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[阅读小分队] 【Native Speaker每日训练计划—89系列】【89-12】科技

发表于 2017-6-12 17:47:18 | 显示全部楼层 |阅读模式
内容: Jenny Chen   编辑: Cecile Zhang

Wechat ID: NativeStudy  丨  Weibo:

Part I: Speaker

Bacterially Boosted Mosquitoes Could Vex Viruses
By Karen Hopkin on June 8, 2017

It may sound strange, but scientists are celebrating the survival and spread of tens of thousands of mosquitoes they released in Northeastern Australia. The whole thing makes more sense when you know that these mosquitoes are not just any run-of-the-mill bloodsuckers. They’re weaponized—infected with a type of bacteria that prevents the spread of Zika, dengue and other mosquito-borne viruses.

The bacterium, called Wolbachia, is present naturally in nearly two-thirds of all insect species, although it’s not usually found in Aedes aegypti, the mosquito responsible for spreading Zika, dengue, yellow fever and chikungunya.

But when researchers introduced Wolbachia into mosquitoes in the lab a decade ago, the bacteria bollixed the skeeters, making them unable to transmit their viruses to humans. Which gives public health experts hope that by releasing big groups of Wolbachia-infected mosquitoes into problem areas, they’ll spread Wolbachia to the local populations—making them incapable of transmitting viral diseases to people.  

But a big question was, will the weaponized mosquitoes remain contained where they’re let loose, or will they move enough to mingle with their wild brethren?

So researchers in Australia ran a test. In 2013, they released some 35,000 Wolbachia-carrying Aedes aegypti at one site, 131,000 at a second site, and 286,000 at a third site, all in the city of Cairns. And they tracked the insects’ dispersal. Seems the souped-up skeeters spread outward from the two larger introduction areas at a slow but steady rate of about 100 to 200 meters per year. The mosquitoes in the smaller group stayed put. The study is in the journal PLoS Biology. [Tom L. Schmidt et al., Local introduction and heterogeneous spatial spread of dengue-suppressing Wolbachia through an urban population of Aedes aegypti]

The results indicate that Wolbachia-infected mosquitoes could be effective against viral diseases, if—like bug spray—they’re applied liberally over larger areas. In the public health community, that finding may cause a real buzz.

—Karen Hopkin
[Rephrase 1, 02’08]

Source: Scientific American

Part II: Speed

How to tell whether that whiskey is fake
By Ryan Cross 丨  June 8, 2017

[Time 2]
As whiskey takes off in popularity around the globe, con artists aren’t far behind. Because their “sham drams”—cheap, blended whiskeys masquerading as expensive single-malt scotches—are hard to ID without a master distiller, teams of chemists have designed all sorts of methods for picking out the fakes. But they require deep knowledge of the liquor’s complex chemical constituents, something your average barfly isn’t likely to have. So a group of German researchers came up with a simpler approach: using fluorescent dyes to compare different drinks. The dyes, which are synthetically produced, give off different colors depending on the molecular makeup of the brew. Comparing 33 different whiskeys in a head-to-head competition, the team was able to classify the fluorescent signals into groups based on country of origin, blending status (single malt or blended), age, and taste (rich or light), the team writes today in Chem. The sensor can’t definitively identify a whiskey, but it can be used to compare a questionable sample to a known one. The same scientists have also used the fluorescent dyes to differentiate between white wines, fruit juices, drugs, and proteins, and they suggest such sensors could be used in the future to weed out counterfeits and impurities in foods, drinks, drugs, and perfumes.
[209 words]

Source: Science

Are you lying about your identity? Artificial intelligence can tell by how you use your mouse
Matthew Hutson  丨  June  9, 2017

[Time 3]
Every year, millions of people have their identities stolen. There’s no foolproof way to pinpoint fakers, but thanks to Italian researchers, investigators may soon have another tool at their disposal—a way to suss out frauds and other liars online with just a few clicks of a mouse.

Traditional methods of lie detection include face-to-face interviews and polygraphs that measure heart rate and skin conductance. But they can’t be done remotely, or with large numbers of people. Researchers have come up with effective computer-based tests that measure reaction time in response to true and false personal information. For the tests to work, though, experimenters have to know the truth in advance.

