Could blood shortages become a thing of the past? Bacterial enzymes (W) from the human gut (肠,内脏)turn type A blood into the type universally accepted for transfusions, and do it more efficiently than current methods.
Our blood comes in four main varieties: A, B, AB and O. The red blood cells in each type are similar in shape, but they have different sugars on their surfaces. Red blood cells in type A host a particular set of these sugars, with type B having a different set. AB blood cells carry both A and B sugars and type O cells have none.
These sugars can act as antigens(抗原),causing an immune response. For instance, transfusing type B blood into someone with type A can cause death. That is what makes anyone with type O blood a universal donor: there are none of these antigens. So being able to remove these sugars from A, B and AB type blood would be helpful, effectively making it usable in transfusions for all.
"We knew that those same sugars that are on our red blood cells are also produced on the inside of the gut wall," says Steve Withers at the University of British Columbia, Canada. So he and his colleagues started searching for bacteria in human waste (粪便)that might make enzymes that let them feed on and break down gut wall sugars.
Analyzing bacterial genes, they found a family of enzymes that help gut bacteria harvest the sugars. When the team combined the enzymes with type A blood, the sugars were removed from the blood cells, resulting in type O blood. The process is 30 times more efficient than an existing one involving other enzymes.
The bacterial enzymes will have to go through more safety testing before they can be used in blood for human transfusions, but it is a promising step, says Withers. He presented the work at a meeting of the American Chemical Society in Boston this week.
1. Why is a man with type O blood a universal donor?A.The similar shape of his red blood cells. |
B.No sugars on his red blood cells. |
C.Different sugars on the blood cells. |
D.Different quantity of his red blood cells. |
A.By analyzing bacteria genes. |
B.By combining the enzymes with blood. |
C.By removing the enzymes from the cells. |
D.By involving different enzymes in blood. |
A.Fashion and Lifestyle. |
B.Finance and Business. |
C.Travel and Sports. |
D.Medicine and Health. |
相似题推荐
【推荐1】A quiet space is often considered essential for achieving the concentration that leads to academic success. But research shows that some students may benefit from breaking the silence with certain kinds of music while they study. Music has a powerful influence on both the body and the brain, in ways that can help students navigate the physical and emotional barriers that come with academic challenges.
One U.S. study compared students who took a test to soft music with those who took the test under silent conditions. The study found that students taking a test to music not only completed more questions within a set time but also answered more questions correctly. Music has been further linked to improvements in memory and recall. Experts have found that when music stimulates mood and motivation, students are able to learn more and to better demonstrate their knowledge.
A bit of mood music affects more than just memory and recall when students hit the books. Music can also relieve stress associated with school. Scientists have learned that music engages the autonomic nervous system, which not only controls the unconscious functions of the body but also influences emotions. So it’s no surprise that researchers from the Group Health Research Institute concluded that certain kinds of background music can be just as effective at reducing stress as a massage. Furthermore, while the brain feels better with music, the body may as well. Research shows that certain types of music can make physical pain feel less intense. What’s more, calming music with a steady, meditative (冥想的) rhythm can help people sleep longer and more deeply.
However, some educators express concern that listening to music while trying to concentrate may do more harm than good. Loud music may have a negative influence on a student’s mood or act as a distraction. Actually, the best approach may depend on the students themselves. Listening to music during study time may not mean a guaranteed A for all students, but those who find it helpful should be allowed to plug in their headphones.
1. What does the underlined word “navigate” in the first paragraph probably mean?A.Recognize. | B.Assess. | C.Overcome. | D.Create. |
A.present the effects of music on mind and body |
B.compare the functions of different types of music |
C.confirm the impacts of music on memory and recall |
D.give examples of the influences of music on emotions |
A.Music helps students remove physical pain immediately. |
B.Loud music has the same calming effect as a massage. |
C.Listening to music makes it easier for students to multitask. |
D.Music is likely to better students’ academic performance. |
A.The Power of Silence | B.The Score to Better Scores |
C.Music to a Sharper Mind | D.Road to Academic Success |
【推荐2】Scientists have found further evidence that dolphins call each other by "name".
Research has revealed that the marine mammals use a unique whistle to identify each other. A team from the University of St-Andrews in Scotland found that when the animals hear their own call played back to them, they respond.
