Nano bulb lights novel path: Engineers create tunable, nanoscale, incandescent light source
What may be viewed as the world’s smallest incandescent lightbulb is shining in a Rice University engineering laboratory with the promise of advances in sensing, photonics and perhaps computing platforms beyond the limitations of silicon.
Gururaj Naik of Rice’s Brown School of Engineering and graduate student Chloe Doiron have assembled unconventional “selective thermal emitters”—collections of near-nanoscale materials that absorb heat and emit light.
Their research, reported in Advanced Materials, one-ups a recent technique developed by the lab that uses carbon nanotubes to channel heat from mid-infrared radiation to improve the efficiency of solar energy systems.
The new strategy combines several known phenomena into a unique configuration that also turns heat into light—but in this case, the system is highly configurable.
Basically, Naik said, the researchers made an incandescent light source by breaking down a one-element system—the glowing filament in a bulb—into two or more subunits. Mixing and matching the subunits could give the system a variety of capabilities.
“The previous paper was all about making solar cells more efficient,” said Naik, an assistant professor of electrical and computer engineering. “This time, the breakthrough is more in the science than the application. Basically, our goal was to build a nanoscale thermal light source with specific properties, like emitting at a certain wavelength, or emitting extremely bright or new thermal light states.
“Previously, people thought of a light source as just one element and tried to get the best out of it,” he said. “But we break the source into many tiny elements. We put sub-elements together in such a fashion that they interact with each other. One element may give brightness; the next element could be tuned to provide wavelength specificity. We share the burden among many small parts.
“The idea is to rely upon collective behavior, not just a single element,” Naik said. “Breaking the filament into many pieces gives us more degrees of freedom to design the functionality.”
The system relies on non-Hermitian physics, a quantum mechanical way to describe “open” systems that dissipate energy—in this case, heat—rather than retain it. In their experiments, Naik and Doiron combined two kinds of near-nanoscale passive oscillators that are electromagnetically coupled when heated to about 700 degrees Celsius. When the metallic oscillator emitted thermal light, it triggered the coupled silicon disk to store the light and release in the desired manner, Naik said.
The light-emitting resonator’s output, Doiron said, can be controlled by damping the lossy resonator or by controlling the level of coupling through a third element between the resonators. “Brightness and the selectivity trade off,” she said. “Semiconductors give you a high selectivity but low brightness, while metals give you very bright emission but low selectivity. Just by coupling these elements, we can get the best of both worlds.”
“The potential scientific impact is that we can do this not just with two elements, but many more,” Naik said. “The physics would not change.”
He noted that though commercial incandescent bulbs have given way to LEDs for their energy efficiency, incandescent lamps are still the only practical means to produce infrared light. “Infrared detection and sensing both rely on these sources,” Naik said. “What we’ve created is a new way to build light sources that are bright, directional and emit light in specific states and wavelengths, including infrared.”
The opportunities for sensing lie at the system’s “exceptional point,” he said.
“There’s an optical phase transition because of how we’ve coupled these two resonators,” Naik said. “Where this happens is called the exceptional point, because it’s exceptionally sensitive to any perturbation around it. That makes these devices suitable for sensors. There are sensors with microscale optics, but nothing has been shown in devices that employ nanophotonics.”
The opportunities may also be great for next-level classical computing. “The International Roadmap for Semiconductor Technology (ITRS) understands that semiconductor technology is reaching saturation and they’re thinking about what next-generation switches will replace silicon transistors,” Naik said. “ITRS has predicted that will be an optical switch, and that it will use the concept of parity-time symmetry, as we do here, because the switch has to be unidirectional. It sends light in the direction we want, and none comes back, like a diode for light instead of electricity.”
Instant messaging in proteins discovered
Proteins are essential for every living cell and responsible for many fundamental processes. In particular, they are required as bio-catalysts in metabolism and for signaling inside the cell and between cells. Many diseases come about as a result of failures in this communication, and the origins of signaling in proteins have been a source of great scientific debate. Now, for the first time, a team of researchers at the University of Göttingen has actually observed the mobile protons that do this job in each and every living cell, thus providing new insights into the mechanisms. The results were published in Nature.
Researchers from the University of Göttingen led by Professors Kai Tittmann and Ricardo Mata found a way to grow high-quality protein crystals of a human protein. The DESY particle accelerator in Hamburg made it possible to observe protons (subatomic particles with a positive charge) moving around within the protein. This surprising “dance of the protons” showed how distant sections of the protein were able to communicate instantaneously with each other—like electricity moving down a wire.
In addition, Tittmann’s group obtained high-resolution data for several other proteins, showing in unprecedented detail the structure of a kind of hydrogen bond where two heavier atoms effectively share a proton (known as “low-barrier hydrogen bonding”). This was the second surprise: the data proved that low-barrier hydrogen bonding indeed exists in proteins resolving a decades-long controversy, and in fact plays an essential role in the process.
