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SCIENCE IN THE NEWS - Cloning in South Korea / Ancient Insec

时间:2006-03-01 16:00来源:互联网 提供网友:SZPJX   字体: [ ]
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SCIENCE IN THE NEWS - Cloning in South Korea / Ancient Insect / Preeclampsia Research
By

Broadcast: Tuesday, March 09, 2004

(THEME)

VOICE ONE:

This is Science in the News, in VOA Special English. I'm Sarah Long.

VOICE TWO:

And I'm Bob Doughty1. This week, something new and something old ... the debate over the cloning of human embryos3, and the discovery of the oldest insect ever found.

VOICE ONE:

Plus, some hopeful news from research on a dangerous disorder4 of pregnancy5.

(THEME)

VOICE TWO:

 
Hwang Woo-suk, center, and Moon Shin-yong talk to Donald Kennedy, editor-in-chief of Science magazine, Feb. 12 at the American Association for the Advancement6 of Science meeting in Seattle.
Two doctors in South Korea are in the news a lot these days. They are the first scientists to report success in efforts to create a human embryo2 and to remove stem cells from it. Stem cells have the ability to grow into other cells, such as heart, nerve or brain cells. So they might offer new ways to treat disease.

Hwang Woo-suk and Moon Shin-yong are doctors at Seoul National University. Their study was published in February in Science magazine.

Sixteen women took part in the research. They agreed to take fertility drugs for a month. These caused them to produce a large number of eggs. The doctors collected two-hundred-forty-two eggs for their study.

 
Injection of a donor7 cell.
They removed the nucleus8 from each cell in the eggs. The nucleus contains DNA9 material, the complete genetic11 plans for an organism. Then the researchers used electricity to join each egg cell to a different cell taken from the women's ovaries. The ovaries are the organs that produce eggs.

Thirty of the joined cells grew into what are called blastocysts, an early form of an embryo. The doctors say they were able to collect stem cells from twenty of them.

VOICE ONE:

 
Cloned embryo at four-cell stage.
There are many political and moral questions about this work. Lawmakers around the world remain divided over how to supervise cloning research. But scientists, politicians and clergy12 generally agree that cloning should not be used to copy human beings.

It has been done with animals. In each case, scientists created an embryo and placed it in a female animal to grow. There was Dolly the cloned sheep, for example. This form of science is called reproductive cloning.

But many scientists do support therapeutic13 cloning for humans. This is where stem cells are harvested for research on possible treatments for disease. Supporters argue that cloned stem cells could be used for gene10 therapy or to repair tissue. Researchers say they are still years away from such uses. Yet critics say they fear that human embryos could become just another industrial product.

Some people would ban any form of cloning.

VOICE TWO:

Doctor Hwang says he understands the issues about his research. But he says human embryo cloning must go forward to help people with deadly diseases.

The two doctors are seeking patent ownership rights to the process they developed. They say they also want to protect the cloned human stem cells that grew from their experiments.

Seoul National University will own sixty percent of the patent. Organizations that helped finance the research will own forty percent.

Hwang Woo Suk and Moon Shin Yong say they are not seeking any economic gains in the future. They say their only hope is that one day, their discovery will help solve some incurable14 disease.

VOICE ONE:

Last week, there was a separate development in the United States. Harvard University announced plans to build a center to grow and study human stem cells. Harvard officials in Cambridge, Massachusetts, say they will pay for the center with private money.

The Bush administration bars the use of federal money for stem cell research. This is because a developing embryo must be destroyed in order to collect the cells. Opponents of such research say this destroys life.

(MUSIC BRIDGE)

VOICE TWO:

Some pregnant women develop a condition called preeclampsia [pre-ee-CLAMP-see-ah]. This causes dangerously high blood pressure. It causes the urine to contain large amounts of protein. And it causes fluid to collect in the hands and feet. Preeclampsia can threaten the life of the mother and her baby. In severe cases, the woman can suffer seizures15 and die.

Doctors can treat the effects. But the only cure known is giving birth. However, babies born to mothers with preeclampsia may be small for their age. Or they may be born too soon. This puts the baby at risk for a number of problems.

Researchers say preeclampsia affects about five percent of pregnancies16. It can happen without warning. The cause is unknown. But new findings may help doctors look for signs of preeclampsia before it happens, and do more about it.

VOICE ONE:

A study found that two proteins in the blood may point to the development of preeclampsia. The New England Journal of Medicine published the findings last month. Researchers from the National Institutes of Health and Harvard Medical School did the study.

They studied protein levels in blood taken from one hundred-twenty women who had preeclampsia. The blood had been taken throughout their pregnancies. They compared the findings to the blood of one-hundred-twenty other women who had not developed preeclampsia.