Dr. Vincent Janik, from the university's Sea Mammal Research Unit, said, "Dolphins live in this three-dimensional (三维) environment, offshore without any kind of landmarks and they need to stay together as a group. These animals live in an environment where they need a very efficient system to stay in touch. "
It had been long suspected that dolphins use distinctive whistles in much the same way that humans use names. Previous research found that these calls were used frequently, and dolphins in the same group were able to learn and copy the unusual sounds. But this is the first time that the animals' response to being addressed by their "name" has been studied. To investigate, researchers recorded a group of wild bottlenose dolphins, capturing each animal's signature sound. They then played these calls back using underwater speakers.
“We played signature whistles of animals in the group; we also played other whistles in their repertoire (曲目) and then signature whistles of different populations-animals they had never seen in their lives," explained Dr. Janik.
The researchers found that individuals only responded to their own calls, by sounding their whistles back. The team believes the dolphins are acting like humans: when they hear their names, they answer.
Dr. Janik said this skill probably came about to help the animals to stick together in a group in their vast underwater habitat. He said, "Most of the time they can't see each other, they can't use smell underwater, which is a very important sense in mamma is tor recognition, and they also don't tend to hang out in one spot, so they don't have nests or burrows that they return to.”
1. How can the marine mammals distinguish their group members?A.By using a special whistle. | B.By using special gestures. |
C.By speaking special languages. | D.By different means of swimming in the sea. |
A.They can answer while being called. |
B.They can express their feelings with words. |
C.They can perform different whistles. |
D.They can live individually or in groups. |
A.See each other clearly. |
B.Use the smell underwater. |
C.Have nests and get back regularly. |
D.Call each other by name and make response. |
A.Protecting natural environment. |
B.The scientific discoveries. |
C.The development of scientific technology. |
D.The harmonious relationship between man and animals. |
【推荐3】What are dreams for? A handful of theories have the most influence. Sigmund Freud famously claimed that they reveal hidden truths and wishes. Despite being largely unsupported by evidence,researchers found that students in the U.S.,South Korea,and India were much more likely to accept the view. In the same study,respondents said that dreaming about a plane crash would cause them more anxiety than an official warning about a terrorist attack. More recent research suggests that they may help us process intense emotions,or perhaps sort through and strengthen memories,or rehearse responses to threatening situations.
Even if dreams can’t foretell the future,they seem to expose our shared fascinations. The majority of dreams occur during REM sleep cycles,of which the average person has four or five a night. A study of Canadian university students found the most common dream topics to be school,falling,being chased,and arriving too late for something.
For all the commonalities dreams exhibit,they vary across time people who grew up watching black-and-white TV are more likely to dream in black and white—and culture. A 1958 study determined that compared with Japanese people,Americans dreamed more about being locked up,losing a loved one,finding money. Japanese people were more likely to dream about school,trying repeatedly to do something,being paralyzed with fear,or “wild,violent beasts.”
If human dreams sound boring,bear in mind that even negative ones can have positive effects. In a study of students taking a French medical—school entrance exam,60 percent of the dreams they had beforehand involved a problem with the exam,such as being late or leaving an answer blank. But those who reported dreams about the exam,even bad ones,did better on it than those who didn’t.
1. What do you know about Freud’s view on dreaming?A.It will cause people more anxiety. |
B.It is already been proved by evidence. |
C.It is popular with some American and Asian students. |
D.It can reveal the hidden truth and predict the future. |
A.make emotions intense | B.help prepare for special situations |
C.reduce our memories | D.help us take notes |
A.The average person has four or five sleep cycles a night. |
B.Canadian students aren’t worried about being late for schoo1. |
C.Americans usually share the same dream topics with Japanese. |
D.Films about wild beasts may be widely shown in America in 1958. |
A.your dream will come true |
B.you will be depressed with fear |
C.you are supposed to take it seriously |
D.it shows that you care a lot about the exam |
【推荐1】Some places in the world have strange laws. It's important for you to know about them before going there.
Whoever likes to chew gum (口香糖) may have to leave Singapore. The government really wants to keep the city clean and will fine you for chewing gum.
