What will power your house in the future？Nuclear, wind, or solar power？According toscientists at the Massachusetts Institute of Technology(MIT)in the US, it might beleaves—but artificial(人造的)ones.

    Natural leaves are able to change sunlight and water intoenergy. It is known as photosynthesis(光合作用). Nowresearchers have found a way to imitate this seemingly simple process.

    The artificial leaf developed by Daniel Nocera and hiscolleagues at MIT can be seen as a special silicon chip with catalysts(催化剂). Similar tonatural leaves, it can splitwater into hydrogen and oxygen when put into a bucket of water. The hydrogenand oxygen gases are then stored in a fuel cell, which usesthose two materials to produce electricity, located eitheron top of a house or beside the house.

Though the leaf is only about the shape of a poker card, scientistsclaimed that it is promising to be an inexpensive source of electricity indeveloping countries.“ One can imagine villages in India and Africa not longfrom now purchasing an affordable basic power system based on this technology, ”said Noceraat a conference of the American Chemical Society.

    The artificial leaf is not a new idea. The first artificial leafwas invented in 1997 but was too expensive and unstable for practical use. Thenew leaf, by contrast, is made ofcheap materials, easy to useand highly stable. In laboratory studies, Nocera showedthat an artificial leaf prototype(原型)could operatecontinuously for at least 45 hours without a drop in activity.

    The wonderful improvements come from Nocera's recent discoveryof several powerful, new andinexpensive catalysts. These catalysts make the energy transformation insidethe leaf more efficient with water and sunlight. Right now, the new leafis about 10 times more efficient at carrying out photosynthesis than a naturalone. Besides, the device canrun in whatever water is available；that is, it doesn'tneed pure water. This is important for some countries that don't have access topure water.

    With the goal to “make each home its own power station” and“give energy to the poor”, scientistsbelieve that the new technology could be widely used in developing countries, especially inIndia and rural China.

    You get anxious if there's no wi-fi in the hotel or mobile phone signal up the mountain. You feel upset if your phone is getting low on power and you secretly worry things will go wrong at work if you're not there. All these can be called “always on” stress caused by smart phone addiction.

    For some people, smart phones have set them free from the nine-to-five work. Flexible working has given them more control over their working lives and enabled them to spend more time with their friends and families. For many others though, smart phones have become cruel masters in their pockets, never allowing them to turn them off and relax.

    Pittsburgh-based developer Kevin Holesh was worried about how much he was ignoring his family and friends in favor of his iPhone. So he developed an app — Moment — to monitor his usage. The app enables users to see how much time they're spending on the device and set up warnings if the usage limits are broken. “Moment's goal is to promote balance in your life,” his website explains. “Some time on your phone, some time off it enjoying your loving family and friends around you.”

    Dr. Christine Grant, an occupational psychologist at Coventry University, said, “The effects of this ‘always on' culture are that your mind is never resting, and you're not giving your body time to recover, so you're always stressed. And the more tired and stressed we get, the more mistakes we make. Physical and mental health can suffer.”

    And as the number of connected smart phones is increasing, so is the amount of data. This is leading to a sort of decision paralysis (瘫痪) and is creating more stress in the workplace because people have to receive a broader range of data and communications which are often difficult to manage. “It actually makes it more difficult to make decisions and many do less because they're controlled by it all and feel they can never escape the office,” said Dr. Christine Grant.

    If you could change your child's DNA in the future to protect them against diseases, would you? It could be possible because of technology known as CRISPR-Cas, or just CRISPR.

    CRISPR involves a piece of RNA, a chemical messenger, designed to work on one part of DNA; it also uses an enzyme (酶) that can take unwanted genes out and put new ones in, according to The Economist. There are other ways of editing DNA, but CRISPR will do it very simply, quickly, and exactly.

    The uses of CRISPR could mean that cures are developed for everything from Alzheimer's to cancer to HIV. By allowing doctors to put just the right cancer-killing genes into a patient's immune system, the technology could help greatly.

    In April scientists in China said they had tried using CRISPR to edit the genomes (基因组) of human embryos. Though the embryos would never turn into humans, this was the first time anyone had ever tried to edit DNA from human beings. With this in mind, the US' National Academy of Sciences plans to discuss questions about CRISPR's ethics (伦理问题).

    For example, CRISPR doesn't work properly yet. As well as cutting the DNA it is looking for, it often cuts other DNA, too. In addition, we currently seem to have too little understanding of what DNA gives people what qualities.

There are also moral questions around “playing God”. Of course, medicine already stops natural things from happening —— for example, it saves people from infections. The opportunities to treat diseases make it hard to say we shouldn't keep going.

    A harder question is whether it is ever right to edit human germ-line (种系) cells and make changes that are passed on to children. This is banned in 40 countries and restricted in many others. However, CRISPR means that if genes can be edited out, they can also be edited back in. It may be up to us as a society to decide when and where editing the genome is wrong.

    Also, according to The Economist, gene editing may mean that parents make choices that are not obviously in the best interests of their children: “Deaf parents may prefer their children to be deaf too; parents might want to make their children more intelligent at all costs.”

    In the end, more research is still needed to see what we can and can't do with CRISPR. “It's still a huge mystery how we work,” Craig Mello, a UMass Medical School biologist and Nobel Prize winner, told The Boston Globe. “We're just trying to figure out this amazingly complicated thing we call life.”

