Is magnesium the sleeping potion that enables sandhoppers to survive cold winters?

Magnesium compounds are a common ingredient of many remedies designed to help people wind down and escape the stresses of modern life.

However, a new study has shown it is not only humans that are using forms of the chemical as a way to help them survive challenging conditions.

In tests conducted on beaches in Cornwall, and in the laboratory at the University of Plymouth, scientists confirmed the findings of previous studies which showed large sandhoppers (Talitrus saltator) increase the levels of magnesium ions in their bodies as temperatures fall. This slows them down so they are less active than they would be during the warmer months.

However, the new study has shown for the first time that when they want to enter a period of deep sleep the creatures have the means through which to increase their magnesium levels even further — in some instances more than doubling them.

Essentially acting as a natural narcotic, the magnesium puts the sandhopper into a torpid state. This enforced rest means that the creatures stay hidden in burrows up to 30cm beneath the beach surface, without the need to come up for food or water, and to some extent buffered from the wintery conditions at the surface of the sand.

The study — which focused on the sandhopper population at Portwrinkle, in South East Cornwall — was carried out by Professor of Marine Zoology John Spicer and BSc (Hons) Marine Biology graduate Jack Bush.

Writing in the Journal of Experimental Marine Biology and Ecology, they say it sheds further light on why large sandhoppers seem to disappear from sandy beaches during cold winter weather.

Professor Spicer has spent decades studying the impact of temperature on marine and coastal species, including a number of studies on sandhoppers in Scotland.

He said: “It has been known for over a century that large sandhoppers, relatives of shrimp and crabs, can overwinter buried deep in the sand at the top of beaches away from the reach of the tide. What our study shows is that they may help themselves ‘go to sleep’ by allowing a natural narcotising agent, magnesium ions, to build up in their body fluids.

“Fluids containing magnesium, like Epsom salts, are routinely used by humans to relax but also when aquatic animals are being examined as part of scientific investigations. Our study shows nature has also found a way to do that without outside involvement.

“That said, as it’s a temperature dependent process it does raise questions over what will happen as our world warms. Will sandhoppers no longer sleep and just eat decomposing wrack all day long? Or will they change their sleeping habits by adapting the way they manage the magnesium in their body fluids?”

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New metric for blood circulation in brain to better understand dementia

Each time the heart beats, it pumps blood through the brain vessels, causing them to expand slightly and then relax, much like the rise and fall of the blood pulsing through your veins when you feel your pulse in your wrist. This pulsation in the brain helps distribute blood evenly across different areas of the brain, ensuring that all parts receive the oxygen and nutrients they need to function properly. In healthy vessels, the pulse wave is dampened before it reaches the smallest vessels, where high pulsatility could be harmful. This new metric provides a comprehensive measure of the small vessel pulsatility risk.

A paper just published in Scientific Reports- Nature by Sergio Dempsey as first author with colleagues Dr Soroush Safaei, Dr Gonzalo Maso Talou at Auckland Bioengineering Institute, along with co-author Dr Holdsworth (Mātai and FMHS & CBR at the University of Auckland), describes the new metric based on 4D flow MRI technology.

This innovative metric is particularly crucial because increased vascular pulsatility is linked to several brain conditions, including Alzheimer’s disease and other forms of dementia. By accurately measuring how pulsatility is transmitted in the brain, researchers can better understand the underlying mechanism of these diseases and potentiall guide development f new treatments.

Current MRI methods face limitations due to anatomical variations and measurement constraints. The new technique removes this issue by integrating thousands of measurements across all brain vessels, rather than looking one spot at a time as the traditional methods. This provides a richer metric representative of the entire brain.

“The ability to measure how pulsatility is transmitted through the brain’s arteries could revolutionise our approach to neurological diseases, and support research in vascular damage hypotheses” explained Mr. Dempsey. “Our method allows for a detailed assessment of the brain’s vascular health, which is often compromised in neurodegenerative disorders.”