To get around this obstacle, a team of Italian researchers has come up with an innovative way of figuring out the truth. They asked 20 volunteers to memorize the details of a fake identity and assume it as their own. The subjects then answered a set of yes-or-no questions using a computer, as did 20 truth-telling volunteers. Questions included things like: “Is Giulia your name?” and “Were you born in 1995?” Researchers recorded each answer and measured how the subjects’ mouse cursors moved, from the bottom middle of the screen to “yes” and “no” buttons in the top two corners.

Because liars can get to be as good as the rest of us at telling the truth, the researchers threw a wrench into their experiment. In addition to the 12 expected questions, they asked 12 unexpected questions based on the volunteers’ new identities. For example, they asked about a person’s zodiac sign, based on their birth date. And they asked about the capital city of the subject’s presumed region. A fraud might have memorized a fake birthday, but not known the corresponding zodiac sign, or been able to calculate it quickly enough. “We’ve found that if people rehearse lies, lying can be as easy as telling the truth,” says Bruno Verschuere, a forensic psychologist at the University of Amsterdam who was not involved in the research, “except when you ask unexpected questions.”
[343 words]

[Time 4]
The experimenters trained a computer to sort liars from truth tellers using the number of incorrect answers they gave. The team’s four machine-learning algorithms ranged in accuracy from 77.5% to 85%. But when the researchers included features of the mouse paths—such as deviation from a straight line—in their training materials, computers were able to successfully pick out the liars 90% to 95% of the time, the researchers reported last month in PLOS ONE.

They also trained and tested the algorithms using only questions that the liars answered truthfully, such as whether they were Italian. The algorithms could still identify the fibbers with 77.5% to 80% accuracy. Jumping back and forth between telling the truth and lying seems to have a broad effect on people’s behavior, the scientists say. Having to tell a lie changes the way people tell the truth.

But would such a method work in the real world? Giuseppe Sartori, a forensic neuroscientist at the University of Padua in Italy and an author of the paper, says it could be used as a “first screen” to check people’s alibis in criminal investigations, verify identities online, or even cull terrorists from refugees at border checkpoints. It likely won’t have the same accuracy it does in the lab, but he calls the study a good “proof of concept.”

“It’s a clever idea,” says Giorgio Ganis, a cognitive neuroscientist at Plymouth University in the United Kingdom. “But it’s not obvious that it’s going to be super useful.” Ganis notes that in the real world, fraudsters would likely spend more time researching their backstories, making surprising questions harder to find. “You’re going to catch the dumb criminals and dumb terrorists,” he says, “which is better than nothing, I guess.” Sartori adds that even though impostors might learn their purported zodiac sign, other unexpected questions are practically unlimited. Do they know the cross streets of their purported home address? Do they know the layout of the restaurant where they say they were on the night of a crime? The study brings a whole new meaning to the game of cat and mouse.

Source: Science

New clues to why a French drug trial went horribly wrong
Hinnerk Feldwisch-Drentrup  丨  June 8, 2017

[Time 5]
Scientists are one step closer to understanding how a clinical trial in France killed one volunteer and led to the hospitalization of five others in January 2016. A new study shows that the compound tested in the study, BIA 10-2474, has effects on many other enzymes in addition to the one it was supposed to inhibit. These “off-target” effects might explain why the drug caused side effects ranging from headaches to irreversible brain damage.

“We suspected that BIA 10-2474 was a bad compound—now we know for sure,” says neuropharmacologist Daniele Piomelli from the University of California, Irvine, who was not involved in the new study.

The molecule was produced by Portuguese drugmaker Bial and tested in healthy human volunteers in a phase I study by the French contract research company Biotrial in Rennes. BIA 10-2474 inhibits an enzyme called fatty acid amide hydrolase (FAAH), which breaks down endocannabinoids in the brain. Previous research had suggested that FAAH inhibitors might help treat anxiety, chronic pain, or neurodegenerative disorders such as Parkinson’s disease. Although other drug developers, including Pfizer, had already dropped FAAH inhibitors because of disappointing efficacy studies, most of the molecules were shown to be safe, as the U.S. Food and Drug Administration confirmed in August 2016.

