单选题Supposing 1 million leukemia cells were killed after 24 hours of exposure to radio waves, how many healthy cells would be killed under the same condition?A1.2 million.B1.4 million.C0.8 million.D2 million.
单选题
Supposing 1 million leukemia cells were killed after 24 hours of exposure to radio waves, how many healthy cells would be killed under the same condition?
A
1.2 million.
B
1.4 million.
C
0.8 million.
D
2 million.
参考解析
解析：
数字的找寻和判断。录音中提到“In the Italian study, after 24 hours 20 percent mole leukemia cells died than healthy cells but longer exposure to the radio waves triggered…”，可知暴露在无线电波之下24小时，被杀死的白血病细胞比正常细胞数量多出20%。也就是说，如果有1 million（100万）个白血病细胞被杀死，同时也有0.8 million（80万）的正常细胞被杀死。因此选C。
数字的找寻和判断。录音中提到“In the Italian study, after 24 hours 20 percent mole leukemia cells died than healthy cells but longer exposure to the radio waves triggered…”，可知暴露在无线电波之下24小时，被杀死的白血病细胞比正常细胞数量多出20%。也就是说，如果有1 million（100万）个白血病细胞被杀死，同时也有0.8 million（80万）的正常细胞被杀死。因此选C。
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共用题干第二篇Bone Marrow TransplantationBone marrow is the spongy tissue inside some of your bones,such as your hip and thigh bones. It contains immature cells,called stem cells.The stem cells can develop into the red blood cells that carry oxygen through your body,the white blood cells that fight infections,and the platelets that help with blood clotting.If there is a problem with your bone marrow,a transplant can give you healthy new marrow. You could need a transplant because of a disease,such as bone marrow diseases or cancers like leukemia kemia or lymphoma.Or you might need one if a strong cancer treatment kills your healthy blood cells.People with cancer sometimes donate bone marrow before treatment to be transplanted later. But often the new marrow comes from a donor,either a close family member or someone unrelated.The healthy cells for a transplant can come from three sources:bone marrow;peripheral (circulating) blood that has an increased number of healthy blood-forming cells(also called peripheral blood stem cells or PBSC);umbilical cord blood that is collected after a baby is born.If you need an allogeneic transplant,your doctor will look for a marrow donor or cord blood unit that matches your HLA tissue type.HLA stands for human leukocyte antigen,a markei your immune system uses to recognize which cells belong in your body and which do not.Before your body can receive the healthy cells,the diseased cells must be destroyed.This is done using chemotherapy and sometimes radiation. The destruction of diseased cells is called a preparative regimen or a conditioning regimen.On the day of transplant,the cells from the marrow donor or cord blood unit are infused intravenously(go into your body through a large vein).These healthy cells move into the spaces inside your bones where they create new marrow. They grow and make healthy new red blood cells,white blood cells,and platelets.The new marrow usually comes from__________.A:people with cancerB:a family memberC:an organ donorD:a relative or a stranger
共用题干第一篇Human Heart can Make New CellsSolving a longstanding（为时甚久的）mystery, scientists have found that the human heart continues togenerate new cardiac（心脏的）cells throughout the life span, although the rate of new cell production slows with age.The finding,published in the April 3rd issue of Science,could open a new path for the treatment of heart diseases such as heart failure and heart attack,experts say."We find that the beating cells in the heart, cardiomyocytes（心肌细胞）,are renewed," said lead researcher Dr. Jonas Frisen,a professor of stem cell research at the Karolinska Institute in Stockholm,Sweden."It has previously not been known whether we were limited to the cardiomyocytes we were born with or whether they could be renewed,"he said."The process of renewing these cells changes over time,"Frisen added. In a 20-year-old,about 1percent of cardiomyocytes are exchanged each year , but the turnover（更替）rate decreases with age to only 0.45 percent by age 75."If we can understand how the generation of new cardiomyocytes is regulated,it may be potentially possible to develop pharmaceuticals（药物）that promote this process to stimulate regeneration after , for example,a heart attack,"Frisen said.That could lead to treatment that helps restore damaged hearts."A lot of people suffer from chronic heart failure,."noted co-author Dr. Ratan Bhardwaj,also from the Karolinska Institute."Chronic heart failure arises from heart cells dying," he said."With this finding,scientists are opening the door to potential therapies（疗法）,to having ourselves heal ourselves,"Bhardwaj said."Maybe one could devise a pharmaceutical agent that would make heart cells make new and more cells to overcome the problem they are facing."But barriers remain.According to Bhardwaj,scientists do not yet know how to increase heart cell production to a rate that would replace cells faster than they are dying off,especially in older patients with heart failure.In addition,the number of new cells the heart produces was estimated using healthy hearts一 whether the rate of cell turnover in diseased hearts is the same remains unknown.It is not known yet if the rate of cell turnover in diseased hearts_________.A:is high enough to replace cells faster than they're dying offB:is of any use to researchersC:is the same as that in healthy heartsD:changes over time