The study also highlighted the potential to enhance clinical assessments and research on brain health. By integrating this new metric into routine diagnostic procedures, healthcare providers can offer more precise and personalised care plans for individuals at risk of or suffering from cognitive impairments.

In addition to its implications for patient care, the researchers have made their tools publicly available, integrating them into pre-existing open-source software. This enables scientists and clinicians worldwide to adopt the advanced methodology, fostering further research and collaboration in the field of neurology.

The research team is planning further studies to explore the applications of this technique in larger and more diverse populations, beginning with the “Digital Twin Dementia Study” starting at Mātai later this month. Results from the initial study of the metric also identified important sex differences in vascular dynamics which has initiated a new study focussing on sex-related dynamics which is anticipated to begin at Mātai and the Centre for Advanced MRI (CAMRI) in November.

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New approach to identifying altermagnetic materials

Magnetic materials have traditionally been classified as either ferromagnetic, like the decorative magnets on iron refrigerator doors that are seemingly always magnetic, or antiferromagnetic, like two bar magnets placed end-to-end with opposite poles facing each other, canceling each other out so that the material has no net magnetism. However, there appears to be a third class of magnetic materials exhibiting what in 2022 was dubbed altermagnetism.

Microscopically, magnetism arises from a collection of tiny magnets associated with electrons, called spin. In ferromagnetic materials, all the electron spins point in the same direction, while in antiferromagnetic materials, the electron spins are aligned in opposite directions, half pointing one way and half the other, canceling out the net magnetism. Altermagnetic materials are proposed in theory to possess properties combining those of both antiferromagnetic and ferromagnetic materials. One potential application of altermagnetic materials is in spintronics technology, which aims to utilize the spin of electrons effectively in electronic devices such as next-generation magnetic memories. However, identifying altermagnets has been a challenge.

An international research group led by Associate Professor Atsushi Hariki from the Graduate School of Engineering at Osaka Metropolitan University pioneered a new method to identify altermagnets, using manganese telluride (α-MnTe) as a testbed.

With the aid of a supercomputer, the researchers theoretically predicted a fingerprint of altermagnetism in X-ray magnetic circular dichroism (XMCD), which measures the absorption difference between left- and right-circularly polarized light. Then, using the Diamond Light Source synchrotron in England, they experimentally demonstrated the XMCD spectrum for altermagnetic α-MnTe for the first time in the world.

“Our results show that XMCD is an effective method for the simple identification of altermagnetic materials,” Professor Hariki said. “Also, it can be expected to further accelerate the application of altermagnets in spintronics.”

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A liquid crystal source of photon pairs

Spontaneous parametric down-conversion (SPDC), as a source of entangled photons, is of great interest for quantum physics and quantum technology, but so far it could be only implemented in solids. Researchers at the Max Planck Institute for the Science of Light (MPL) and Jozef Stefan Institute in Ljubljana, Slovenia, have demonstrated, for the first time, SPDC in a liquid crystal. The results, recently published in Nature, open a path to a new generation of quantum sources: efficient and electric-field tunable.

The splitting of a single photon in two is one of the most useful tools in quantum photonics. It can create entangled photon pairs, single photons, squeezed light, and even more complicated states of light which are essential for optical quantum technologies. This process is known as spontaneous parametric down-conversion (SPDC).

SPDC is deeply linked to central symmetry. This is the symmetry with respect to a point — for instance, a square is centrally symmetric but a triangle is not. In its very essence — a splitting of one photon in two — SPDC breaks the central symmetry. Therefore, it is only possible in crystals whose elementary cell is centrally asymmetric. SPDC cannot happen in ordinary liquids or gases, because these materials are isotropic.

Recently, however, researchers have discovered liquid crystals that have a different structure, the so-called ferroelectric nematic liquid crystals. Despite being fluidic, these materials feature strong central symmetry breaking. Their molecules are elongated, asymmetric and, most importantly, they can be re-oriented by external electric field. Re-orientation of molecules changes the polarization of the generated photon pairs, as well as the generation rate. Given a proper packaging, a sample of such material can be a very useful device because it produces photon pairs efficiently, can be easily tuned with electric field, and can be integrated into more complex devices.

