash bins, and the trick is spreading across Sydney.
Dumpster-diving trash parrots
In a study about these smart birds just published in Science, researchers define animal culture as "population-specific behaviors acquired via social learning from knowledgeable individuals."
Co-lead author of the study Barbara Klump of the Max Planck Institute of Animal Behavior in Konstanz, Germany says, "[C]ompared to humans, there are few known examples of animals learning from each other. Demonstrating that food scavenging behavior is not due to genetics is a challenge."
An opportunity presented itself in a video that co-author Richard Major of the Australian Museum shared with Klump and the other co-authors. In the video, a sulphur-crested cockatoo used its beak to pull up the handle of a closed garbage bin — using its foot as a wedge — and then walked back the lid sufficiently to flip it open, exposing the bin's edible contents.
Major has been studying Cacatua galerita for 20 years and says, "Like many Australian birds, sulphur-crested cockatoos are loud and aggressive." The study describes them as a "large-brained, long-lived, and highly social parrot." Says Major, "They are also incredibly smart, persistent, and have adapted brilliantly to living with humans."(Research regarding some of the ways in which wild animals adapt to the presence of humans has already produced some fascinating results and is ongoing.)
Clever cockie opens bin - 01 youtu.be
The researchers became curious about how widespread this behavior might be and saw a research opportunity. After all, says John Martin, a researcher at Taronga Conservation Society, "Australian garbage bins have a uniform design across the country, and sulphur-crested cockatoos are common across the entire east coast."
Martin continues, "In 2018, we launched an online survey in various areas across Sydney and Australia with questions such as, 'What area are you from, have you seen this behavior before, and if so, when?'"
Word Gets Around
Credit: magspace/Adobe Stock
Although the cockatoos' maneuver was reported in only three suburbs before 2018, by the end of 2019, people in 44 areas reported observing the behavior. Clearly, more and more cockatoos were learning how to successfully dumpster dive.
As further proof, says Klump, "We observed that the birds do not open the garbage bins in the same way, but rather used different opening techniques in different suburbs, suggesting that the behavior is learned by observing others." One individual bird in north Sydney invented its own method, and the scientists saw it grow in popularity throughout the local population.
To track individual birds, the researchers marked 500 cockatoos with small red dots. Subsequent observations revealed that not all cockatoos are bin-openers. Only about 10 percent of them are, and they are mostly males. The other cockatoos apparently restrict their education to a different lesson: hang around with a bin-opener, and you will get supper.
Thanks to the surveys, the researchers consider the entire project to be a valuable citizen-science experiment. "By studying this behavior with the help of local residents, we are uncovering the unique and complex cultures of their neighborhood birds."
The few seconds of nuclear explosion opening shots in Godzilla alone required more than 6.5 times the entire budget of the monster movie they ended up in.