“The proton movements we observed closely resemble the toy known as a Newton’s cradle, in which the energy is instantly transported along a chain of suspended metal balls. In proteins, these mobile protons can immediately connect other parts of the protein,” explained Tittmann, who is also a Max Planck Fellow at the Max Planck Institute for Biophysical Chemistry in Göttingen. The process was simulated with the help of quantum chemical calculations in Professor Mata’s laboratory. These calculations provided a new model for the communication mechanism of the protons. “We have known for quite some time that protons can move in a concerted fashion, like in water for example. Now it seems that proteins have evolved in such a way that they can actually use these protons for signaling.”
The researchers believe this breakthrough can lead to a better understanding of the chemistry of life, improve the understanding of disease mechanisms and lead to new medications. This advance should enable the development of switchable proteins that can be adapted to a multitude of potential applications in medicine, biotechnology and environmentally friendly chemistry.
Apple Music is now available on Alexa devices in Canada By Dean Daley@deancwdaleySEP 18, 201911:39 AM EDT0 COMMENTS
Apple Music is now available on Alexa devices in Canada. Those with an Apple Music subscription can now listen to music from the platform on their Echo devices with Alexa. Additionally, customers with Alexa built-in devices, like the Sonos One and Sonos Beam, are also able to stream Apple Music via Alexa. First you to enable the Apple Music Skill and link it to your ccount, with either the Skills Store in the Alexa app or on Amazon.ca. With this functionality, you can start listening to Apple Music’s 50 million songs and ask Alexa to play your favourite songs, artists or albums. You can even ask the voice assistant to stream from Apple Music’s radio stations or play music from playlists made by Apple Music’s editors from around the world.
IBM continues to push its quantum computing efforts forward and today announced that it will soon make a 53-qubit quantum computer available to clients of its IBM Q Network. The new system, which is scheduled to go online in the middle of next month, will be the largest universal quantum computer available for external use yet.
The new machine will be part of IBM’s new Quantum Computation Center in New York State, which the company also announced today. The new center, which is essentially a data center for IBM’s quantum machines, will also feature five 20-qubit machines, but that number will grow to 14 within the next month. IBM promises a 95% service availability for its quantum machines.
IBM notes that the new 53-qubit system introduces a number of new techniques that enable the company to launch larger, more reliable systems for cloud deployments. It features more compact custom electronics for improving scaling and lower error rates, as well as a new processor design.
“Our global momentum has been extraordinary since we put the very first quantum computer on the cloud in 2016, with the goal of moving quantum computing beyond isolated lab experiments that only a handful organizations could do, into the hands of tens of thousands of users,” said Dario Gil, the director of IBM Research. “The single goal of this passionate community is to achieve what we call Quantum Advantage, producing powerful quantum systems that can ultimately solve real problems facing our clients that are not viable using today’s classical methods alone, and by making even more IBM Quantum systems available we believe that goal is achievable.”
The fact that IBM is now opening this Quantum Computation itself, of course, is a pretty good indication about how serious the company is about its quantum efforts. The company’s quantum program also now supports 80 partnerships with commercial clients, academic institutions and research laboratories. Some of these have started to use the available machines to work on real-world problems, though the current state of the art in quantum computing is still not quite ready for solving anything but toy problems and testing basic algorithms.
After decades of research, here it is: the first promising evidence in humans, albeit imperfect and early, that a cocktail of three drugs is enough to reverse the epigenetic clock—a measure of someone’s biological age and health.
The results came as a surprise to even the research team, who originally designed the trial for something a little less dazzling: to look at human growth hormone’s effects on the thymus, the cradle of the body’s immune system that deteriorates with age.
“Maintained immune function is seen in centenarians,” and thymus function is linked to all-cause mortality, explained study author Dr. Gregory Fahy at Intervene Immune, based in Los Angeles, California. “So we were hoping to use a year of growth hormone to maintain thymus function in middle-aged men, right before the tissue’s functions take a nosedive,” he said.
Yet something gnawed at the back of his mind. To combat the side effects of growth hormone, which includes dangerously increasing blood sugar levels, the team added in two diabetes drugs as a countermeasure. One is DHEA, a hormone secreted by the adrenal gland. The other, metformin, might spark immediate recognition: based on pre-clinical research it’s one of the most promising anti-aging drugs in the longevity pipeline. All three drugs have been linked to slowing the aging process in the lab.
What if the three-drug combination didn’t just work on the immune system? What if they can actually induce measurable anti-aging effects in humans?
Before terminating the study, Fahy decided to call up Dr. Steve Horvath at the University of California, Los Angeles. The “watcher” of epigenetic clocks, Horvath has spent his career finding measures to assess a person’s biological age, which differs from the number of candles you put on your birthday cake every year but better reflects your “true” age. Taking the drug cocktail for one year shed the participant’s chronological age by 2.5 years on average, while showing signs of immune rejuvenation.
While not a massive change, the results caught the team off guard. “I’d expected to see slowing down of the clock, but not a reversal,” said Horvath. “That felt kind of futuristic.”