The two groups began their pregnancies with similar levels of the two proteins measured. But the researchers found that changes took place in the women who later developed preeclampsia.

Levels of one protein began to increase about five weeks before the women showed any signs of the condition. Also, levels of the other protein decreased beginning in the thirteenth and sixteenth weeks of their pregnancies.

VOICE TWO:

Doctor Richard Levine of the National Institute of Child Health and Human Development led the study. He notes that the study did not include women who developed pregnancy-related high blood pressure but not preeclampsia. So it is not known if these women have similar changes in their proteins.

But Doctor Levine says the findings do offer the possibility of preventing and treating preeclampsia.

(MUSIC BRIDGE)

VOICE ONE:

Have you heard about the world's oldest insect? Scientists say a small bug17 found in Scotland is four-hundred-million years. No, it is not still alive. The finding suggests that insects existed on Earth twenty-million years earlier than thought. It also suggests they were among the first living creatures on land.

The insect was first discovered about eighty years ago. But there was little interest until two-thousand-two. Then, two scientists rediscovered it while doing other research. They examined the fossil at the Natural History Museum in London.

The two are David Grimaldi of the American Museum of Natural History in New York and Michael Engel of the University of Kansas. They examined the remains18 under a powerful microscope. Details of their discovery appear in Nature magazine.

VOICE TWO:

The scientists say the insect was probably just over one-half centimeter long. It may have been about the size of a grain of rice and looked like a small fly. The insect was found in red sandstone called chert. The scientists say the insect probably became trapped in crystals that formed around a hot spring.

They examined parts of the head and body. Mister Grimaldi says the jaws20 proved it was an insect. He says the jaws were very similar to those found only in insects with wings. He says he and Mister Engel became excited at the idea that the insect may have flown.

They did not find any wings. However, Mister Grimaldi says the jaw19 parts, or mandibles, provide strong evidence that it had them.

VOICE ONE:

Other scientists agree that this is the oldest insect found so far. But not all agree that it flew. The oldest known flying insects -- at least until now -- date back about three-hundred-twenty million years.

Until now, the oldest insect fossils on record were two insects without wings. They are said to be about three-hundred-eighty million years old. They were found in New York State and Canada.

The four-hundred-million-year-old insect is known by the Latin name Rhyniognatha hirsti. Mister Grimaldi says the finding suggests that insects likely developed during the Silurian period. This is the period when evidence shows that plants began to appear on land.

(THEME)

VOICE TWO:

SCIENCE IN THE NEWS, in VOA Special English, was written by Jill Moss21, Lawan Davis and Cynthia Kirk, who was also our producer. This is Bob Doughty.

VOICE ONE:

And this is Sarah Long. Listen again next week, when we throw some light on the dark ... dark energy, that is. Scientists say it appears to support a theory that Albert Einstein once proposed, and then rejected.


