1 . A living robot has been created out of frog skin cells. Xenobots, named after the frog species Xenopus laevis that the cells come from, were first described last year. Now the team behind the robots has improved their design and demonstrated new capabilities.
To create the xenobots, Michael Levin at Tufts University in Massachusetts and his colleagues obtained tissue from 24-hour-old frog embryos after very small physical operation. Where the previous version relied on the contraction of heart muscle cells to move them forward by pushing off surfaces, these new xenobots swim around faster. They also live between three and seven days longer than their previous generation, which only lasted about seven days, and have the ability to sense their surroundings to some extent, turning red when exposed to blue light.
“The fundamental finding here is that when you free skin cells from their normal context, and you give them a chance to build other things than what they normally build,” says Levin. “To me, one of the most exciting things here is that they are plastic. This idea that even normal cells, not genetically modified, are in fact capable of building something completely different.”
Because they are created from cells, the xenobots eventually break apart and are totally biodegradable, says team member Douglas Blackiston, also at Tufts University. He therefore hopes that they can be used for biomedical and environmental applications.
Previous attempts at creating living robots, such as a wirelessly controlled cockroach, have involved dealing with live animals, raising ethical concerns. Xenobots differ from these because they are made entirely of living cells. “The approach here is maybe ethically the least problematic because everything starts with cells. They have no neurons, so it's not an animal,” says Auke ljspeert at the Swiss Federal Institute of Technology at Lausanne, who wasn't involved in the research. “It's really cells, so I find it maybe the cleanest way."
1. How were the new xenobots created?| A．By making use of frog embryos. | B．By relying on heart muscle cells. |
| C．By sensing similar surroundings. | D．By exposing them to blue light. |
| A．Fragile. | B．Stable. | C．Flexible. | D．Active. |
| A．The xenobots can't break down easily. | B．The xenobots need to be further perfected. |
| C．The xenobots can be applied in other fields. | D．The xenobots have already been widely used. |
| A．The new approach starts with some neurons. |
| B．Xenobots have raised least ethical concerns. |
| C．The wireless controlled cockroach is a failure. |
| D．Previous living robots involve few living animals. |
2 . Brain games do not make you smarter. Companies like Lumosity made their bones throwing around terms like "brain elasticity'' to publicize their specific brand of brain promoting training, but upon further review, their claims were a bit dubious. They paid the price in the form of a $2 million false advertising fine, but their misstep doesn't mean there's no daily avenue to higher cognitive（认知的）function.
For kids, the best way to help improve cognitive function is through aerobic exercise. For adults, the best bet is more sedentary, and fortunately a bit less intense; if you want to up your energy and brain function, take some time out of your day to practice Hatha yoga or mindfulness meditation（冥想）.
A new study from the University of Waterloo took a look at the effects of 25 minutes of daily Hatha yoga or mindfulness meditation on brain function and energy in a group of 31 adults. The participants were asked to complete 25 minutes of quiet reading as a control activity and 25 minutes of varied meditation at random intervals. Following each activity, the participants were asked to perform a task which would measure their brain function and energy level.
The research found that following both meditation and Hatha yoga, participants would perform significantly better at the task. The participants who practiced Hatha yoga saw the most sizeable bump in performance.
“There are a number of theories about why physical exercises like yoga improve energy levels and cognitive test performance,” said Kimberly Luu, the study’s lead author, via Science Daily. "These include the release of endorphins, increased blood flow to the brain, and reduced focus on ruminative thoughts. Though ultimately, it is still an open question.”
Twenty-five minutes of Hatha yoga in exchange for higher cognitive function? Not bad at all.
1. What does the underlined word "dubious" in paragraph 1 mean?| A．Acceptable. | B．Trustful. | C．Reasonable. | D．Doubtful. |
| A．To help improve cognitive function through physical exercises. |
| B．To test the effects of daily exercise on energy and brain function. |
| C．To measure participants’ cognitive performance and energy levels. |
| D．To increase blood flow to the brain and reduce focus on thoughts. |
| A．They are rarely built on a theoretical basis. |
| B．They attract people's attention to open questions. |
| C．They are beneficial to brain function and energy. |
| D．They lower people's levels of cognitive performance. |
| A．Daily Exercise Promotes Brain Power. |
| B．Brain Function Is Related to Energy. |
| C．A New Study Changes People's Mind. |
| D．Brain Power Controls Cognitive Performance. |