But that was not true for BIA 10-2474. Neuroscientist Steven Kushner of Erasmus University Medical Center in Rotterdam, the Netherlands, together with chemical biologist Mario van der Stelt from nearby Leiden University and colleagues at several other institutes, set out to find out why.

The researchers used a technique called activity-based protein profiling, which allowed them to screen the molecule’s activity against a very large group of enzymes in living human cells. They found that at higher concentrations, the Bial drug disrupted the activity of several lipases, enzymes that break down fatty acids; the Pfizer drug, by contrast, did not. One of the off-target enzymes is called PNPLA6; previous studies have linked defects in the gene encoding for PNPLA6 to rare neurological disorders. The results suggest that BIA 10-2474 may disrupt how neurons in the cerebral cortex metabolize lipids, the team reports today in Science.
[354 words]

[Time 6]
The researchers can’t be sure that the off-target effects actually caused the brain damage seen in the volunteers, however. “We do not have evidence for a causal relationship yet,” Van der Stelt says. One way to find out might be to analyze samples of the deceased volunteer’s brain.

The off-target effects can be species-dependent, says Van der Stelt, which could explain why studies in rats and mice did not identify the drug’s danger. But Bial could have known about the risk if it had thoroughly screened for off-target effects in human cells, like the new study does, Van der Stelt says; that’s what Pfizer did with its FAAH inhibitor. “If Bial had done the same, they might have reached a different conclusion,” Van der Stelt says.  

Jürg Gertsch, a biochemist at the University of Bern, agrees; he says it’s “unbelievable” that Bial did not do a more extensive study of the drug’s effects before giving it to humans. Gertsch has himself investigated the effects of BIA 10-2474 in human blood cells; that study has yet to be published.

“The new study does not provide an explanation for the toxicity observed with the compound BIA 10-2474, but does highlight its promiscuous nature,” says Pomelli, who calls the decision to move forward with the human trial “deeply misguided.” He says the doses given to the volunteers in the group where the accident occurred were also unnecessarily high, as full inhibition of FAAH occurred at a much lower level.

Bial welcomes “any study” that could help shed light on the incident, a spokesperson says. They add that results from the company’s own investigation largely align with the new paper, but that in Bial’s opinion, they are unlikely to explain the neurological effects seen in the study.

Although Bial and Biotrial have been heavily criticized for the study, French authorities have concluded that the companies did not violate clinical trial regulations. In the wake of the case, the European Medicines Agency is developing stricter rules for “first-in-human” studies.
[336 words]

Source: Science

Part III: Obstacle

New football helmets could limit brain injuries
Lillian Steenblik Hwang   |   May 24, 2017

[Paraphrase 7]
Two football players collide on the field. Both are wearing helmets. Still, their heads bang together, risking serious injury. A new helmet design might offer these players’ brains much better protection. Key to its advantage: three layers of energy-absorbing insulation. Most helmets today offer just a single layer.
“Current helmets do a good job of reducing the force that gets to the skull,” says Ellen Arruda. She’s a mechanical engineer at the University of Michigan in Ann Arbor. But reducing force isn’t the only problem. A blow to the head sends waves of kinetic energy through the skull and into the brain. Kinetic energy is the energy of motion.

“Let’s imagine you have an egg and you hit the egg,” explains Michael Thouless, also a mechanical engineer at Michigan. Hitting the egg could crack its shell. But the impulse of kinetic energy might also send the egg flying.

Something similar happens when an athlete’s head gets hit. Even if the skull doesn’t crack, an impulse of energy travels through the skull and brain. But the brain and skull don’t always move at the same speed. So parts of the brain can crash against the inside of the skull.

Bike helmets are made to crush, or deform, on impact. That action absorbs a good deal of the kinetic energy. Afterward, however, the helmet must be thrown out. That’s not practical for football and other contact sports. And helmets for those sports do a poor job of cutting down on that kinetic energy, says Arruda.

Ellen Arruda shows the three-layer design that her team at the University of Michigan developed to better cushion the head during collisions on the field.

Evan Dougherty/Michigan Engineering

Now the two Michigan engineers have worked with graduate student Tanaz Rahimzadeh to improve the standard helmet. Their new design uses three layers of polymers, plastic materials whose molecules are chains of repeating groups of atoms. Together the three layers reduce both the force of an impact and the kinetic energy of the impulse.

