Mom and I were putting the finishing touches on dinner, and my little niece Jessica came in to set the table. Instead of going to the dish cabinet, she went into the pantry where there was a stack of old, mismatched dinner plates on the bottom shelf.

When she had set all six plates, she stood back and sighed, “Oh, Grandma, your plates are so beautiful. Ours are all alike!” We had a good laugh at her innocent remark, but as I think back to all those years ago, I believe she was right. Those plates were beautiful.

Mom worked for the local Council on Aging as a housekeeper. She did many of the little things that allowed elderly people to stay in their own homes. Most of her clients got Meals on Wheels, a service in the 1970s. They received a hot lunch and a cold snack to have later in the evening. This is really not very much food. Every evening Mom would make to-go meals on these mismatched plates covered with aluminum foil, and then deliver them to the people who she knew didn’t get enough to eat.

This was about ten years before microwave ovens became common, so it was important that the food be on a plate that could be reheated in a regular oven. Instead of a cold sandwich and macaroni salad, Mom’s clients dined on Beef Manhattans, pan-fried chicken or meatloaf, along with veggies and a piece of pie or cake. Mom and Dad did this even after Mom left her job, and Mom continued after Dad’s death until all her former clients had either passed away or moved out.

When I was cleaning our Mom’s house after her death, I kept one as a souvenir. That plate is a sweet reminder of the lessons of generosity and caring for one’s neighbor that were modeled for me by my parents.

More than half of the world’s population live in cities, and by 2050 the UN expects that proportion to reach 68%. This means more homes, roads and other infrastructure. In India alone, a city the size of Chicago will have to be developed every year to meet demand for housing. Such a construction increase is a bad sign for dealing with climate change, because making steel and concrete, two of the most common building materials, generates around 8% of the world’s CO₂ emissions (排放). If cities are to expand and become greener at the same time, they will have to be made from something else.

Wood is one of the most promising sustainable alternatives to steel and concrete. It is not, however, everyday wood that is attracting the interest of architects.

Rather, it is a material called engineered timber. This is a combination of different layers, each designed to meet the requirements of specific parts such as floors, panels and beams (横梁). Designers can use it to provide levels of strength like steel, in a product that is up to 80% lighter. In addition, engineered timber is usually made into large sections in a factory for future use, which reduces the number of deliveries to a construction site.

According to Michael Ramage of the University of Cambridge, a wooden building produces 75% less CO₂ than a steel and concrete one of the same size. However, if building with wood takes off, it does raise concern about there being enough trees to go round. But with sustainably managed forests that should not be a problem, says Dr Ramage. A family-sized apartment requires about 30 cubic meters of timber, and he estimates Europe’s sustainable forests alone grow that amount every seven seconds. Nor is fire a risk, for engineered timber does not burn easily. Besides, fireproofing layers can be added to the timber. All in all, then, it looks as if wood as a building material may get a new lease of life.

In Judgement Day, one of the hit film series Terminator, a cyborg(生化人) played by Schwarzenegger could heal his skin wound magically, that is, he makes the skin repair itself in less than a second. Recently, according to Mirror, a smart electronic skin like it has been developed, which is as strong, stretchy and sensitive as humans'.

Previous attempts to "electronically" copy human skin have fallen short. Making suitably flexible electronics that can perform delicate tasks while also putting up with the bumps(碰撞) and scrapes of everyday life is challenging. The previous sensor layer was too weak or too strong, reducing its sensitivity or flexibility, which makes it more likely to break.

With the development of 2D sensors and hydrogel(水凝胶), scientists' efforts paid off, linking sensor layer with skin functionally. Study author Dr Jie Shen said, "Hydrogels are more than 70 percent water, making them very compatible(相容的) with human skin tissues. We created the sensor layer that remained complete even when the material was stretched to 28 times its original size.

This e-skin can sense temperature and touch from up to 8 inches away, react to things in under one tenth of a second and repair itself more than 5,000 times. The new invention could help monitor a range of biological information, including changes in blood pressure. While the first application is medical, the e-skin could benefit a wide range of products one day, such as monitoring the structural condition of furniture and planes.