Double
Vision 

   
As a kid growing up in the rolling hills of central Georgia, Michael Grace
loved to walk around with a pocket full of snakes.

   
"Most people were terrified of them," including his mom, which
made life around the Grace home a little awkward at times, he says all
these years later.

   
But to a kid in Georgia, that just made snakes all the more interesting.

   
As the years passed he turned his hobby into a profession. Now, he spends
his time probing the world of snakes in his laboratory at the Florida
Institute of Technology in Melbourne.

 双视力

   
   
当Michael
Grace还是个生活在佐治亚州中部起伏山陵上的孩子时，他就喜欢拎着整整一袋蛇，四处游荡。

   
  
多年后，他记忆犹新地说："许多人都怕蛇"，包括他的母亲，那时，蛇为他们家的生活添了不少麻烦。

   
   
可在一个佐治亚州孩子的眼里，这反倒增添了玩蛇的乐趣。

   
  
现在，他的爱好变成了职业。目前，在Melbourne佛罗里达技术研究所的实验室中，他把时间用在研究全世界的蛇。  

  
The secrets he is learning from the fascinating reptiles that live in his
lab could someday lead to major advancements in everything from heat
seeking missiles for the military to tiny devices that might help
physicians locate tumors in the human body.

  That's
because pit vipers, like rattlesnakes, and the group of snakes including
pythons or boas can literally see the world in two different ways. They
can use their eyes to create a visual image of the world around them, just
like humans do, or they can use their extraordinarily sensitive infrared
sensors to create a similar image based upon heat emitted by objects in
their environment.

       
总有一天，他从生活在他实验室中的这种神奇爬行动物身上得到的秘密，将导致多领域的重大科学进步，从军事上的热敏追踪导弹，到可以帮助医生在人体内定位肿瘤的微小探头。

   
   
这是因为响尾蛇科毒蛇（如响尾蛇）和包括蟒蛇在内的一类蛇，可以用两种方式看世界。它们用眼睛获得周围世界的视觉影像，这点和人类相同，但蛇还能用它们异常敏感的红外线感受器，依靠周围物体发出的热量获得相似的视觉影像。

They can
switch back and forth between those two systems, or use both
simultaneously, giving them a leg up, so to speak, when it comes to
targeting a warm object.

   
What has intrigued Grace for years now is how snakes are able to do so
much with so little.       A rattlesnake,
for instance, has one small pit on each side of its head, filled with
thousands of receptor cells, which are actually microscopic-sized infrared
sensors. Yet despite their tiny size, the sensors are at least 10 times
more sensitive than the best artificial infrared sensors that have ever
been built, says Grace, a biology professor at Florida Tech.

  
 Unlike artificial sensors, they don't require an elaborate cooling
system, and they can repair themselves if damaged.

   
All of which set Grace to thinking.

        
它们可以轮流使用这两种系统，或同时使用，帮助它们正确无误地攻击一个发热的猎物。

   
    
多年来，一直引起Grace兴趣的是，蛇是如何能轻而易举地做成这么多事。例如响尾蛇在头部两侧小凹坑里的器官充满数千个受体细胞，这实际上就是显微的红外线感受器。佛罗里达技术研究所的生物学教授Grace说，尽管它们很微小，但与目前人类已制造出的最好的人工红外线感受器相比，蛇感受器的敏感性至少要高出10倍。

    
    
不象人工感受器，蛇的感受器不需要复杂的冷却系统，它们能自我修复损伤。

        
所有这些都引起Grace的思考。

 
"If you can build a sensor that's based upon the cell biology and
biochemistry" of snakes, he says, "you could make some
extraordinary advancements in artificial sensor technology."

   
So a couple of years ago he landed a $365,800 three-year grant from the
U.S. Air Force Office of Scientific Research to see just what snakes might
be able to tell us about infrared vision. That could come in handy for
such things as a heat-seeking missile that could fly up the exhaust valve
of an enemy aircraft without revealing its presence.

         
他说："如果你能制造成以蛇的细胞生物学和生物化学为基础的感受器，你就能使人工感受器技术显著发展。"

   
   
为此，几年前，他从美国空军科学研究办公室弄到了365,000美元的三年期拨款，专门研究蛇红外线视力的秘密，希望能搞出一些小玩意，如能悄无声息地钻入敌机排气阀内的热追踪导弹。

 Grace's
personal quest, however, was more in the line of scientific curiosity. He
just wanted to learn how these animals are able to convert infrared
radiation - or heat - into a signal that can be processed by the central
nervous system, giving the snake a second source of vision.

  He
wanted to know which system is most important to the snake, eyes or
infrared sensors? Can snakes get by with just one system if the other
fails? Can they switch back and forth between the two systems?

        
然而，Grace个人追求则更多在于对科学的好奇。他只想知道蛇是如何把红外线幅射或热转变为中枢神经系统能处理的信号，这使蛇有了第二视力。

  
    
他想知道，对蛇来说，眼睛或红外线哪一种系统更重要？假如一种系统失败了，蛇能仅靠一种视觉系统生存吗？它们能在两个系统之间转换吗？

The
infrared sensors are actually receptor cells in the pit organ, and the
research indicates that they come in different varieties, possibly to
"look" at different wavelengths in the infrared. That would give
the snake a sort of "color vision," according to Atsuko
Matsushita, a visiting scientist at Florida Tech who is working on the
project.

   
With the help of the electrical tape, the researchers found that their
subjects were able to get along quite nicely, even if temporarily
impaired. If they blocked out the eyes, the snakes functioned with just
their infrared sensors. If the researchers knocked out those sensors, the
snakes used their eyes.

   
   
在佛罗里达技术实验室参与此研究计划的Atsuko
Matsushita介绍说，红外线感受器实际上是蛇头部凹形器官内的受体细胞。研究表明，它们来自不同类型，可能为了接受红外线中不同的波长，这使蛇具有"彩色视力"。

  
     
在电子记录带的帮助下，研究人员发现受试的蛇即使暂时受伤也能够应付自如。假如它们不用眼睛，就启用红外线感受器。如果研究人员除掉这些感受器，蛇就用眼睛了。

 Thus
the snakes were able to switch back and forth between the two systems. All
of this suggests that the reward for borrowing technology from snakes may
be very high indeed.

   
Grace believes that if we could somehow replicate the extremely sensitive
infrared sensors of the pit viper, it might be possible to detect very
small temperature changes in parts of the human body. A tumor, for
example, requires an increased flow of blood to grow, possibly resulting
in a slightly elevated temperature around the tumor.

   Any
change would be so small, Grace says, that "no detectors that we have
available now would be able to detect it." But a snake might know
it's there. Someday, because of what snakes might be able to teach us, a
physician might also find that tumor before it spreads.   ABCNEWS

         
如此看来，蛇能够在两种系统之间转换自如。所有的这些发现都提示仿生蛇的技能可获益匪浅。

       
Grace相信，如果我们有一天能复制出象响尾蛇科那种极端敏感的红外线感受器，也许能检测出人体各种部位的微小温度变化。例如，肿瘤需要血流才能生长，这就会引起肿瘤周围的温度轻微升高。

    
    
Grace说，这种变化非常之小，"目前我们没有检测仪能发现这种温度的改变。"
但是蛇自己或许知道。总有一天，由于蛇对我们的"教诲"，医生能在肿瘤扩散前就发现它。美国广播公司  朔如
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