Using the samples prepared in Jozef Stefan Institute (Ljubljana, Slovenia) from a ferroelectric nematic liquid crystal synthesized by Merck Electronics KGaA, researchers at the Max-Planck Institute for the Science of Light have implemented SPDC, for the first time, in a liquid crystal. The efficiency of entangled photons generation is as high as in the best nonlinear crystals, such as lithium niobate, of similar thickness. By applying an electric field of just a few Volts, they were able to switch the generation of photon pairs on and off, as well as to change the polarization properties of these pairs. This discovery starts a new generation of quantum light sources: flexible, tunable, and efficient.

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A new weapon in the battle against antibiotic resistance: Temperature

Scientists from the University of Groningen (the Netherlands), together with colleagues from the University of Montpellier (France) and the University of Oldenburg (Germany), have tested how a fever could affect the development of antimicrobial resistance. In laboratory experiments, they found that a small increase in temperature from 37 to 40 degrees Celsius drastically changed the mutation frequency in E. coli bacteria, which facilitates the development of resistance. If these results can be replicated in human patients, fever control could be a new way to mitigate the emergence of antibiotic resistance. The results were published in the journal JAC-Antimicrobial Resistance.

Antimicrobial resistance of pathogens is a worldwide problem, and recognized by the WHO as one of the top global public health and development threats. There are two ways to fight this: by developing new drugs, or by preventing the development of resistance. ‘We know that temperature affects the mutation rate in bacteria’, explains Timo van Eldijk, co-first author of the paper. ‘What we wanted to find out was how the increase in temperature associated with fever influences the mutation rate towards antibiotic resistance.’

Three antibiotics

‘Most studies on resistance mutations were done by lowering the ambient temperature, and none, as far as we know, used a moderate increase above normal body temperature,’ Van Eldijk reports. Together with Master’s student Eleanor Sheridan, Van Eldijk cultured E. coli bacteria at 37 or 40 degrees Celsius, and subsequently exposed them to three different antibiotics to assess the effect. ‘Again, some previous human trials have looked at temperature and antibiotics, but in these studies the type of drug was not controlled.’ In their laboratory study, the team used three different antibiotics with different modes of action: ciprofloxacin, rifampicin, and ampicillin.

The results showed that for two of the drugs, ciprofloxacin and rifampicin, increased temperature led to an increase in the mutation rate towards resistance. However, the third drug, ampicillin, caused a decrease in the mutation rate towards resistance at fever temperatures. ‘To be certain of this result, we actually replicated the study with ampicillin in two different labs, at the University of Groningen and the University of Montpellier, and got the same result,’ says Van Eldijk.

Fever-suppressing drugs

The researchers hypothesized that a temperature dependence of the efficacy of ampicillin could explain this result, and confirmed this in an experiment. This explains why ampicillin resistance is less likely to arise at 40 degrees Celsius. ‘Our study shows that a very mild change in temperature can drastically change the mutation rate towards resistance to antimicrobials,’ concludes Van Eldijk. ‘This is interesting, as other parameters such as the growth rate do not seem to change.’

If the results are replicated in humans, this could open the way to tackling antimicrobial resistance by lowering the temperature with fever-suppressing drugs, or by giving patients with a fever antimicrobial drugs with higher efficacy at higher temperatures. The team concludes in the paper: ‘An optimized combination of antibiotics and fever suppression strategies may be a new weapon in the battle against antibiotic resistance.’

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What we know about Kate’s cancer treatment

The Princess of Wales continues on preventative chemotherapy with “good and bad days”.

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Top doctor alarmed by weight-loss drug misuse

The drugs should not be used as “a quick fix” to get “beach-body ready” this summer, NHS England’s medical director said.

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Balding at 16 and unable to look in the mirror

Poppie Davies wore a wig and talked about how isolated she felt with the condition.

