Genome-edited(基因编辑) food made with CRISPR-Cas9 technology is being sold on the open market for the first time. Since September, the Sicilian Rouge tomatoes, which are genetically edited to contain high amounts of Y-aminobutyric acid(γ-氨基丁酸)(GABA), have been sold direct to consumers in Japan by Tokyo-based Sanatech Seed. The company claims oral intake of GABA can help support lower blood pressure and promote relaxation.

“In Japan, dietary supplements and foods enriched for GABA are popular among the public, ”says Hiroshi Ezura, chief technology officer at Sanatech. “GABA is a famous health-promoting compound in Japan. It’s like vitamin C,” he says. More than 400 GABA-enriched food and beverage products, such as chocolates, are already on the Japanese market. “That’s why we chose this as our first target for our genome editing technology,” he says.

Sanatech, a startup from the University of Tsukuba, first tested the appetite of consumers in Japan for the genome-edited fruit in May 2021 when it sent free seedling CRISPR-edited tomato plants to about 4,200 home gardeners who had requested them. Encouraged by the positive demand, the company started direct internet sales of fresh tomatoes in September and a month later took orders for seedlings for next growing season. Japan’s regulators approved the tomato in December 2020.

Since its beginning a decade ago, CR1SPR-Cas9 genome editing has become a tool of choice for plant bioengineers. Researchers have successfully used it to develop non-browning mushrooms, drought-tolerant soybeans and a host of other creative traits in plants. Many have received a green light from US regulators. But before Sanatech’s tomato, no CRISPR-edited food crops were known to have been commercialized.

Consumers may find food ingredients made with some of the older DNA editing techniques. Indeed, Calyxt in 2019 commercialized a TALEN-edited soybean oil that is free of trans fats. So it was only a matter of time before a CRISPR-edited crop reached palates.

Compared with solar and wind energy, which are booming, tidal (潮汐的) power is a loser in the clean-energy competition. But if you did want to build a tidal power station, there are few better sites than the mouth of the River Severn, in Britain. Its tidal range, the difference in depth between high and low tides, of around 15 metres is among the largest in the world.

Engineers and governments have been toying with the idea since at least 1925. But none of the suggested projects has materialised. Price is one objection. A study thought that tidal energy might cost between ￡216 and ￡368 ($306-521) per MWh of electricity by 2025, compared with ￡58-75 for seagoing wind turbines (轮机) and ￡55-76 for solar panels. Environmentalists also worry that any plant would change the tides, making life harder for wildlife.

An engineer called Rod Rainey thinks he has a way around both problems. He plans to replace the conventional turbines of previous plans with a much older technology. Specifically, he plans to span (横跨) the river mouth with a line of water wheels. This is a design that dates back to the early days of the Industrial Revolution. Examples can be found fixed to the sides of old watermills (水磨).

But there would be nothing old-fashioned about Mr Rainey’s wheels. Thirty metres high and sixty wide, they would be made from ordinary steel. Two hundred and fifty of them, along with the supporting structures, would be floated into place and secured to the seabed, creating a line 15km long. Together, they could supply power at an avenge ate of 4GW. That is about as much as two biggish nuclear power stations would manage. Substituting one of the wheels with a set of locks would provide a shipping channel about twice the width of Panama Canal, permitting upstream ports such as Avonmouth and Cardiff to continue operating.

Airbus is testing a big harpoon(鱼叉) to trap rogue (流氓) or unnecessary satellites and pull them out of the sky. The 1m-long projectile(自动推进武器) would be attached to a chase spacecraft through a strong chain. Once the target was captured and under control, the chase vehicle would then drag its prey down into the atmosphere to burn to destruction.

Airbus has been working on the concept for a number of years now, developing ever bigger systems. It is a response to the growing problem of orbital junk—old pieces of hardware that continue to circle the globe and which now cause a collision threat to working satellites.

Something in the region of 20,000 items of 10cm or larger are currently being tracked. The latest Airbus harpoon is being designed with the capability to capture one of the biggest rogue items—Europe’s defunct Envisat (欧洲环境卫星)，which is now a rubbish satellite. “This 8-tonne monster died suddenly in orbit in 2012”，explained advanced project engineer Alastair Wayman.

The testing at the aerospace company’s facility in Stevenage, UK, involves firing the harpoon, using compressed air(压缩空气), into a panel that is representative of the kinds of material used to build satellite structures. “The harpoon goes through these panels like a hot knife through butter,” said Mr Wayman.

A harpoon is relatively simple. You line up the target and shoot. Whereas, with the harpoon, all you have to do is to sit a distance away, wait for the target to spin underneath you, and at the right moment fire your harpoon.