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更多“心率（heart rate)”相关的问题
Human Heart Can Make New Ceils
Solving a longstanding (为时甚久的) mystery, scientists have found that the human heart continues to generate 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 3 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 are born with or if they could be renewed," he said.
The process of renewing these cells changes over time, Frisen added. In a 20-year-old, about 1 percent 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 -- whether the rate of cell turnover in diseased hearts is the same remains unknown.
The human heart stops producing cardiac cells
A．when a person becomes old.
B．as soon as a person gets sick.
C．immediately after a person is born.
D．once a person dies.
A.for short
B.for all
C.for example
D.for instance
What is the proper title of the passage？
A．Heart Disease
B．Depression
C．Depression and Fatality Rate
D．Depression Hurts the Heart
A.a The intensity range for a moderate exercise actity is usually over 80 percent Of the oxygen uptake reserve中等强度运动的强度范围通常超过得氧量储备的80%。
B.b. The intensity of cardiovascular exercse is identifed by calculating heart rate.心肺训练的强度是通过心率计算来确定。
C.An exercise activily of moderate intensity results in exhaustion for an average untrained healthy adult中等强度的运动会让个末经训练的普通健康成年人筋疲力尽。
D.An exercise intensity of less than 60 percent is required for improvements in overall fitness and conodtoning为了改善整体体能和身体状况，要求运动强度低于60%.
What impressed me most was that they never ______.
A．lost hearts
B．lost their heart
C．lost heart
D．lost their hearts
For his health, he undoubtedly needed a _______ in his heart assoon as possible.
A) surgeon
B) surgery
C) surface
D) supplement
My heart ______ because I thought he was going to dump me for another girl.
A) sink
B) sank
C) sunk
D) sinks
But that is precisely the trouble; for as far as I can see, Mozart's can. Mozart makes me begin to see ghosts, or at the very least ouija-boards. If you read Beethoven's letters, you feel that you are at the heart of a tempest, a whirlwind, a furnace; and so you should, because you are. If you read Wagner's, you feel that you have been run over by a tank, and that, too, is an appropriate response.
But if you read Mozart's—and he was a hugely prolific letter-writer—you have no clue at all to the power that drove him and the music it squeezed out of him in such profusion that death alone could stop it; they reveal nothing—nothing that explains it. Of course it is absurd(though the mistake is frequently made)to seek external causes for particular works of music; but with Mozart it is also absurd, or at any rate useless, to seek for internal ones either. Mozart was an instrument. But who was playing it？
That is what I mean by the Mozart Problem and the anxiety it causes me. In all art, in anything, there is nothing like the perfection of Mozart, nothing to compare with the range of feeling he explores, nothing to equal the contrast between the simplicity of the materials and the complexity and effect of his use of them. The piano concertos themselves exhibit these truths at their most intense; he was a greater master of this form. than of the symphony itself, and to hear every one of them, in the astounding abundance of genius they provide, played as I have so recently heard them played, is to be brought face to face with a mystery which, if we could solve it, would solve the mystery of life itself.
We can see Mozart, from infant prodigy to unmarked grave. We know what he did, what he wrote, what he felt, whom he loved, where he went, what he died of. We pile up such knowledge as a child does bricks; and then we hear the little tripping rondo tune of the last concerto—and the bricks collapse; all our knowledge is useless to explain a single bar of it. It is almost enough to make me believe in — but I have run out of space, and don't have to say it. Put K. 595 on the gramophone and say it for me.
According to Paragraph 1, Cardus observed that ______ .
A．a composer can separate his language and harmonies from his own mind and sensibility
B．a composer can separate his language and harmonies from the mind and sensibility of an artist
C．some people can separate the language and harmonies of a composer from his mind and sensibility
D．the language, harmonies, rhythms, melodies, colors and texture of a composer cannot be separated from each other
Heart failure, for example, appears to have seasonal and temporal patterns. A higher percentage of heart attacks occur in cold weather, and more people experience heart failure on Monday than on any other day of the week. In addition, people are more susceptible to heart attacks in the first few hours after waking. Cardiologists first observed this morning phenomenon in the mid-1980, and have since discovered a number of possible causes. An early-morning rise in blood pressure, heart rate, and concentration of heart stimulating hormones, plus a reduction of blood flow to the heart, may all contribute to the higher incidence of heart attacks between the hours of 8:00 AM and 10:00 AM.
In other studies, both birthdays and bachelorhood have been implicated as risk factors. Statistics reveal that heart attack rates increase significantly for both females and males in the few days immediately preceding and following their birthdays. And unmarried men are more at risk for heart attacks than their married counterparts. Though stress is thought to be linked in some way to all of the aforementioned risk factors, intense research continues in the hope of further comprehending why and how heart failure is triggered.
What does the passage mainly discuss？
A．Risk factors in heart attacks.
B．Seasonal and temporal patterns of heart attacks.
C．Cardiology in the 1980s.
D．Diet and stress as factors in heart attacks.
A．Suffered
B．Suffering
C．Having suffered
D．Being suffered