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Silent Men film asks why so many still struggle to open up

Scottish filmmaker Duncan Cowles set out to ask why men tend to bottle up their emotions.

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New fabric makes urban heat islands more bearable

This year has already seen massive heatwaves around the globe, with cities in Mexico, India, Pakistan and Oman hitting temperatures near or past 50 degrees Celsius (122 degrees Fahrenheit).

As global temperatures and urban populations rise, the world’s cities have become “urban heat islands,” with tight-packed conditions and thermal radiation emitting from pavement and skyscraper trapping and magnifying these temperatures. With 68 percent of all people predicted to live in cities by 2050, this is a growing, deadly problem.

In a paper published today in Science, researchers from the UChicago Pritzker School of Molecular Engineering (PME) detail a new wearable fabric that can help urban residents survive the worst impacts of massive heat caused by global climate change, with applications in clothing, building and car design, and food storage.

In tests under the Arizona sun, the material kept 2.3 degrees Celsius (4.1 degrees Fahrenheit) cooler than the broadband emitter fabric used for outdoor endurance sports and 8.9 degrees Celsius (16 degrees Fahrenheit) cooler than the commercialized silk commonly used for shirts, dresses and other summer clothing.

This, the team hopes, will help many avoid the heat-related hospitalizations and deaths seen in global population centers this year alone.

“We need to reduce carbon emission and make our cities carbon negative or carbon neutral,” PME Asst. Prof. Po-Chun Hsu said. “But meanwhile, people are feeling the impact of these high temperatures.”

‘You have to consider the environment’

Existing cooling fabric for outdoor sports works by reflecting the sun’s light in a diffuse pattern so it doesn’t blind onlookers. But in an urban heat island, the sun is only one source of heat. While the sun bakes from above, thermal radiation emitted from buildings and pavement blast city-dwellers with blistering heat from the sides and below.

This means many materials that perform well in lab tests won’t help city-dwellers in Arizona, Nevada, California, Southeast Asia and China when predicted massive heatwaves hit them over the next few weeks.

“People normally focus on the performance or the material design of cooling textiles,” said co-first author Ronghui Wu, a postdoctoral researcher at PME. “To make a textile that has the potential to apply to real life, you have to consider the environment.”

One simple example of considering the environment is that people stand. They are wearing materials designed to reflect direct sunlight, but only their hats, shoulder coverings and the tops of their shoes — about 3 percent of their clothing — face that direct light. The other 97 of their clothes are being heated by the thermal radiation coming at them from the sides and below, which broadband emitter fabric does not fight.

The sun and sidewalk cook with different heats. Creating one material capable of protecting wearers from both provided a major engineering challenge for the team.

“Solar is visible light, thermal radiation is infrared, so they have different wavelengths. That means you need to have a material that has two optical properties at the same time. That’s very challenging to do,” said co-first author Chenxi Sui, a PhD candidate at PME. “You need to play with material science to engineer and tune the material to give you different resonances at different wavelengths.”

The costs of comfort

Cooling a home too often means warming the planet, with the carbon impact of air conditioning and refrigeration systems contributing to climate change.

“Our civilization actually uses about 10 to 15 percent of the energy in total just to make ourselves feel comfortable wherever we go,” Hsu said.

The risk from heat is not distributed evenly, however. In the U.S. and Japan, more than 90 percent of households have an air conditioner, a number that drops to 5 percent in India and parts of Africa.

The PME team’s new textile, which has received a provisional patent, can help provide a passive cooling system that can supplement and reduce the need for energy- and cost-intensive systems.

The applications go far beyond clothing.

A thicker version of the fabric protected by an invisible layer of polyethylene could be used on the sides of buildings or cars, lowering internal temperatures and reducing the cost and carbon impact of air conditioning. Similarly, the material could be used to transport and store milk and other foods that would otherwise spoil in the heat, cutting refrigeration’s impact.

“You can save a lot of cooling, electricity and energy costs because this is a passive process,” Sui said.

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