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Made from human cardiac cells, biohybrid fish swims by recreating pumping heart’s contractions

ScientiFix, our weekly feature, offers you a summary of the top global science stories of the week, with links to their sources.

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New Delhi: In a first, researchers from Harvard University have developed a fully autonomous biohybrid fish from human heart cells. 

The artificial fish swims by recreating the muscle contractions of a pumping heart. This advance brings researchers a step closer to developing a more complex artificial muscular pump and providing a platform to study heart diseases like arrhythmia.

The ultimate goal is to build an artificial heart to replace a malformed heart in a child

The device was inspired by the shape and swimming motion of a zebrafish. This biohybrid — combining biological and other components — zebrafish has two layers of muscle cells, one on each side of the tail fin. When one side contracts, the other stretches. That stretch triggers the opening of a protein channel, which causes a contraction, which then triggers a stretch, and so on, leading to a closed loop system that can propel the fish for more than 100 days. 

The researchers also engineered an autonomous pacing node, like a pacemaker, which controls the frequency and rhythm of these spontaneous contractions. Together, the two layers of muscle and the autonomous pacing node enabled the generation of continuous, spontaneous, and coordinated back-and-forth fin movements.

The biohybrid fish also improves with age. Its muscle contraction amplitude, maximum swimming speed, and muscle coordination all increased for the first month as the cardiomyocyte cells matured.  Eventually, the biohybrid fish reached speeds and swimming efficacy similar to zebrafish in the wild. 

Next, the team aims to build even more complex biohybrid devices from human heart cells. Read more

NASA’s Parker Solar Probe takes first visible light images of Venus surface 

NASA’s Parker Solar Probe has taken its first visible light images of the surface of Venus from space.

Venus’s surface is usually shrouded from sight because its atmosphere is full of thick clouds. But in two recent flybys of the planet, the Parker probe used its Wide-Field Imager to capture the entire nightside in wavelengths of the visible spectrum the type of light that the human eye can see.

The images, combined into a video, reveal a faint glow from the surface that shows distinctive features like continental regions, plains, and plateaus. A halo of oxygen in the atmosphere can also be seen surrounding the planet.

Such images of the planet, often called Earth’s twin, can help scientists learn more about Venus’s surface geology, what minerals might be present there, and the planet’s evolution. Given the similarities between the two planets, this information can help scientists understand why Venus became inhospitable and Earth became an oasis. Read more

Also read: ‘X’ particles found at CERN & artificial intelligence identifies hidden meteorites in Antarctica

Perseverance Mars rover sets record for longest drive in Martian day

NASA’s Perseverance Mars rover has set a new record for the longest drive completed in a single Martian day. 

On 4 February, the rover travelled 245.76 metres on the surface. 

The previous record was held by NASA’s Opportunity rover, which traversed 214 metres in a single day in 2005.

Perseverance had previously been at the same position for several weeks after collecting rock samples from the Martian surface, which had temporarily choked a rover part.

With this problem resolved, the rover is now doing some last-minute scouting before attempting a multi-kilometre drive to a nearby delta.

Deltas are areas where water once flowed, which could provide a rich environment for the rover’s ultimate mission to collect samples that could have hosted ancient microbes. Read more

Black Death mortality may not have been as widespread as thought

The Black Death, the most infamous pandemic in history, which plagued Europe, West Asia and North Africa from 1347 to 1352, is estimated to have wiped out up to 50 per cent of Europe’s population. 

The pandemic transformed religious and political structures, precipitating major cultural and economic transformations such as the Renaissance. 

However, a new study by an international group at the Max Planck Institute for the Science of Human History in Jena, Germany, has found that the plague’s mortality in Europe was not as widespread as long thought. 

Researchers analysed pollen samples from 261 sites in 19 modern-day European countries to determine how landscapes and agricultural activity changed between 1250 and 1450 CE from roughly 100 years before to 100 years after the pandemic. 

Their analysis supports the devastation experienced by some European regions, but also finds that the Black Death did not impact all regions equally.

Human activities such as farming or clearing native plants for building can shape the landscape — and these activities were heavily dependent on the availability of rural workers. 

The team analysed 1,634 pollen samples from sites all over Europe to see which plants were growing in which quantities, and thereby determine whether agricultural activities in each region continued or halted, or if wild plants regrew while human pressure was reduced.

Their results show that the plague’s mortality varied widely, with some areas suffering the devastation the plague is known for, and others experiencing a much lighter touch. 

Sharp agricultural declines in Scandinavia, France, southwestern Germany, Greece and central Italy support the high mortality rates attested in mediaeval sources. Meanwhile, many other regions, including much of Central and Eastern Europe, and parts of Western Europe including Ireland and Iberia, show evidence of continuity or uninterrupted growth. Read more

Ancient supermountains may have shaped evolution on Earth

Scientists have found that giant mountain ranges at least as high as the Himalayas and stretching up to 8,000 kilometres across entire supercontinents played a crucial role in the evolution of early life on Earth.

A team from The Australian National University (ANU) tracked the formation of these supermountains throughout Earth’s history using traces of zircon with low lutetium content – a combination of mineral and rare earth element found only in the roots of high mountains where they form under intense pressure. 

The study found that these supermountains formed only twice in Earth’s history the first between 2,000 and 1,800 million years ago, and the second between 650 and 500 million years ago. Both mountain ranges rose during periods of supercontinent formation.  

To give you an idea of the scale: The entire length of the Himalayas would have to be repeated three to four times to reach the length of these ancient mountain ranges. 

The first range, the Nuna Supermountain, coincides with the likely appearance of eukaryotes organisms that later gave rise to plants and animals. 

The second, known as the Transgondwanan Supermountain, coincides with the appearance of the first large animals 575 million years ago and the Cambrian explosion 45 million years later, when most animal groups appeared in the fossil record.

When the mountains eroded, they provided essential nutrients such as phosphorus and iron to the oceans, supercharging biological cycles and driving evolution to greater complexity.  The supermountains may also have boosted oxygen levels in the atmosphere, needed for complex life to breathe. 

The time interval between 1,800 and 800 million years ago is known as the Boring Billion, because there was little or no advance in evolution. The slowing of evolution is attributed to the absence of supermountains during that period, reducing the supply of nutrients to the oceans. Read more

(Edited by Rohan Manoj)

Also read: Scientists find world’s oldest flower bud fossil, and China makes ‘artificial moon’ on Earth


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