有关99mTc的标记下列哪项不正确（） A.99mTc的标记有直接标记法_爱下问搜题

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问题单项选择题

有关^99mTc的标记下列哪项不正确（）

A.^99mTc的标记有直接标记法和配体交换法

B.还原剂的量与^99mTc标记无关

C.还原剂的pH值对^99mTc标记非常重要

D.^99mTc与配体的络合能力随配体浓度和酸度等条件不同而变化

E.常用的中间配体有：酒石酸、柠檬酸、葡庚糖、MDP

答案

参考答案：B

解析：还原剂的量与^99mTc标记密切相关，还原剂太少还原反应不完全，还原剂太多易形成还原水解锝，亦影响放化纯度。

单项选择题

利多卡因用于治疗哪种心律失常较有效

A．心房扑动

B．室上速

C．室性早搏

D．心房颤动

E．房性心动过速

完形填空

The Voice of America began during the World War II. When Germany was broadcasting a radio program to get international 36 , American officials believed they should 37 the German broadcast with words that they thought were the facts of world events. The first VOA news report began with words in 38 . “The 39 may be good or bad, but we shall tell you the truth.” Within a week, other VOA 40 were broadcasting in Italian, French and English.
After the World War II ended in 1945, some Americans felt VOA’s 41 had to be changed, 42 the Soviet Union became enemy of America. They wanted to 43 Soviet listeners. Then VOA began broadcasting in Russian.
In the early years VOA began adding something new to its broadcast that was 44 “ Music USA”. Another new idea came along in 1959. VOA knew that many listeners did not know 45 English to completely understand its 46 English broadcast. So VOA 47 a simpler kind of English, 48 uses about 1,500 words and is spoken 49 of course, it is special English.
In the 50 of most VOA listeners, the most 51 program is the news report. News from around the world 52 into the VOA news rooms in Washington 24 hours a day. It comes from VOA reporters in 53 cities and also from other 54 like BBC. VOA writers and editors use these materials to 55 news reports, which are being broadcast in 43 languages.

D．information

C．considering

D．in order that