Causes of vitamin D deficiency include intestinal malabsorption which can be seen with celiac disease or Crohn's disease, not enough UV light exposure, like in homebound, elderly populations.

引起维生素D缺乏的因素包括：小肠吸收不，于乳糜泻和克罗恩病；紫外线照射不足，常于久居家中的老年人。

Certain pigments glow under UV light, exposing traces that would have been otherwise invisible.

某些色素在紫外线下会发光，暴露出原本看不的痕迹。

When we lay in the sun, our skin absorbs two types of UV light.

当我们在阳光下躺在的时候，我们的皮肤会吸收两种紫外线。

The sun's activity waxes and wanes on an 11-year cycle, and over this cycle the amount of ultraviolet (UV) light the sun emits changes a lot more than does the total amount of energy.

太阳的活动周期是11年，在此周期内太阳散发出的紫外线总量的变化比太阳能总量的变化要大的多。

In several places, there are large holes that let in pure UV light.

在几个地方，甚至出现了臭漏洞，导致太阳直射。

When skin is exposed to UV for long periods of time, the UV light damages the DNA within our cells, and skin starts to burn.

他们的皮肤长期暴露在紫外线下，紫外线会破坏细胞内的DNA并灼伤皮肤。

When it's bright and sunny like this, my eyes struggle to cope with the amount of UV light that's coming from the sun and is bouncing back up off the snow.

在这样阳光明媚的天气里，我的眼睛很难承受来自太阳并从雪地上反射回来的大量紫外线。

And just to look at the sheer numbers globally, they're just much larger pool of options that manufacturers can draw from, which helps the consumer because they're just more products out there, they're protecting a wider range of UV light.

仅从全球数目繁杂的品类来看，紫外线防晒剂是制造商以提取的大部分选择，这对消费者有益，因为它们以有更多的产品，它们更大范围的紫外线。

It's actually easier than it sounds to look for scorpions on a moonless night because they have these fluorescent compounds in their exoskeletons and they glow under UV light.

在没有月亮的夜晚寻找蝎子实际上比听起来更容易，因为它们的外骨骼中含有这些荧光化合物，它们会在紫外线下发光。

The UV light that we get here is so intense, and it really drives the activity of the butterflies, and it supports all of the plants.

这里紫外线十分强烈，这样蝴蝶会更愿意出来活动，植物也生长得更好。

And there is actually insects that come in because we run a UV light and then they can practice on their own.

事实上，昆虫也会进来，因为我们使用紫外线灯，它们就以自己练习了。

Under the thick coat of fur, the skin of the polar bear is actually black, which helps them to absorb the UV light.

在厚厚的皮毛之下，北极熊的皮肤实际上是黑色的，这有助于它们吸收紫外线。

Most bats have decent vision and some species like fruit bats actually have particularly good vision and can even see UV light.

大多数蝙蝠的视力都不错，而像果蝠这样的物种其实视力特别好，甚至以看到紫外线。

Right. And finally, there's air disinfection — for example, using UV light to " kill" or inactivate a virus in the air.

是的。最后一个重点是“空气消毒”——比如使用紫外线灯“杀死”空气中的病毒或使其失去活性。

Finally, the tech turns the UV light back on, and sees how much longer the participants last before turning red again.

最后，技术人员再次打开紫外线灯，观察参与者的皮肤经过多久会再次变红。

It's dark green because they have this particular pigment protecting them from the access of UV light.

这是深绿色的, 因为它们有这个特殊的色素自己不受紫外线的侵害。

Over 100 years ago, UV light was first used to disinfect drinking water in Masse, France.

100多年前，紫外线在法国马赛首次被用于净化饮用水。

But before the UV lights turn on, safety measures are taken.

但是在打开紫外线灯之前，要采取安全措施。

All forms of UV light are known to be harmful to the skin and to the eyes.

众所周知，所有形式的紫外线都对皮肤和眼睛有害。

In a sunburn, certain kinds of UV light also damage your DNA, and your immune system starts killing off malfunctioning cells so they don't become cancerous.

在晒伤的情况下，某些紫外线也会损伤你的DNA，然后你的免疫系统会开始杀死这些不正常的细胞以防它们产生癌变。