You may have missed… bees’ “waggle dance”, artificial muscles, deep-sea mining noise & new Alzheimer’s research.

New material for flexible artificial muscles

Scientists have developed a new material and manufacturing process to create artificial muscles that are stronger and more flexible than their biological counterparts.

Dielectric elastomers (DEs) are natural or synthetic substances that can change in size or shape when stimulated by an electric field. They’re usually made out of acrylic or silicone, but for a soft material to be used as an artificial muscle it mustn’t easily lose its form and strength after repeated use.

Silicones can’t withstand high strain, and traditional acrylic DEs require pre-stretching, and lack flexibility. So, the research team created an improved acrylic-based material using commercially available chemicals and an ultraviolet (UV) light-curing process.

The high-performance dielectric elastomer film (PHDE) is only about 35 micrometres thick, and when multiple layers are stacked together they become a miniature electric motor that can act like muscle tissue and produce enough energy to power motion for small robots or sensors.

The research has been published in Science.

Video showing PHDE films and actuators undergoing tests. These could be used in artificial muscles. Credit: Soft Materials Research LabUCLA

Cryopreserving native Australian macadamia nuts

Most people who shop for macadamias might not know that they’re actually at serious risk of extinction in the wild. While there are plenty of macadamia trees in agriculture around the world, the four wild species – which are endemic to eastern Australian rainforests – are all listed as threatened.

About 60–80% of macadamia habitat has been lost due to land clearing, putting at risk many other native plant and animal species that share those habitats.

But researchers from the Australian Institute of Botanical Science and the University of Queensland are figuring out new ways to store wild and cultivated macadamia genetic material to ultimately ensure the long-term survival of the species.

Macadamia seeds being germinated.
Macadamia seeds being germinated. Credit: Australian Institute of Botanical Science/University of Queensland

They’ve discovered that macadamia seeds are hard to preserve by seed banking.

“These seeds have a very high content of lipids (oils) which can produce problematic crystals when you’re trying to freeze them,” explains Dr Karen Sommerville, a conservation scientist at the institute. “The seeds are also quite big, so it’s possible they’re just not freezing or thawing fast enough to avoid damage from those crystallised lipids.”

Instead, they’ll be attempting to preserve just the tiny embryo in the macadamia kernel (at a much colder -196°C) and develop techniques for growing macadamia plants in tissue culture and cryopreserving the tiny shoot tips.

A driving force of Alzheimer’s disease

Alzheimer’s disease, the most common form of dementia, currently has no cure or effective therapy. This is in part due to gaps in scientists’ understanding of how it arises in the brain.

Now, a new study has shown how the protein called tau, a critical factor in the development of Alzheimer’s disease, turns from normal to a disease state. The research has been published in Science Advances.

Tau accumulates in deposits inside brain cells. During this process it gets heavily modified – there are multiple small changes at many different positions within the tau protein – but until now it’s been unclear exactly how tau becomes progressively modified.

The Flinders University researchers set out to determine whether one change at one specific spot in tau would make it easier for another spot to be modified, and were able to identify “master sites” in tau – specific spots that regulate subsequent modifications at most of the other sites.

They also found that mice did not develop memory deficits when they had a version of tau that lacked one of the identified master sites, compared with mice that had the usual version of tau.

The team will now investigate how these findings can be translated into a potential treatment.

Deep sea mining noise schematics
Sources of noise from deep-sea mining activities will span the entire water column, from rigs at the surface, mining tools at the seabed, and pumps along risers to bring nodules to the surface. Credit: Williams, et al. (2022)

Deep-sea mining noise pollution

The deep sea is home to organisms found nowhere else on Earth, many of whom likely use sound to navigate, communicate, find mating partners, locate food, and detect predators and other dangers.

Seventeen contractors are currently exploring the possibility of mining in the Clarion-Clipperton Zone (CCZ), an area spanning 4.5 million square kilometres between Hawaii and Mexico. But underwater noise pollution from deep-sea mining operations could affect the understudied species that live there.

A new study involving Australian scientists has used computer modelling to find that noise from one mine alone could travel approximately 500km in gentle weather conditions, with cumulative impacts likely in places where multiple mines operate.

The researchers had to use noise levels from better-studied industrial activities – such as oil and gas industry ships and coastal dredges – as placeholders in their modelling because, although mining companies are already testing smaller-scale prototypes of deep-sea mining systems, they have yet to share their data on underwater noise pollution.

The research has been published in Science.

Bees’ “waggle dance” could revolutionise how robots communicate

Honeybees take non-verbal communication to a whole new level by wiggling their backsides to let others know where nearby food is. It’s called the “waggle dance” and the movements communicate the direction of food (with respect to the hive and the sun), and the dance’s duration lets other bees know how far away the food is.

Now, mechanical engineers have taken inspiration from this dance to devise a new way for robots to communicate with humans and each other, according to a new study in Frontiers in Robotics and AI.

They designed a visual communication system with on-board cameras and algorithms that allow the robots to interpret what they see, testing it in a scenario where a package in a warehouse needs to be moved.

A human could communicate where the package is to go with a “messenger” robot using gestures (like a raised hand with a closed fist), and this information could then be conveyed on to a “handling” robot that performs the task.

This was done by tracing a shape on the floor, with the shape’s orientation and the time taken to trace it telling the handling robot the direction and distance of travel.

Putting it to test in a computer simulation and with real robots and humans, the robots interpreted the gestures correctly 90% and 93.3% of the time, respectively.

“This technique could be useful in places where communication network coverage is insufficient and intermittent, such as robot search-and-rescue operations in disaster zones or in robots that undertake space walks,” concludes senior author Abhra Roy Chowdhury, assistant professor of robotics and automation at the Indian Institute of Science.

Robots cooperate with humans and other robots to deliver packages, recognizing human gestures and communicating with honeybee-inspired dances. Credit: K Joshi & AR Chowdhury

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