Before you leave for the United Arab Emirates, you'd better make sure you aren’t visiting during Ramadan (斋月). During that time you aren’t allowed to eat or drink in public. Tourists have been fined up to $275 for drinking in public.
In Thailand it's against the law to drive a car or motorcycle without a shirt on, no matter how hot it is. Punishments are different in different areas and can include warnings and tickets costing about $10. No joke--the local police will stop you.
Studies in Denmark have shown that cars with their headlights on are more noticeable by other drivers than those with their headlights off. Drivers there are required to leave their headlights on even during the day, or they may face a fine up to $100.
Make sure you know about these laws before your next trip. Better safe than sorry.
1. What is mainly talked about in the text?A.How to make your trip around the world safe. |
B.Why there are strange laws in the world. |
C.Interesting places you can go to around the world. |
D.Some strange laws you should know about for your trip. |
A.you should wear your shirt even though it's hot |
B.the police will play a joke on you |
C.the police will give you tickets costing about $10 |
D.you should always keep your headlights on |
A.In Thailand it's against the law to drive a car or motorcycle with a shirt on. |
B.The Singaporean government cares a lot about its environment. |
C.Tourists in the United Arab Emirates shouldn't eat in public. |
D.You can turn your headlights off in daytime in Denmark. |
【推荐2】While physical bookshops had to close their doors during the lockdowns, sales rose strongly.
Barbara White is the buyer and children’s book manager at Wimbledon Books, an independent store in southwest London. “Obviously we had to close, but we did click-and-collect, which, in the run-up to the 2020 Christmas, was crazily busy,” she says. “People were rediscovering books and wanting to be supportive.”
After the Christmas period, sales did begin to falter, but Ms. White says a website called Bookshop.org appeared. An online retailer (零售商) of new books that first started in the US in January 2020, it shares its profits (利润) with independent physical bookstores.
Customers order from Bookshop.org, and the books are sent out from a wholesaler. Independent shops registered with (在……登记) Bookshop.org are not involved in this process; however they still get to share about a third of its profits every six months.
In addition, independent stores get all the profits from the sale of books on Bookshop. org from orders that originate through links (链接) from their own websites, social media posts, or email newsletters.
“Our goal is to help independent bookshops get a bigger share of online sales,”says Nicole Vanderbilt, managing director of Bookshop.org’s UK arm.
However, some people are arguing that it would still be better if customers buy direct from an independent bookstore.
One author who is focused on independent shops is Robin Ince, who is also a comedian, actor, and co-presenter of BBC podcast The Infinite Monkey Cage. He has just published his latest book,The Importance Of Being Interested, and is now on a tour of more than 100 such UK bookshops to sell the book.
He says that while many bookshops suffer heavy losses because of COVID-19, they still show their true worth.“Independent bookshops have kept going, and their relationship with their customers has improved,” he says.“Some got on their bikes and sent their books to people’ s front doors.” Mr Ince hopes that independent physical bookstores are here to stay despite (尽管) the advantages of buying online.
1. What kept Wimbledon Books busy before the 2020 Christmas?A.The rising sales of books. |
B.The new books from Bookshop.org. |
C.Preparing gifts for readers. |
D.Rediscovering wonderful books for readers. |
A.Quicken. | B.Double. | C.Drop. | D.. Remain. |
A.They must be American bookstores. |
B.They must draw in new customers continuously. |
C.They can get all the profits related to themselves. |
D.They should pay the online retailer one third of their income. |
A.They will disappear soon. |
B.They have upgraded their services. |
C.They need to change their sales model. |
D.They have improved their shopping environment. |
【推荐3】Many Americans sleep in a room that’s stopped occasionally with some form of artificial light — whether it’s coming from a TV, a jumble of electronics or a streetlight. New research suggests that one night of sleep with just a moderate amount of light may have negative effects on health.
Dr. Phyllis Zee, senior author of the new study and director of the Center for Circadian and Sleep Medicine at Northwestern University, conducted an experiment so far, which indicates being exposed to light at night may be adverse in a variety of ways and could lead people to chronic diseases. For the study, all the participants spent their first night sleeping in a dark room. The next night, half of them slept in a lighted room. Meanwhile, the researchers ran tests on the sleepers: they recorded their brainwaves, measured their heart rates and drew their blood every few hours, among other things.