It’s not to say we’ve “cured” aging—far from it. But after decades of research in flies, worms, and rodents, this trial in humans, however small and imperfect in control measures, offers hope.
The Hallmarks of Aging
Measuring a person’s “true” age is surprisingly difficult. Due to genetics and lifestyle interventions, a population of 60-year-olds, for example, exhibit a spread in their health and mental status. Compared to chronological age, biological age better correlates with general health status, mental abilities, risk of getting age-related diseases, and death. Yet because aging gradually deteriorates the entire body, scientists have struggled to find the best markers.
In 2013, several research groups pooled their ideas to piece together the hallmarks of aging. Here’s a taste of some ideas: Genomic instability. The shrinking of telomeres, the “protective” endcaps that protect chromosomes, which house our genes. Protein metabolism gone wild. Mitochondria, the energy producers in cells, break down. Depleted stem cells. Zombie cells run rampant.
A combination of markers may form the best “clock” that measures true age. But when it comes to any single measure, one stood out: epigenetic alterations.
Stay with me. The epigenome controls how genes get turned into proteins, and subsequently, tissues, organs, and the whole body. They’re comprised of chemical marks that tag onto the genetic sequence itself, like light switches on every gene lamp. Different marks control whether a gene is turned on or off—methyl groups, for example, shut it off—and the pattern of these tags drastically changes as you age.
For the past few years, Horvath and others screened hundreds of positions on DNA from sample cells to see how often those places have a methyl group. By feeding these epigenetic data into algorithms, the teams have uncovered several mathematical clocks that can remarkably estimate a cell’s—and a person’s—true biological age.
“The greatest hope is that this clock measures the output of a process that really does relate to aging—even causes aging,” said Horvath.
An Immune Restoration
The new study’s initial focus wasn’t epigenetic clocks; rather, it was the immune system. The thymus, a tiny gland nestled between the lungs and the breastbone, helps nurture immune white cells to their full function to combat infections and cancers. The thymus is critical for maintaining the immune system, but it’s fragile. It begins to shrink after puberty and fills with fatty deposits, which correlates to all sorts of immune troubles.
Nearly 16 years ago, when Fahy was 46 years old, he reviewed promising studies using growth hormones to restore thymus functions in animals and grew convinced that he found the solution to restoring the organ’s function. With striking commitment, he jabbed himself with growth hormones and the diabetes drug DHEA for a month, and found signs of regeneration in his own thymus.
The new TRIM (Thymus Regeneration, Immunorestoration and Insulin Mitigation) trial built on Fahy’s self-experimentation. The study recruited nine white men aged between 51 and 65 years old, and dosed them with the three-drug combo for a year: growth hormone for restoration, and DHEA and metformin to combat high blood sugar. The latter two were also partly chosen for their promising anti-aging effects in animals.
During the trial, the team regularly took blood samples to analyze immune cell counts, and used medical imaging to check the composition of their thymus. With age, the number of different immune cell type changes, with potentially detrimental effects. At the end of the trial, not only were the cell changes reversed, the participants’ thymus also showed less signs of fat—they’d been replaced by healthy, regenerated tissue.
A Surprising Rewind
Studying epigenetic clocks came as an afterthought. After the trial was completed, Fahy reached out to Horvath to take a second look at the data.
The results came as a surprise to both. Using four different epigenetic clocks, Horvath measured the biological age of each participant. Every single time he found that the clock rewound: the participants’ epigenetic age was, on average, 1.5 years slower than when they first entered the trial. Rather than aging, they had a Benjamin Button moment. What’s more, at nine months of treatment, the de-aging effect seemed to accelerate—that is, the longer they took the drug, the faster their epigenetic clocks seemed to rewind. The effects lasted for at least six months after they stopped taking the drugs.
Because the results were so consistent and lasting, Horvath is optimistic it’s not a fluke, even with a small sample size. De-aging effects aside, other measures also proved promising: one of the most dangerous side effects of rejuvenation is cancer, characterized by “immortal” cells. Although the study only looked at prostate cancer, a high-risk potential, they didn’t find any biomarkers hinting at a dangerous turn.
The study is hardly the final word on rejuvenation in humans. Because the study is so small and “not very well controlled,” said Dr. Wolfgang Wagner at the University of Aachen in Germany, who was not involved in the study, “the results are not rock solid.”
More importantly, the authors don’t know how the drugs are working. Their main idea is that they’re acting on the same molecular pathways as restricting calories, which is also a strong de-aging intervention in animals. In addition, epigenetic age isn’t synonymous with biological age, though it’s a tight approximation in terms of age-related health risks.
Regardless, the results are promising. Intervene Immune is now planning a larger trial with a more diverse population, including different age and ethnic groups and women, to further gauge efficacy.
As the authors concluded: “This is to our knowledge the first report of an increase, based on an epigenetic age estimator, in predicted human lifespan by means of a currently accessible aging intervention.” It won’t be the last.