Different layers, different functions
The team tackled the project in response to Head Health Challenge III. This competition is part of a four-year program sponsored by the National Football League (NFL), the National Institute of Standards and Technology and others. The overall goal of the program is to provide better protection from brain injuries.

The Michigan team focused first on the head, which is where the damage occurs. “We analyzed what causes the brain to move relative to the skull when you hit the skull,” Arruda explains. Understanding the movement and the factors that cause it led her team to its three-layered design.

Next the team picked out polymers. “We knew what properties we were looking for,” says Thouless. With that knowledge, the team looked through catalogs for materials to find “a combination that seemed to work.”

To sop up kinetic energy, the team chose a viscous  elastomer for the innermost layer. Like elastic, this material bounces back to its original shape after something deforms it. Unlike regular elastic, however, the material returns to that shape slowly. The memory foam in some mattresses and pillows is an example of this type of material.

As the material changes form and recovers, it sheds some of its kinetic energy. This means that in a helmet, less of that energy would get through to the head. How much less depends on the specific type of polymer. It also depends on the frequency, or wavelength, of the impulse. For any particular viscous elastomer, there’s one frequency of energy that it sheds best.

However, a single impact doesn’t send an impulse with just one frequency, notes Thouless. Instead, the impulse spreads across the helmet and into the head at a range of frequencies. It’s kind of like hitting a bunch of piano keys with your fist. You’d hear a bunch of clashing notes with different frequencies.

That’s where the other two layers of the design come in. As in standard helmets, the outer two layers absorb a good deal of the force of an impact. Basically, they soften the blow.

Those layers also work together to change the group of frequencies from an impact into just one frequency. It’s a bit like an orchestra tuning up to match a single note. The frequencies bounce between those two layers. When the energy finally passes through, it’s tuned to the one frequency that works best with the innermost layer, explains Christian Franck. He’s an engineer at Brown University in Providence, R.I., who did not work on the project.

More than football players may benefit
The group’s prototype worked well. Compared to other helmets, only one-fifth of the kinetic energy from an impact made it through to the head. The team described its results in the December 2015 issue of the Journal of the Mechanics and Physics of Solids.

The design is now one of five finalists in the Head Health Challenge competition. Over the next year, the team will do more work to further improve its design. For instance, the group plans to experiment with other polymers.

Franck describes the new helmet as “a very clever design.” He also has studied how energy from an impact affects the brain. “I like the idea of reducing energy from the impact before it hits the brain,” he says. “I absolutely believe that’s the right approach.”

“This helmet doesn’t have to cost anything more than an existing helmet,” says Arruda. That means athletes at any age could benefit if they play any contact sport, such as rugby or soccer.

“The same design can be used in other applications,” she adds. For example, multiple layers could help improve the shoulder and knee pads used in some sports. The layered approach also might help make playground surfaces safer.

Ideally, the new approach will lead to fewer concussions, a type of traumatic brain injury. “The brain is a very delicate structure, and it should be protected at all costs,” says Franck.
[997 words]

Source: Science News for Students


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发表于 2017-6-13 21:19:25 | 显示全部楼层
sensor n. 传感器,感应器;感测器

>>How to tell whether that whiskey is fake
S2 2min53s    [209 words] --- 73 wpm
intent: how to identify the fake whiskey
craft: problem-solution- further application

>>Are you lying about your identity? Artificial intelligence can tell by how you use your mouse
S3 3min57s    [343 words] --- 86 wpm
S4 3min48s    [352 words] --- 92 wpm
intent: how to identify the liars who use a fake ID card.
craft: problem: It’s hard to identify the liar who has a fake ID card - traditional solution and its shortcoming - new solution with a weakness- improve the new solution- this issue of practical application: Although whether the new way is useful is unknown, it is better than nothing.

>>New clues to why a French drug trial went horribly wrong
S5 4min32s    [354 words] --- 78 wpm
S6 3min32s    [336 words] — 95 wpm
intent:  a horrible clinical trial
craft: case - nature: drugs might has side effects and some side effects might lead to unexpected damage - describe the horrible clinical trial and make comments on it. (中部看不明白,明重看)
发表于 2017-6-13 23:23:13 | 显示全部楼层
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