【推荐2】The world's elderly population is increasing. The number of old people, those who are aged 60 years or older, is expected to more than double in 2050 and is growing faster than the number of all younger age groups across the globe. This trend comes with an increasing demand for caregivers who are able to provide 24-hour care, not only at hospitals or nursing homes, but also at private homes and apartments.

Robotic assistants are expected to become increasingly marketable and reach 450.000 by 2045 because of the expected caregiver shortage in the United States. But Professor Ramses Martinez says, "Unfortunately, the outside hard structure（结构）of recent care-giving robots prevents them from getting along well with each other safely. After all, would you leave old people who are physically or mentally ill in the hands of a robot?"

Recent advances in material science have enabled the fabrication （制造)of robots with bodies that have the ability to reshape themselves when touched. But the complex design, fabrication, and control of soft robots recently hamper people from commercializing this technology and using them at home.

Martinez and the colleagues have developed a new design method that may enable the quick design and fabrication of soft robots using a 3D printer. The design process needs a few steps. First, a user makes a computer-aided design (CAD)file with the shape of the robot. The user then paints the CAD file to show which directions the different joints of the soft robot will move at. Finally a fast computer program takes a few seconds to change the CAD model into a 3D architected soft machine printed by a 3D printer. The architected soft robots move like humans, except that instead of muscles（肌肉）， they rely on tiny motors that pull ropes tied to the ends of their hands and legs. They can be squeezed and pulled to more than 900 percent of their initial length. "They can perform complex movements with ease, and this work makes a step forward toward the development of autonomous soft robots." Martinez says. The technology is patented. The researchers are looking for partners to test and commercialize their technology.

【推荐3】Minh Anh Ho is sitting beside a microscope. Many people are busy with other tasks. One is interviewing the mayor for a TV news station. Another is running the electric company. As a researcher for a company that repurposes plastic, Minh Anh Ho is studying a sheet of cling wrap (保鲜膜). “It’s a really important job,” she says. “Plastic takes a really long time to disappear, so it would be good to come up with something else to do with it and not just throw it away.”

The learning center where Minh Anh Ho and her class are spending their day is designed to introduce kids to working life. Students run an imaginary town, with each kid doing a different job in a different business. Each year, about 83% of all sixth graders in Finland go through the program. It teaches them not just about business and working, but also, as Minh Anh Ho’s “job” makes clear, about the circular (循环) economy.

Most societies have linear (线性) economies, which operate on a “take, make, waste” model. Natural resources are taken from the Earth and made into products, which are usually thrown away if left over. In 2016, Finland became the first country to use a “road map” to a circular economy. This model focuses on the transformation of existing products. Businesses rely on recycled or repurposed materials and use less raw (未经加工的) material to make their products. That reduces the amount of waste going into landfills.

Education has always been a central part of Finland’s plan. Kindergarten director Liisa Woitsch is sitting on the floor with students and a broken wooden chair. “Do we just throw it away now,” she asks, “or can you think of anything else that can be done with it?” A little boy pounds on the chair. He says it can be used as a drum.

Anssi Almgren helped design the program. “Children have so many great ideas,” he says. “We want to enable them to think about solutions. But changing a society by educating its youth takes time.”

【推荐3】A new type of plastic made directly from organic plant waste has been created by scientists. The new material is easy to make and could be used in everything from packaging and textiles (纺织品) to medicine and electronics.

The researchers in Switzerland have already used the technique to make packaging films, fibres that can be used for clothes or other textiles and threads for 3D printing.

Conventional plastic is so widespread because making it combines low cost, heat stability, mechanical strength and processability, the researchers say. Until now, few, if any, alternative plastics have managed to match or surpass conventional plastic in these aspects, which is vital if they are to be used more widely.

To make the plastic, scientists “cooked” wood and other plant waste in inexpensive chemicals to make a plastic precursor (前身). The sugar structure stays complete within the molecular (分子) structure of the plastic, making the chemistry much cheaper than other types of alternative plastic.

Back in 2016, the researchers found out that if they added an aldehyde (乙醛) chemical they could stabilize parts of the plant material to avoid their destruction during extraction. But now, they are using glyoxylic acid, a solid organic substance that occurs naturally and is used in industry. The team could simply fasten “sticky” groups onto both sides of the sugar molecules, which allowed them to act as plastic building blocks. Using this simple technique, they could turn up to a quarter of the weight of agricultural waste, or 95 percent of purified sugar into plastic.

“The plastic has very exciting properties, notably for applications like food packaging,” Professor Jeremy Lautenbacher from the Swiss Federal Institute of Technology, who created the plastic, said. “What makes the plastic unique is the presence of the complete sugar structure. This makes it incredibly easy to make because you don’t have to change what nature gives you, and it is simple to break down because it can go back to a molecule that is already plentiful in nature.”