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Scientists make metals as light as air

Metal as light as air? A group of researchers at the Lawrence Livermore National Laboratory are trying. The researchers are trying to make heavy metals like gold, silver and copper “as light as air, in a form so small that it can be carried on the back of a mosquito.”

The researchers created a kind of ultra-low-density metal “foam.” It is an aerogel made up of many randomly connected nanometric-sized wires that form a sort of miniature “marshmallow.” This structure contains, in proportion, the same number, or even less, of air atoms.

The creation of ultra-low density metal structures is a ten-year field of research but, as reported by the physicist Sergei Kucheyev, engaged in this last study, only in the last two years have foams been obtained “of this incredible quality.” These materials with very low density will prove useful for experiments conducted with laser sources of X-rays useful in turn to further probe the properties of various materials in the most extreme conditions.

However, these new materials could also be applied to other uses, such as protective cushions or coatings. The team has now succeeded in making copper and silver foams and is concentrating on the production of gold and tin foams.

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Strange fish from the depths with transparent teeth studied by scientists

A group of researchers from the University of California in San Diego analyzed the teeth of sea dragons (Aristostomias scintillans) characterized by a remarkable degree of transparency. This unique adaptation allows these fish to prey more successfully. Scientists have discovered an unusual crystalline nanostructure at the base of their teeth, a discovery that could be of inspiration for the construction of transparent or semi-transparent materials with a similar structure.

The research, published in Matter, describes the transparent teeth of sea dragons (dragonfish), an adaptation that, unlike others related to marine animals, such as bioluminescence, has never been properly analyzed on a scientific level, as pointed out by Audrey Velasco-Hogan, the first author of the study that adds: “By studying why these teeth are transparent, we can better understand deep-water organisms such as dragonfish and the adaptations that have evolved to live in their environments.”

Thanks to their transparent teeth, combined with the fact that their bodies are almost completely dark, these fish are essentially invisible to their prey. This makes them excellent predators despite the habitat in which they live, the depths of the sea, is not very generous in terms of the presence of light and despite the fact that they are fish considered as slow. Basically, these fishes spend most of their time waiting for the prey that approach. The same prey cannot notice the protruding teeth that do not reflect light being transparent and therefore meet their destiny.

The teeth of these fish have unique characteristics with regard to both the outer enamel and the inner layer of dentin. The outer layer is made of hydroxyapatite nanocrystals, a structure that prevents light reflection. But also the inner layer is quite particular: there are no classic microscopic channels, called dentine tubules, which are the basis of the teeth of many animals. The absence of these tubules means that the teeth are transparent.

These discoveries could be useful for creating a transparent material in the laboratory.

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Voice recognition algorithm “translates” children’s crying

A group of researchers claim to have created a software tool based on artificial intelligence that is capable of distinguishing the cries of children. Very often parents find themselves unable to understand the real need for a crying child because they are not able to distinguish what can be considered as minimal nuances and changes in tone in the voice that, as several previous studies have shown, may indicate different needs.

The method is based on a modified language recognition algorithm so that it can work on crying. In addition to being useful in the home, it could also be useful in the health sector: for example, it could help doctors to understand the crying of children in the hospital or in serious conditions.

The study, published in the IEEE/CAA Journal of Automatica Sinica, explains how the algorithm is able to identify the patterns hidden in the cries of children, although the crying of each child can be considered as unique. There are in fact some basic characteristics that are common and that are dictated by the same needs or reasons.

The algorithm is independent, however, from the individual infant: it can be used universally since it can recognize and classify the various characteristics of crying and can also understand the level of urgency related to the need that the child intends to communicate.

“We are studying collaborations with hospitals and medical research centres, to obtain more data and input of scenarios and requirements, and we hope to have some products for clinical practice,” say the researchers in relation to the possibility of a practical use of this algorithm.

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New method for purifying water from PFAS substances developed by Australian researchers

A new method for cleaning water from PFAS (polyfluorinated alkyl substances) has been developed by a research group at the University of Flinders, Australia. These substances are usually used in protective coatings, lubricants and other foam-based substances, such as fire protection, and can be extremely toxic because they can end up in drinking water and food. This method, according to the researchers, is low-cost, safe and environmentally friendly.

In Australia in particular, pollution by PFAS substances is very much felt as these are present in fire-fighting foams used almost everywhere, from airports to defence sites. In recent years, various contaminations of groundwater and surface waters have been found near the sites where these foams are used. Researchers at Flinders University have created a new type of absorbent polymer obtained from the growing oil and sulphur combined with powdered activated carbon (PAC).

This new polymer can adhere to the carbon and prevent its agglomeration during water filtration. It works, according to Australian researchers, better than traditional methods, which are based on granular activated carbon, because, in addition to being less expensive, it drastically reduces the amount of dust generated with fewer discs of workers who have to perform the filtration.

“The next step for us is to test this absorbent on a commercial scale and demonstrate its ability to purify thousands of liters of water, we are also studying methods to recycle the sorbent and destroy the PFAS,” says Justin Chalker, one of the authors of the research.

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Elephants know how to quantify food by smell with precision

A particular feature of elephants has been discovered by a group of researchers who published their study on Proceedings of the National Academy of Sciences. Although well analyzed and studied, elephants have a characteristic related to their sense of smell that until now had remained unknown: they are able to quantify the portions of food not only by sight but also by smell.

During various experiments, scientists have in fact discovered that elephants were able to quantify the number of sunflower seeds closed inside several buckets covered with the lid. The elephants clearly showed that they preferred buckets with the largest number of seeds, even though they could not see inside nor can they move the bucket itself. The greater the number of seeds inside the bucket, the greater the number of elephants who preferred the fuller buckets.

This is the first example of an animal that can quantify, in a fairly precise way, the quantity of a material only through the smell.

What can this discovery be used for? Currently, in many regions of the world elephants are considered as annoying for various human activities and the same humans face many difficulties to move them away from different sites of interest. With this discovery, elephants can be directed to a point where food is accumulated more efficiently.

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Nordic microalgae cleans wastewater and produces biodiesel

A further study, written by the researcher of the University of UmeƄ Lorenza Ferro, highlights the importance of microalgae in the environment and the considerable possibilities that these plants offer in the field of biofuel production.

Biomass made of algae has been increasingly taken into account and used in recent years for the production of biofuels because these microorganisms can form and store large amounts of lipids. The latter can then be converted into biodiesel. As if that were not enough, the same microalgae can be very useful for purifying wastewater because the nitrogen and phosphorus in them can also be used to feed the microalgae.

In the Nordic countries of Europe, however, the use of microalgae is very limited: this environment is in fact characterized by very long winters with the sun peeping out much less often than in the regions further south and this causes significant problems in the use of microalgae. The researcher shows, in her study, that in such contexts using native strains of Nordic microalgae can be the solution.

“My work has shown that local Nordic microalgae are much better than standard varieties. Our Nordic strains are currently tested under “real conditions” with the aim of extending the growth period until late autumn or even winter,” says the researcher.