C

    There's a new frontier in 3D printing that's beginning to come into focus: food. Recent development has made possible machines that print, cook, and serve foods on a mass scale. And the industry isn't stopping there.

Food production

    With a 3D printer, a cook can print complicated chocolate sculptures and beautiful pieces for decoration on a wedding cake. Not everybody can do that — it takes years of experience, but a printer makes it easy. A restaurant in Spain uses a Foodini to "re-create forms and pieces" of food that are "exactly the same," freeing cooks to complete other tasks. In another restaurant, all of the dishes and desserts it serves are 3D-printed, rather than farm to table.

Sustainability(可持续性）

    The global population is expected to grow to 9.6 billion by 2050, and some analysts estimate that food production will need to be raised by 50 percent to maintain current levels. Sustainability is becoming a necessity. 3D food printing could probably contribute to the solution. Some experts believe printers could use hydrocolloids (水解胶体) from plentiful renewables like algae(藻类) and grass to replace the familiar ingredients(烹饪原料). 3D printing can reduce fuel use and emissions. Grocery stores of the future might stock "food" that lasts years on end, freeing up shelf space and reducing transportation and storage requirements.

Nutrition

    Future 3D food printers could make processed food healthier. Hod Lipson, a professor at Columbia University, said, "Food printing could allow consumers to print food with customized nutritional content, like vitamins. So instead of eating a piece of yesterday's bread from the supermarket, you'd eat something baked just for you on demand."

Challenges

    Despite recent advancements in 3D food printing, the industry has many challenges to overcome. Currently, most ingredients must be changed to a paste(糊状物) before a printer can use them, and the printing process is quite time-consuming, because ingredients interact with each other in very complex ways. On top of that, most of the 3D food printers now are restricted to dry ingredients, because meat and milk products may easily go bad. Some experts are skeptical about 3D food printers, believing they are better suited for fast food restaurants than homes and high-end restaurants.

    These days, it seems that almost all of us are too serious. My older daughter often says to me, "Daddy, you've got that serious look again." Even those of us who are committed to non-seriousness are probably too serious. People are frustrated and anxious about almost everything—being five minutes late, witnessing someone look at us wrong or say the wrong thing, paying bills, waiting in line, overcooking a meal, making an honest mistake -- you name it, and we all lose perspective（理性判断）over it.

    The root of being anxious is our unwillingness to accept life as being different, in any way, from our expectation. Very simply, we want things to be a certain way but they're not a certain way. Life is simply as it is. Perhaps Benjamin Franklin said it best: "Our limited perspective, our hopes and fears become our measure of life, and when circumstances don't fit our ideas, they become our difficulties." We spend our lives wanting things, people, and events to be just as we want them to be—and when they're not, we fight and we suffer.

    The first step in recovering from over-seriousness is to admit that you have a problem. You have to want to change, to become more easygoing. You have to see that your own anxiety is largely of your own creation—it's made up of the way you have set up your life and the way you react to it.

    The next step is to understand the link between your expectations and your frustration level. Whenever you expect something to be a certain way and it isn't, you're upset and you suffer. On the other hand, when you let go of your expectations, when you accept life as it is, you're free.

    A good exercise is to try to approach a single day without expectation. Don't expect people to be friendly. When they're not, you won't be surprised or bothered; if they are, you'll be delighted. Don't expect your day to be problem-free. Instead, as problems come up, say to yourself, "Ah, another barrier to overcome." As you approach your day in this manner you'll notice how elegant life can be. Rather than fighting against life, you'll be dancing with it. Pretty soon, with practice, you'll lighten up your entire life. And when you lighten up, life is a lot more fun.

    British chemist David Evans has become an overnight celebrity on Chinese social media. His chemistry experiments have attracted over 2 million followers in just a few months. Evans is a chemistry professor at the Beijing University of Chemical Technology. The 60-year-old always wears a white lab coat, a pair of safety goggles (护目镜), and smiles often. Some web users say he looks just like the “grandpa of KFC”.

    Evans has posted videos of various experiments. His most popular experiments have attracted millions of hits on video-sharing apps. Excited children's cheers and shouts can be heard in his videos. “I hope my experiments can arouse people's interest in science,” he says.

    Evans has been interested in China since childhood. In the early 1970s, before the reform and opening-up, he viewed it as a “country full of mysteries”. He first visited the Chinese mainland in 1987 to attend a chemistry conference in Nanjing, Jiangsu Province. He quit his job in the United Kingdom and moved to Beijing in 1996. Many of his friends thought he was crazy. But Evans says they just saw China's challenges but not its potential.

    Since 2011, Evans has turned to the Internet to popularize science. He learned short-video apps are also popular in small cities and rural areas. And he realized this enables him to reach more students, who lack opportunities to perform fun experiments. But even a one-minute video requires a considerable amount of work. Still, he thinks it's worth it to fulfill his responsibility to popularize science.

    His experiments always fill schools' lecture halls with laughter. Some viewers call him “a Harry Potter-like magician”, but he disagrees. “A magician never tells the secrets behind his tricks, but a scientist always gives an explanation.” He sees himself as a teacher. He performs experiments to spread knowledge, inspire thinking, remove misunderstandings and show that science can create change. Evans says he looks forward to more “chemical reactions” with China.