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Gizmorama - May 22, 2017

Good Morning,


Can you guess the inspiration for the future of hearing aids? Well, if you said parasitic fly, then you must have read the subject line of this particular newsletter.

Learn about this and more interesting stories from the scientific community in today's issue.

Until Next Time,
Erin


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*-- Can a parasitic fly inspire a new generation of hearing aids? --*

Ormia ochracea, a small, yellow, nocturnal fly native to Mexico and the southern United States has the most powerful directional hearing in the animal kingdom.

Scientists hope the fly's hearing mechanism can inspire the next generation of auditory sensors, but new research suggests the fly's hearing mechanism has limitations.

"These flies have highly specialized ears that provide the most acute directional hearing of any animal," Andrew Mason, a professor of biology at the University of Toronto, Scarborough, said in a news release. "The mechanism that makes their hearing so exceptional has even led to a range of bio-inspired technology, like the mini directional microphones used in hearing aids."

Unlike most animal ears, the fly's are connected. A pair of eardrums are connected by a bendable joint. When one is stimulated, the vibrations reverberate across to the other. The time delay helps the fly pinpoint the direction of the sound.

The remarkable ability helps the fly locate the songs of male crickets. Ormia ochracea is parasitic. The females burrow their eggs in the cricket. The fly's larvae eat the cricket alive as they develop.

Unfortunately, for auditory engineers, the mechanism that makes the hearing of Ormia ochracea so remarkable isn't easily translated to new technology.

One of the main challenges for engineers designing improved hearing aids is the "cocktail-party-problem." How can a hearing aid be designed to isolated target sound in a noisy environment. For humans, the brain and auditory system work together to hone in on localized sounds -- the ability is called "spatial release from masking," or SRM.

The ears Ormia ochracea can't perform SRM. Lab tests showed the fly is easily pulled away from its target by distracting sounds.

"A distracting noise that is more to one side will cause an auditory illusion by obscuring the signal in that ear," said Mason. "It essentially ends up fooling the fly into perceiving that the signal is coming from one place, so it ends up pushing it away from the actual cricket sound."

The new research, detailed in the journal eLife, highlights a potential limitation of mechanically-coupled hearing devices.

"These flies are very accurate for one thing, which is detecting cricket sounds, but that comes at a cost since they've evolved to focus on this very restrictive set of information," Mason said.



*-- Revolutionary new sunscreen features melanin-mimicking nanoparticles --*

Researchers at the University of California, San Diego have created a sunscreen that both mimics and enhances the skin's natural protective abilities.

A team of chemists, materials scientists and nanoengineers were able to tap into the skin's defense mechanisms using nanoparticles of oxidized dopamine. Tests showed the particles mimic melanosomes, the organelle in skin cells that synthesizes, stores and transports melanin.

Researchers first developed the nanoparticles two years ago while studying the behavior of melanins in bird feathers.

"We hypothesized that synthetic melanin-like nanoparticles would mimic naturally occurring melanosomes and be taken up by keratinocytes, the predominant cell type found in the epidermis, the outer layer of skin," Nathan Gianneschi, a professor of biochemistry, materials science and engineering at UC San Diego, said in a news release.

Researchers believe their breakthrough could yield treatments for vitiligo and albinism, diseases caused by defects in the body's melanin production system. Patients diagnosed with vitiligo and albinism are at a much higher risk of skin cancer.

"The widespread prevalence of these melanin-related diseases and an increasing interest in the performance of various polymeric materials related to melanin prompted us to look for novel synthetic routes for preparing melanin-like materials," Gianneschi said.

Melanosomes are produced by cells called melanocytes, found among the bottom layers of the epidermis. The organelles deliver melanin to keratinocytes, skin cells in the upper layer of the epidermis. There, melanin goes to work protecting skin cells from ultraviolet radiation.

In lab tests using tissue culture, researchers showed the nanoparticles are absorbed and distributed throughout keratinocytes just like natural melanin. The nanoparticles also protected skin cells from DNA damage caused by ultraviolet radiation.

Researchers described their breakthrough in the journal ACS Central Science.

"Considering limitations in the treatment of melanin-defective related diseases and the biocompatibility of these synthetic melanin-like nanoparticles in terms of uptake and degradation, these systems have potential as artificial melanosomes for the development of novel therapies, possibly supplementing the biological functions of natural melanins," the scientists wrote in their paper.

***

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