题目内容
（请给出正确答案）
When the cell has excess energy, it stores this energy by forming ______.
A．phosphate
B．ADP
C．AMP
D．ATP
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cancer. originally,because of a lawsuit that alleged such a link Network news programs ran their own tests of cell phones,reporting to the public that some cell phones exceed the maximum level of emitted radio frequency energy allowed by the US Federal Communications Commission.
In 2000.it was estimated that there were 92 million cell phone users in the United States and this number was growing by 1 million every month. More recently,the Cellar Telecommunications & Internet Association estimated that there were almost 170 million US cell phone users, and the seriousness of brain tumours, this is clearly a topic of wide concern.This report summarizes what we now know about the carcinogenicity of using cell phones.
Cell phones operate with radio frequencies.a form. of energy located on the electromagnetic spectrum between F M radio waves and the waves used in microwave ovens,radar;and satellite stations.Cell phones do not emit ionizing radiation,the type that damages DNA and is known to have the ability to cause cancer.
Cell phone technology works on a system of geographically separated zones called "cells" Each cell has its own "base station" that both receives and emits radio waves.When a call is placed from a cell phone,a signal is sent from the cell phone antenna to that cell's base station antenna.The base station responds to the cell phone signal by assigning the phone an available RF channel.When the RF channel is assigned,radio signals are simultaneously received and transmitted, allowing voice information to be carried between the cell phone and the base.The base station transfers the call to a switching centre.where the call can be transferred to a local telephone carrier or another cell phone.
6.There has existed argument about the link between cell phone and brain tumour.()
7.The rapid growing number of cell phone users has been a great concern in the US.()
8.The 3rd paragraph tries to prove that cell phones do not cause brain cancer.()
9.A switching centre is needed when we make a call through cell phone.()
10.The topic of the passage is about cell phone and cancer.()
Meanwhile, in a larger chamber down the hall, Glass is monitoring tropical monkeys. He has found that exercise and arousal from sleep have major impacts on the biological rhythms of the monkeys, permanently shifting their clocks in the absence of normal daylight and darkness cues.
Glass's research and that of others could have implications for the millions of people who take com monanti-depressants and other drugs that affect serotonin in the brain. It has long been known that the substance is a key player in the biological clock, and that the region has an unusually high concentration of receptors for the neurotransmitter.
Glass's work is part of the fast-growing field of circadian(or daily)rhythm research focused on a region at the base of the brain, the size of a corn kernel, that scientists discovered 25 years ago is the body's timing mechanism.
Like other animals and even plants, humans have built-in clocks that regulate internal functions on a 24-hour basis. For most mammals, the clocks trigger sleep and waking, as well as metabolism, hor mone levels, body temperature and many other changes. This is a particularly exciting time for circadian-rhythm researchers. In recent times, scientists at universities in Illinois, Texas and Japan have found genes involved with the clock, including one that appears to be a basic building block of the mechanism and is common across all species, from fruit flies to humans. Meanwhile, researchers like Glass, whose work has attracted US $1.2 million(9.6 mil lion RMB)in grants from the National Institute of Health, are trying to understand how the clock works.
Sitting on top of the optic nerve, the clock is heavily influenced by light. But other factors, too, are involved in resetting the mechanism, most notably physical activity and substances like serotonin. Glass and his students found that, when lights in the hamster chamber were switched off, the serotonin levels in the rodents'clock region shot up: hamsters are nocturnal, meaning they rest during the day and are awake at night. But when hamsters in the midst of their sleep cycle were put onto an activity wheel, a significant rise in serotonin levels was measured in those hamsters that woke up enough to ex ercise.
It has long been known that serotonin is key to body clock function, according to Thomas Wehr, a scientist at the National Institute of Mental Health in Bethesda, Maryland. Researchers at the Mary land Institute took cells from the clock region of the brain, sprinkled serotonin on them and, by monito ring electrical impulses, watched the cells "reset" themselves.
"There are certain drugs used with humans that have also been squirted on these cells in dishes and have been shown to reset the clock in the dish, so it seems quite possible there are similar effects in hu mans who take these drugs. "Wehr says. Indeed, some people taking anti-depressants do report sleep disorders such as insomnia or daytime drowsiness that could be related to changes in their biological clocks. Human studies have yet to focus on the issue.
Studies have found that serotonin affects the clock in different ways, depending on the point in the cell's daily cycle that it is administered. Glass rece
A．Y
B．N
C．NG
W: For me, well, I was thinking the cell phone is the most wonderful thing.
M: Really？
W: Yeah, (19) I even couldn't live without mine. It's so convenient! I can call my friends anytime and they can always call me. Or if I'm in trouble I can call for help...
M: You mean like calling your parents？
W: Yeah, like parents, and if I'm running late, I'm able to call a friend if I'm, like, on the bus or something.