The results show several clear differences between the two groups. Unlike those who spent both nights in the dark, the group exposed to the light had increased heart rates throughout the night.
The study’s findings that metabolic (代谢的) health suffered aren’t entirely surprising. “This is enough to suggest that if people sleep under light, even a little light, it may pose a threat to their health, particularly cardiovascular (心血管的) health, and increase the risk of disease.” says Dr. Charles Czeisler, chief of the Division of Sleep and Circadian Disorders at the Brigham and Women’s Hospital in Boston and a professor at Harvard Medical School.
In fact, the report did not control for the effects of sleep duration and other potential factors. It’s worth noting that researchers still had a indistinct definition of whether light can affect insulin (胰岛素) changes in the body, but it’s safe to say that even a little light can be bad for your health.
1. What does the underlined word “adverse” mean in paragraph 2?A.Stressful. | B.Harmful. | C.Different. | D.Disordered. |
A.By comparing test data. | B.By monitoring light sources. |
C.By analyzing sleeping patterns. | D.By recording emotional changes. |
A.The value of the experiment. | B.The prospect of the experiment. |
C.The limitation of the experiment. | D.The application of the experiment. |
A.Sleeping with the Lights on: Is it ever OK? | B.Light Theropy Improve Sleeping: Have a try? |
C.How does a Lighter Sleeper Get More Rest? | D.Does Bedroom Lighting Improve Sleep Quality? |
【推荐1】Most of us relate creativity to our concept of self, Either we’re “creative” or we aren’t, without much of a middle ground. “I’m just not a creative person!” a frustrated student might say in art class, while another might blame her talent at painting for her difficulties in math, giving a comment such as, “I’m very right-brained.”
Dr. Pillay, a tech entrepreneur and an assistant professor at Harvard University, has been challenging these ideas. He believes that the key to unlocking your creative potential is to ignore the traditional advice that urges you to “believe in yourself. “ In fact, you should do the opposite: Believe you are someone else.
Dr. Pillay points to a 2016 study examining the impact of stereotypes (固有印象) on one’s behavior; The authors, educational psychologists Denis Dumas and Kevin Dunbar, divided their college student subjects into three groups, instructing the members of one to think of themselves as “romantic poets” and the members of another to imagine they were “serious librarians” (the third group was the control). The researchers then presented all the participants with ten ordinary objects, including a fork, a carrot, and a pair of pants, and asked them to come up with as many different uses as possible for each one. Those who were asked to imagine themselves as romantic poets came up with the widest range of ideas, whereas those in the serious-librarian group had the fewest. Meanwhile, the researchers found only small differences in students’ creativity levels across academic majors.
These results suggest that creativity is not a fixed individual characteristic but a “malleable product, as long as he or she feels like a creative person. Dr. Pillay argues that, besides identifying yourself as creative, taking the bold, creative step of imagining you are somebody else is even more powerful. So, wish you were more creative? Just pretend!
1. According to the passage, who is more likely to unlock his creative potential?A.An art major who always believes in himself. |
B.A math major who has excellent academic performance. |
C.A physics major who likes to imagine himself as a poet. |
D.A history major who works as a librarian on weekends. |
A.The creativity of the college students. |
B.The stereotypes of the college students. |
C.The impact of stereotypes on one’s behavior. |
D.The influence of creativity on one’s behavior. |
A.Settled. | B.Continuous. | C.Predicable. | D.Changeable. |
A.there is no doubt that we are either creative or not. |
B.a student who doesn’t do well in art class is not creative. |
C.right brain determines whether a person is creative or not. |
D.if we pretend to be creative, then we might be really creative. |
![](https://img.xkw.com/dksih/QBM/2021/4/23/2706062294392832/2706715737161728/STEM/d01495761fa541bfa09aa5dac1628e8e.png?resizew=530)
