Houses made of high-tech wood could help us stay cool and also reduce carbon emissions by cutting energy used on air conditioning.

Liangbing Hu at the University of Maryland and his colleagues created the material by removing the lignin—a component of the cell walls in trees—from natural wood using hydrogen peroxide.

Read more: Our wooden future: making cars, skyscrapers and even lasers from wood

The remaining wood is mostly made of cellulose, another component of plant cell wall. Cellulose reflects visible light and only absorbs very low levels of near-infrared light. This means the cooling wood reflects most of the components of sunlight right back to the environment. As a result, a building made from this material would transmit barely any heat indoors.

The team also found that the material can absorb heat produced indoors, which is emitted at a different wavelength range to sunlight. During cooler nights, the wood helps release the heat outside, making it useful day and night.

Hu says the cooling wood is very dense and has a tensile strength of around 404 megapascals, making it 8.7 times stronger than natural wood and comparable to metal structure materials including steel.

To investigate how much energy the wood could save, the team simulated replacing the exterior walls and the roofs of some apartment buildings in 16 US states, representing a variety of climate conditions. They found the wood could reduce cooling energy requirements by an average of 20 to 35 per cent.

However, because cooling wood prevents heat from the sun from getting indoors, it will result in additional heating costs in winter. Therefore, Hu says the material is best suited for warm areas with long summers and short winters, such as Arizona and Hawaii.

It takes a few months of crawling until babies can stand up on their own and this might be true for some dinosaurs too. A fossil analysis has found a dinosaur that may have walked on all fours as a child and then shifted to two legs once it grew up.

Humans are probably the only animals today that transition from moving on all fours to two feet only during their lifetime, says Andrew Cuff at the Royal Veterinary College in Hertfordshire. “Finding another example, especially in an extinct and very different group like dinosaurs, is exciting,” he says.

Mussaurus patagonicus lived about 200 million years ago in present day Argentina. An adult M. patagonicus had a long neck and tail, and could reach 1 tonne in body weight. However, a newly hatched M. patagonicus was as tiny as a newborn chick, weighing only about 60 grams.

To see whether the animal’s body posture changed with its size, Cuff and his colleagues used M. patagonicus fossils to reconstruct 3D models of the dinosaur at three life stages: hatchling, one-year-old juvenile, and adult.

One feature that determines whether an animal can walk primarily on two feet is its centre of gravity. The point has to be above its two hindlegs rather than further forward.

The team found as a hatchling, M. patagonicus’s centre of gravity was located in the middle of its back, in front of the legs, meaning hatchlings had to stand on all fours in order to remain balanced.

As M. patagonicus became bigger its centre of gravity gradually shifted towards the rear, with its tail playing a large role.Ěý An adult M. patagonicus’s centre of gravity was very close to its hips above its legs, and could therefore walk bipedally.

“A change in posture through growth is incredibly uncommon,” says Cuff. A previous study has found an even earlier prosauropod, Massospondylus, might also go through the same transition. Yet, it’s unclear whether this is a common trend among dinosaurs.

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Fish living in the deep ocean have evolved highly-sensitive eyes that can see a range of colour hues in the near-darkness.

“It’s a big surprise,” says Zuzana Musilova at the University of Basel in Switzerland. “They have more sensitive eyes and can see way better than humans in lower light.”

Musilova and her colleagues collected DNA from 26 species of fish that live more than 200 metres below sea-level. Analysing this DNA, the team found that six species carried additional genes for rod opsin – the light-sensitive protein that enables the retina’s rod cells to detect light.

Vertebrate animals use rod opsin to detect light in dim environments, but most species – including humans – only have one rod opsin gene. However, adult silver spiny fins (Diretmus argenteus) – a flat fish that lives at depths down to 2,000 meters— has 38 of them.

The team translated these genes into proteins in a dish and shone lights of different wavelengths onto them, to see how they’d respond. They found that that these opsins detect a wide range of colours, and are especially sensitive to green and blue light.

“We believe they can detect more shades of blue and green than us,” Musilova says.

Musilova says having highly sensitive eyes may be useful for detecting the glowing bioluminescence emitted by many deep-sea creatures.

These bioluminescent lights are mostly blue and green in colour. Being able to tell colours apart could help fish distinguish whether a flash comes a predator or prey, Musilova says.

A robotic surgical device has learned to autonomously navigate inside a beating heart. Using only a small camera for vision, it successfully travelled to the correct location in the hearts of pigs for surgeons to then complete the operation.

Pierre Dupont at Harvard Medical School in Boston and his colleagues created a robotic catheter —a thin tube widely used in surgeries to deliver devices or drugs. The device has a camera and LED light on its tip and is connected to a motor system that controls its movement from the other end.

The team used 2000 images of the interior of a heart to train an algorithm to control the movement of the catheter. They then tested the device in five pigs with leaky heart implants needing to be sealed.

At the start of each procedure a doctor cut an incision in the bottom of the heart. The catheter was then inserted and tasked with autonomously navigating to the location of the leak, which it was given relative to other parts of the heart.

In each operation, the team tested the navigational skills of the catheter multiple times, and each pig had around three leaks that needed fixing. Out of 83 trials, the catheter successfully navigated to the right location 95 per cent of the time. A surgeon then took over to fix the leak.

It’s success rate is comparable to an experienced clinician, says Dupont. By taking over the mundane task of reaching the leaks, the robotic catheter lowers the mental burden of doctors so they can focus on plugging the holes, he says.

Currently, to fix a leaky valve implant, doctors use visual clues given by ultrasound and what they feel with their hands to navigate a catheter. “This requires significant skill and experience, and technology makes it easier,” says Manesh Patel at Duke University in North Carolina.

He hopes the autonomous catheter can be improved so it can enter the heart through blood vessels rather than a direct incision. Reaching the heart through vessels avoids unnecessary damage to the heart tissues, and doctors already do this manually, he says.