共用题干第二篇Bone Marrow TransplantationBone marrow is the spongy tissue inside some of your bones,such as your hip and thigh bones. It contains immature cells,called stem cells.The stem cells can develop into the red blood cells that carry oxygen through your body,the white blood cells that fight infections,and the platelets that help with blood clotting.If there is a problem with your bone marrow,a transplant can give you healthy new marrow. You could need a transplant because of a disease,such as bone marrow diseases or cancers like leukemia kemia or lymphoma.Or you might need one if a strong cancer treatment kills your healthy blood cells.People with cancer sometimes donate bone marrow before treatment to be transplanted later. But often the new marrow comes from a donor,either a close family member or someone unrelated.The healthy cells for a transplant can come from three sources:bone marrow;peripheral (circulating) blood that has an increased number of healthy blood-forming cells(also called peripheral blood stem cells or PBSC);umbilical cord blood that is collected after a baby is born.If you need an allogeneic transplant,your doctor will look for a marrow donor or cord blood unit that matches your HLA tissue type.HLA stands for human leukocyte antigen,a markei your immune system uses to recognize which cells belong in your body and which do not.Before your body can receive the healthy cells,the diseased cells must be destroyed.This is done using chemotherapy and sometimes radiation. The destruction of diseased cells is called a preparative regimen or a conditioning regimen.On the day of transplant,the cells from the marrow donor or cord blood unit are infused intravenously(go into your body through a large vein).These healthy cells move into the spaces inside your bones where they create new marrow. They grow and make healthy new red blood cells,white blood cells,and platelets.The word"immature"in paragraph 1 means___________.A:majorB:outstandingC:underdevelopedD:significant
共用题干Just one hour's listening to an MP3 player can damage hearing,claim scientists.It causes temporary changes in hearing sensitivity which may lead to long-term harm,according to a new study.The findings show over -stimulation of hair cells within the ear occurs even at varying volume levels for short periods of time.The study of almost 60 young people carried out by researchers at Ghent University,Belgium,is published in the Archives of Otolaryngology -Head&Neck Surgery journal.It follows previous warnings from doctors that using MP3 players at high volumes with earphones that fit into the ear canal could lead to loss of hearing. In the latest study,21 people aged 19 to 28 years were exposed to pop and rock music using MP3 players at varying volumes for one hour. A second group of 28 men and women were a control group who were not exposed to MP3 music.Hearing tests were carried out before and after the exposure,which found significant threshold or emission shifts were observed between almost every session of the noise exposure group compared with the control group.Lead researcher Hannah Kempler said:Excessive noise exposure can lead to metabolic and mechanical effects resulting in alterations of the structural elements of the inner ear that contains auditory sensory cells or"hair cells".The European Commission has warned up to 10% of 30-year-old would have to wear a hearing device within the next decade because they listen to music too loudly through headphones.Surveys showed more than 90% of young people in Europe and the U.S.used MP3 players,often for several hours a day at maximum volume.Hearing experts recommend the 60/60 rule一listening to MP3 players for no more than 60 minutes at a time at 60% of maximum volume.Concern among EU health and safety officials has led to plan to ensure all MP3 players have the same maximum volume of 85 decibels(dB)一although users may be able to individually override it at their own risk. Not much difference was found between the exposure group and the control group according to the hearing tests after the exposure.A:Right B:Wrong C:Not mentioned
共用题干第二篇Nuclear Power and Its DangerNuclear power's danger to health,safety,and even life itself can be summed up in one word:radiation.Nuclear radiation has a certain mystery about it,partly because it cannot be detected by human senses. It can't be seen or heard,or touched,or tasted,even though it may be all around us.There are other things like that.For example,radio waves are all around us but we can't detect them,sense them,without a radio receiver.Similarly,we can't sense radioactivity without a radiation detector. But unlike common radio waves, nuclear radiation is not harmless to'human beings and other living things.At very high levels,radiation can kill an animal or human being outright by killing masses of cells invital organs.But even the lowest level of radiation can do serious damage.There is no level of radiation that is comnpletely safe.If the radiation does not hit anything important,the damage may not be significant.This is the case when only a few cells are hit,and if they are killed outright.Your body will replace the dead cells with healthy ones.But if the few cells are only damaged,and if they reproduce themselves,you may be in trouble.They reproduce themselves in a deformed way.They can grow into cancer. Sometimes this does notshow up for many years.There is another reason for the mystery of nuclear radiation.Serious damage can be done without the victim being aware at the time that damage occurs. A person can be irradiated and feel fine,then die of cancer five,ten,or twenty years later as a result.Or a child can be born weak or liable to serious illness as a result of radiation absorbed by its grandparents.Radiation can hurt us.We must know the truth.Radiation can cause serious consequences even at the lowest level_______________.A:when it kills a few cellsB:if it damages a few cellsC:though the damaged cells can repair themselvesD:unless the damaged cells can reproduce themselves
单选题How many African elephants were there in 1979?AAbout 10 million,BAbout 9 million,CAbout 1 million,DAbout 600,000.
单选题According to the passage, what would happen to healthy cells within 48 hours of exposure to radio waves?AThe number of healthy cells will keep declining as more and more of them die.BThe number of healthy cells will initially drop before recovering rapidly.CThe number of healthy cells will be on steady increase throughout the process.DThe scientists have not yet arrived at any conclusion on this issue.
单选题How many blind people should not have to suffer with medical knowledge and skills today?A14 million.B42 million.C28 million.D200 million.
单选题Two teenagers can paint a garage in 6 hours. How many hours would it take 3 teenagers to paint the same garage?A3/2B5/2C8/3D3E4