1. According to the job advert, the website is looking for a person __________.
A.who has high calibre(能力) |
B.who gets careers advice for young people |
C.who allows university graduates to find jobs |
D.who will be in charge of web pages for graduates’ CVs |
A.Common types of software. |
B.Phone number, address, e-mail. |
C.Some websites. |
D.Some kinds of languages. |
A.Attractive salary. |
B.Ordinary conditions. |
C.High pay and good conditions. |
D.Attractive salary and health benefit. |
A.Iwanttobe.com.cn/ before 21 March. |
B.Iwanttobe.com.cn/ on 21 March. |
C.Jobs@iwanttobe.com.cn/ on 21 March. |
D.Jobs@iwanttobe.com.cn/ before 21 March. |
A.young people to get career advice |
B.university graduates finding jobs |
C.young people to find friends |
D.employers finding candidates |
【推荐3】University of Pennsylvania researchers say that for the first time they have linked social media use to increases in depression and loneliness. The idea that social media is anything but social when it comes to mental health has been talked about for years, but not many studies have managed to actually link the two. To do that, Penn researchers, led by psychologist Melissa Hunt, designed a study that focused on WeChat, Snapchat and Instagram.
The study was conducted with 143 participants, who before they began, completed a mood survey and sent along photos of their battery screens, showing how often they were using their phones to access social media. “we set out to do a study which attempts to imitate real life.” Hunt said.
The study divided the participants into two groups: The first group was allowed to maintain their normal social media habits. The other, the control group, was restricted to 10 minutes per day on social media. The restrictions were put in place for three weeks and then tested for now comes such as fear of missing out, anxiety, depression and loneliness.
The results showed a very clear link between social media use and increased levels of depression and loneliness.” Using less social media then you normally do would lead to significant decreases in both depression and loneliness,” Hunt said.
Social media invites what Hunt calls “downward social comparison.” “When you’re online, it can sometimes seem that everyone else is cooler and having more fun and included in more things and you’re left out,” Hunt said. And that’s just generally discouraging. “Every minute you spend online is a minute you are not doing your work or not meeting a friend for dinner or having a deep conversation with your roommate.” And these real life activities are the ones that you can encourage self-esteem and self-worth, Hunt added.
“People are on their devices, and that’s not going to change,” she said. But as in life, a bit of control goes a long way.
1. What can we learn from the first paragraph?A.Social media is a good tool for social activity. |
B.Social media can’t increase people’s social activities. |
C.Social media is the cause of depression and loneliness. |
D.No studies about social media and mental health have been done. |
A.To participate in a mood survey first. |
B.To show how often they use their phones. |
C.To keep their normal social media habits. |
D.To stay in the lab for three weeks. |
A.Social comparison makes people work harder. |
B.Social media activities can increase self-esteem and self-worth. |
C.People will reduce the use of social media. |
D.controlling the use of social media will make a difference to people’s life. |
A.The tendency of using social media. |
B.The importance of the study on social media. |
C.The disadvantage of using social media. |
D.A study on the relationship between social media and mental health. |
【推荐1】A new study, a project of the researchers from the University of Pittsburgh in Pennsylvania, finds that a fitness tracker (健康追踪器) probably does not help with weight loss.
The trackers are designed to record your physical activity. They are usually worn around the wrist (手腕), where they record a person's heart rate. The research team looked at two groups of people. The first wore a fitness tracker and took part in health consultation with experts for best weight loss plan. The researchers compared this group with people who only got health consultation.
The study found that those only speaking with the health experts lost nearly 6 kilograms, but those using a fitness tracker lost only 3.5 kilograms. John Jakicic the lead researcher, questioned the use of these trackers for weight loss.
The study involved 470 people age between 18 and 35. Some of them were overweight, while others were considered obese. Over three fourths of them were women. All were told to increase physical activity and start on a low-calorie diet. They had their weight measured once every six months. After six months, researchers divided the group into two parts: one continued with monthly consulting, while members of the other group were given a fitness tracker. Eighteen months later, both groups showed great improvements in fitness, physical activity and diet, with no big difference between groups. However, when it came to losing weight, the people who only spoke with experts lost nearly twice as much weight.
Jakicic said, “The study's findings are important because effective long-term treatments are needed to deal with America's obesity.”More information is needed, he added, to learn how to best use these trackers to help adults who want to lose weight.