点击收听单词发音收听单词发音  

1 doughty Jk5zg     
adj.勇猛的,坚强的
参考例句:
  • Most of successful men have the characteristics of contumacy and doughty.绝大多数成功人士都有共同的特质:脾气倔强,性格刚强。
  • The doughty old man battled his illness with fierce determination.坚强的老人用巨大毅力与疾病作斗争。
2 embryo upAxt     
n.胚胎,萌芽的事物
参考例句:
  • They are engaging in an embryo research.他们正在进行一项胚胎研究。
  • The project was barely in embryo.该计划只是个雏形。
3 embryos 0e62a67414ef42288b74539e591aa30a     
n.晶胚;胚,胚胎( embryo的名词复数 )
参考例句:
  • Somatic cells of angiosperms enter a regenerative phase and behave like embryos. 被子植物体细胞进入一个生殖阶段,而且其行为象胚。 来自辞典例句
  • Evolution can explain why human embryos look like gilled fishes. 进化论能够解释为什么人类的胚胎看起来象除去了内脏的鱼一样。 来自辞典例句
4 disorder Et1x4     
n.紊乱,混乱;骚动,骚乱;疾病,失调
参考例句:
  • When returning back,he discovered the room to be in disorder.回家后,他发现屋子里乱七八糟。
  • It contained a vast number of letters in great disorder.里面七零八落地装着许多信件。
5 pregnancy lPwxP     
n.怀孕,怀孕期
参考例句:
  • Early pregnancy is often accompanied by nausea.怀孕早期常有恶心的现象。
  • Smoking during pregnancy increases the risk of miscarriage.怀孕期吸烟会增加流产的危险。
6 advancement tzgziL     
n.前进,促进,提升
参考例句:
  • His new contribution to the advancement of physiology was well appreciated.他对生理学发展的新贡献获得高度赞赏。
  • The aim of a university should be the advancement of learning.大学的目标应是促进学术。
7 donor dstxI     
n.捐献者;赠送人;(组织、器官等的)供体
参考例句:
  • In these cases,the recipient usually takes care of the donor afterwards.在这类情况下,接受捐献者以后通常会照顾捐赠者。
  • The Doctor transplanted the donor's heart to Mike's chest cavity.医生将捐赠者的心脏移植进麦克的胸腔。
8 nucleus avSyg     
n.核,核心,原子核
参考例句:
  • These young people formed the nucleus of the club.这些年轻人成了俱乐部的核心。
  • These councils would form the nucleus of a future regime.这些委员会将成为一个未来政权的核心。
9 DNA 4u3z1l     
(缩)deoxyribonucleic acid 脱氧核糖核酸
参考例句:
  • DNA is stored in the nucleus of a cell.脱氧核糖核酸储存于细胞的细胞核里。
  • Gene mutations are alterations in the DNA code.基因突变是指DNA密码的改变。
10 gene WgKxx     
n.遗传因子,基因
参考例句:
  • A single gene may have many effects.单一基因可能具有很多种效应。
  • The targeting of gene therapy has been paid close attention.其中基因治疗的靶向性是值得密切关注的问题之一。
11 genetic PgIxp     
adj.遗传的,遗传学的
参考例句:
  • It's very difficult to treat genetic diseases.遗传性疾病治疗起来很困难。
  • Each daughter cell can receive a full complement of the genetic information.每个子细胞可以收到遗传信息的一个完全补偿物。
12 clergy SnZy2     
n.[总称]牧师,神职人员
参考例句:
  • I could heartily wish that more of our country clergy would follow this example.我衷心希望,我国有更多的牧师效法这个榜样。
  • All the local clergy attended the ceremony.当地所有的牧师出席了仪式。
13 therapeutic sI8zL     
adj.治疗的,起治疗作用的;对身心健康有益的
参考例句:
  • Therapeutic measures were selected to fit the patient.选择治疗措施以适应病人的需要。
  • When I was sad,music had a therapeutic effect.我悲伤的时候,音乐有治疗效力。
14 incurable incurable     
adj.不能医治的,不能矫正的,无救的;n.不治的病人,无救的人
参考例句:
  • All three babies were born with an incurable heart condition.三个婴儿都有不可治瘉的先天性心脏病。
  • He has an incurable and widespread nepotism.他们有不可救药的,到处蔓延的裙带主义。
15 seizures d68658a6ccfd246a0e750fdc12689d94     
n.起获( seizure的名词复数 );没收;充公;起获的赃物
参考例句:
  • Seizures of illicit drugs have increased by 30% this year. 今年违禁药品的扣押增长了30%。 来自《简明英汉词典》
  • Other causes of unconsciousness predisposing to aspiration lung abscess are convulsive seizures. 造成吸入性肺脓肿昏迷的其他原因,有惊厥发作。 来自辞典例句
16 pregnancies 2fedeb45162c233ee9e28d81888a2d2c     
怀孕,妊娠( pregnancy的名词复数 )
参考例句:
  • Since the wartime population needed replenishment, pregnancies were a good sign. 最后一桩倒不失为好现象,战时人口正该补充。
  • She's had three pregnancies in four years. 她在四年中怀孕叁次。
17 bug 5skzf     
n.虫子;故障;窃听器;vt.纠缠;装窃听器
参考例句:
  • There is a bug in the system.系统出了故障。
  • The bird caught a bug on the fly.那鸟在飞行中捉住了一只昆虫。
18 remains 1kMzTy     
n.剩余物,残留物;遗体,遗迹
参考例句:
  • He ate the remains of food hungrily.他狼吞虎咽地吃剩余的食物。
  • The remains of the meal were fed to the dog.残羹剩饭喂狗了。
19 jaw 5xgy9     
n.颚,颌,说教,流言蜚语;v.喋喋不休,教训
参考例句:
  • He delivered a right hook to his opponent's jaw.他给了对方下巴一记右钩拳。
  • A strong square jaw is a sign of firm character.强健的方下巴是刚毅性格的标志。
20 jaws cq9zZq     
n.口部;嘴
参考例句:
  • The antelope could not escape the crocodile's gaping jaws. 那只羚羊无法从鱷鱼张开的大口中逃脱。
  • The scored jaws of a vise help it bite the work. 台钳上有刻痕的虎钳牙帮助它紧咬住工件。
21 moss X6QzA     
n.苔,藓,地衣
参考例句:
  • Moss grows on a rock.苔藓生在石头上。
  • He was found asleep on a pillow of leaves and moss.有人看见他枕着树叶和苔藓睡着了。
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