M: (20) But the problem with cell phones is that people use them too much for every little thing. It's practically glued to their ears.
W: Yeah, and I hate it when people shout into them in a public place and everyone else has to listen to the conversation, especially in restaurants.
M: Well, good manners aren't a wonder of our world! You know, I think the most amazing wonder is e-mail. It has changed the world, and it has totally transformed my business. Everybody at work is always on the computer, responding to e-mails, sending e-mails... That's where most of our business is done now, through e-mail. You are sending reports, getting information. But the bad part is that you are glued to the computer and people expect things to be done right away.
W: Yeah, people are shocked if you go through a day without checking your e-mail. And when you go on vacation and then you come back, maybe there are 200 e-mails waiting for you — all of them urgent.
M: I guess it is like any other tool or device. (21) If it's used correctly, it's very useful.
19．Wily does the woman consider the cell phone one of the wonders of the modem world？
20.What is the problem with cell phones according to the man？
21.How does the man feel about e-mail？
(20)
A．It is used too much.
B．It is more necessary than E-mail.
C．It is very convenient.
D．It has more problems than benefits.
A Cloud of Stem Cell
The pressure on stem cell pioneer Woo Suk Hwang over the way he obtained human eggs for his research is intensifying-particularly in South Korea, where he had been a national hero. In the past week, several new claims have emerged that Hwang may have used eggs that were paid for, as well as eggs from junior members of his laboratory.
Hwang's team, based at South National University, has produced a string of landmark papers in stem cell research, including the first stem cells obtained from a cloned human embryo(胚胎)(W. S. Hwang et al. Science 303, 1669-1674; 2004) and the first patient-matched embryonic stem cells(W. S. Hwang et al. Science 308, 1777-1783; 2005).
For South Korean scientist, cloning pioneer and Snuppy creator, Woo Suk Hwang, things keep going from bad to worse. Last month, he had to admit that as part of the groundbreaking stem cell research he published in 2004, one of his colleagues had paid some women for their egg donations, and that two of the unpaid donors were Hwang's own junior researchers. Amid the moral controversy that followed, Hwang was in hospital for extreme fatigue and exhaustion. He was released earlier this week, only to find one of his former researchers on a national news broadcast claiming that the history-making stem cell lines Hwang created were fake.
The news broadcast was part of a multi-part investigative series by Korea's MBC-TV. Also in the broadcast, the researcher said that Hwang had told him to make up data in order to make it appear as if the South Koreans had created more stem cells, made from patients with diseases, than they actually had. "This is something I shouldn't have done," said the researcher, whose face was not shown on camera and was only identified by his last name, Kim. "I had no choice but to do it."
In a separate interview, Roh Sung Li, the doctor who had provided donated eggs to Hwang's research, said that Hwang had asked Science, the journal that published his paper on patient-specific stem cells, to withdraw the publication. A spokesperson at the journal said that they had not yet received a request to take back, but have e-mailed all 25 co-authors asking for clarification of the allegations(指控). Roh told news media that of the 11 stem cell lines created from patients with diseases, nine were fake. Whether the two remaining lines were valid, and photographed repeatedly to stand in for the other lines, is not clear. Roh also claims that after a visit to Hwang on Thursday, he believes there were no stem cells at all, and that all of the colonies had died in the lab. "I heard some things that I haven't been aware of when I visited Professor Hwang at his request, that there are no embryonic stem cells," he told MBC.
These latest claim comes just 24 hours after a former Hwang cooperator, Dr. Gerald Schatten of the University of Pittsburgh, charged Hwang with fabricating his data. Back in June, the two men had co-authored a paper published in Science that detailed how individual stem cell lines were created for 11 patients through cloning. When Hwang's immoral deeds were uncovered last month, Schatten was already publicly distancing himself from his onetime colleague. But on Tuesday, Schatten, took the next step and asked that his name be removed from the work. His reasons？ "Careful re-evaluations of published figures and tables," he said in his letter, "along with new problematic information, now cast substantial doubts about the paper's accuracy." Hwang has still not responded to these new accusations(指控), and Schatten has declined to comment further.
Hwang's academic affair is the latest plot twist in a drama that's playing out in the Korean press. Several days after Schatten's initial break with Hwang, Seoul's news outlets cited a Korean government official and other sources in both Korea and the U.S., claiming that Schatten had met with
A．Y
B．N
C．NG
Hwang's team has published some milestone papers in stem cell research.
A．Y
B．N
C．NG
A．blood cell
B．lung cell
C．liver cell
D．DNA
The cell (-)SCE || Ag2CrO4(saturated),CrO42-|Ag() is employed for the determination of pCrO42-. Calculate pCrO42-when the cell potential is 0.402 V.
A.CDU-A
B.CDU-C
C.CDU-C+
D.CDU-D
A.22
B.44
C.8
D.3
E.46