1. Both groups of people in the study were asked to .A.start on a high-calorie diet. | B.wear a fitness tracker |
C.consult experts | D.record their heart rates |
A.Wearing fitness trackers hardly helps people lose weight. |
B.Physical activity and diet have no effect on weight loss. |
C.Dealing with obesity needs effective long-term treatments. |
D.There are great differences in health between both groups. |
A.The study went on for about two years. |
B.More than 120 men took part in the study. |
C.Health consulting helps lose almost 6 kilograms. |
D.Wearing a fitness tracker is useful for keeping slim. |
A.describe how the researchers carried out the study |
B.show regular consulting for weight control is necessary |
C.persuade readers to wear fitness trackers for weight control |
D.warn women are more likely to suffer from weight problems |
My family had dreamed of a trip to London for a long time. Luckily it was possible for us to realize our dream because all of us were free on the weekend.
We planned to drive into Cambridge and caught the 7: 34 train to Liverpool Street Station.Then my wife and I would separate from Joan, my wife’s sister, to do different things and finally meet again for lunch. And after lunch, we would go to the concert.
But we were late because of a thick London fog. The train had to move along so slowly that it was not until 10:30 that it got there. In spite of our late arrival, Joan decided that she would go to see the Crown Jewels in the Tower of London while we went shopping. It was only after her sister had disappeared into the fog that my wife realized that we hadn’t decided where we should meet for lunch. Since I had our three tickets for the concert in my pocket, this was indeed a problem. We didn’t have any mobile phones at that time. There seemed to be nothing we could do except taking a taxi to the Tower of London, and try to find her there. Needless to say, we didn’t find her.
It was now one o'clock, and the concert began at 2: 30. “Perhaps she will think of waiting outside the concert hall,” said my wife hopefully. By this time the fog was so thick that road traffic had to stop, and the only way to get there was by subway. Hand in hand we felt our way along the road to where we thought the nearest station should be. An hour later we were still trying to find it.Just when I was about to become angry, we met a blind man tapping his way confidently through the fog. With his help we found the subway station which was just fifty meters down the road.
By now it was far too late to get to the concert hall before the performance began at 2: 30, so we decided to return to Cambridge. It took seven hours instead of the usual two to make that journey. Nor were we able to get any food and drink on the train. We were tired and hungry.
We finally reached home at ten. Opening the door we were amazed to find Joan at home; she had seen the Crown Jewels, had managed to get another ticket for concert, and had had a wonderful dinner at a restaurant. Of course, she managed to get home, too. Oh my god!
1. What did the writer plan to do after lunch that day?
A.Go to the concert. | B.Return to Cambridge. |
C.Go shopping. | D.See the Crown Jewels. |
A.they were late for the concert |
B.Joan didn’t want to go to the concert |
C.there was a thick fog |
D.they planned to do different things until lunch time |
A.A taxi driver. | B.A blind man. |
C.His wife. | D.Joan. |
A.quite interested | B.rather disappointed |
C.tired and hungry | D.very enjoyable |
I had read American Pastoral three times and I was filled with so much respect and fear towards the book that it frightened me when it came to my own writing. Then one day it hit me that it wasn’t the first thing he’d written, so I picked up Goodbye, Columbus. It’s amazing to think of Roth, published at 26, and to see how much he grew by the time he wrote American Pastoral. The fact that you could have people just be extremely excited was a really calming, influential thing for me. It made me want to write.
Are You There God? It’s Me, Margaret by Judy Blume
I connected so much with that character as a young girl. As I got older, I realized that the settings of books that I love most are always the spiritual description. I still come back to this book all the time because of the vulnerability(脆弱性) in there. Every time I write now I think about that feeling that you get from some books, that you’ve really been let into the most frightened and quiet corners of someone’s soul.
The Silence of the Lambs by Thomas Harris
I remember reading The Silence of the Lambs. There’s nothing more terrifying than someone who is intelligent and dangerous. He even had that longing to eat humans, which was terrible, but the magic was that he’d then say these really insightful things. I wouldn’t have written anything if I hadn’t read the line, “We strongly want to have what we see every day,” in my head. I loved the frightening insights into the possibilities of what’s existing unseen around you.
1. Why did the author decide to read Goodbye, Columbus?A.It taught him how to write. | B.The book is highly spoken of. |
C.He was touched by Roth’s books. | D.He was full of admiration for the author. |
A.The setting of the book. | B.The description of spirit. |
C.The weakness of people. | D.The background knowledge. |
A.A fairy tale. | B.A love story. | C.A science fiction. | D.A horror story. |