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科学美国人60秒:视力和重碳酸盐之间的微妙关系

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Most carbon dioxide that travels from your muscles to your lungs for exhalation does so not as CO2 proper, but as part of bicarbonate:
HCO?—Bicarbonate's vital to maintaining your blood pH, and it also aids in digestion.
But it turns out bicarbonate also tweaks the activity of rod cells in your retina.
In everyday vision, photons flood your rod cells, setting off a chemical cascade that eventually translates into an electrical message about what you saw.
But in lab tests, higher than normal levels of bicarbonate allow the rods to recover from that photon response 30 percent faster.
A 30 percent higher refresh rate, essentially—meaning your ability to detect movement would improve.
The downside?
This rapid reset of the rod cells means they're less sensitive to light.
"If you're sitting in darkness and you turned on a steady light, it might now take brighter light for you to say,I can see that."
Study author Clint Makino, of the Massachusetts Eye and Ear Infirmary and Harvard Med School.
"Or if the light's already on, it would take a larger increment in intensity for you to say,Ok, it looks brighter now."
The results are in the Journal of Biological Chemistry.
Makino says heavy exercise—which causes a boost in CO2—might even alter the body's bicarbonate enough to trigger a measurable effect on the eye.
"I don't think it's known whether your vision changes under conditions of vigorous exercise.
So that'll be an interesting question for the experimental psychologists and the psychophysicists."
And if you're eyeing your club soda as a shortcut to CO2?
He says most of those bubbles never make it past the belch.

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重点单词   查看全部解释    
alter ['ɔ:ltə]

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v. 改变,更改,阉割,切除

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refresh [ri'freʃ]

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v. 使 ... 生气蓬勃,提起精神,恢复精神

 
belch [beltʃ]

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v. 打嗝,喷出

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response [ri'spɔns]

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n. 回答,响应,反应,答复
n. [宗

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intensity [in'tensiti]

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n. 强烈,强度

 
exhalation [.ekshə'leiʃən]

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n. 呼气,蒸发,散发物

 
setting ['setiŋ]

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n. 安装,放置,周围,环境,(为诗等谱写的)乐曲

 
eventually [i'ventjuəli]

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adv. 终于,最后

 
measurable ['meʒərəbəl]

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adj. 可测量的

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essentially [i'senʃəli]

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adv. 本质上,本来

 

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