They are measured by a unit known as the nanogram, which is one billionth of a gram.    From Wordnik.com.  [LSD and the Third Eye] Reference

KOBILINSKY: A nanogram is a billionth of a gram of DNA.    From Wordnik.com.  [CNN Transcript Feb 16, 2008] Reference

Another type as well called a nanogram strength product.    From Wordnik.com.  [CNN Transcript Dec 10, 2003] Reference

The levels are extremely low, less than a nanogram per gram of fish tissue (a nanogram is a billionth of a gram, and a gram is 1 / 28th of an ounce).    From Wordnik.com.  [AGORAVOX - The Citizen Media] Reference

A nanogram is one billionth of a gram.    From Wordnik.com.  [Molecules of Lactose - the Teeny Tiny Truth] Reference

A nanogram is a billionth of a gram.    From Wordnik.com.  [Newswise: Latest News] Reference

A nanogram is something that is not even visible to the eye.    From Wordnik.com.  [CNN Transcript May 29, 2001] Reference

This is a 207 level nanogram, which a normal people could have as much as a 150 level nanogram.    From Wordnik.com.  [CNN Transcript Jul 17, 2007] Reference

One nanogram (ng) is one billionth of a gram, and one picogram (pg) is one trillionth of a gram.    From Wordnik.com.  [Public Health Statement for Chlorinated Dibenzo-p-dioxins (CDDs)] Reference

Could you cite evidence for this accusation or is last your nanogram of remaining credibility less important than your need to spout inanities?.    From Wordnik.com.  [Hillary Campaign: She Will Not Concede Tonight] Reference

But spouting said argument has a beneficial effect on Jake's endocrine balance. nudging his marginal free serum testosterone up a nanogram or two.    From Wordnik.com.  [Obama: "I Cannot Support" Mukasey For AG] Reference

In airports, explosive detectors are now over a thousand times more sensitive to chemical reagents and can detect quantities down to the nanogram.    From Wordnik.com.  [Nanotech Takes On Homeland Terror] Reference

But what we do know is that since the agreed framework has been in place, they have not been able to separate one additional nanogram of plutonium.    From Wordnik.com.  [Briefing On North And South Korea Nuke Energy Accord] Reference

A 25 millisecond brain event (i.e. occurring in coherent 40 Hz oscillations) would require nanogram (10-9 gram) amounts of superposed neural mass. link.    From Wordnik.com.  [Coordinated Evolution] Reference

EPA advises that children should not have more than 1 nanogram 2,3,7,8-TCDD per liter of water (ng/L) (ppt) in 1 day, or more than 0.01 ng/L per day for long-term exposure.    From Wordnik.com.  [Public Health Statement for Chlorinated Dibenzo-p-dioxins (CDDs)] Reference

Also,the quantities are pretty small and the digestive has a lot of detoxification processes built in, which will say: I sneer at these nanogram quantities of peroxynitrates.    From Wordnik.com.  [Making Light: Snowpocalypse Part Next] Reference

It only takes as much as one nanogram of urushiol to cause an infection.    From Wordnik.com.  [CreationWiki - Recent changes [en]] Reference

The PCB concentration on Aconcagua was less than half a nanogram per litre.    From Wordnik.com.  [PhysOrg.com - latest science and technology news stories] Reference

Gene expression arrays can be obtained with sub-nanogram input of total RNA.    From Wordnik.com.  [BioMed Central - Latest articles] Reference

The amount of plant hormone contained in one gram of plant tissue is only one nanogram.    From Wordnik.com.  [innovations-report] Reference

China's national standard for dioxin emissions allows one nanogram per cubic metre -- 10.    From Wordnik.com.  [Yahoo! News: Business - Opinion] Reference

They found the snow contained low concentrations of PCBs, less than half a nanogram per liter.    From Wordnik.com.  [EcoEarth.Info Environment RSS Newsfeed] Reference

China requires that incinerators discharge no more than one nanogram of dioxin per cubic metre.    From Wordnik.com.  [Chinalyst - China blogs in English] Reference

(A nanogram is one-billionth of a gram and a milliliter is a unit of volume equal to one thousandth of a liter.).    From Wordnik.com.  [Thoroughbred News | BloodHorse.com] Reference

Test results showed he was just 0.9 of a nanogram, basically a particle of dust, over the allowed limit for the drug.    From Wordnik.com.  [canada.com Top Stories] Reference

Test results showed he was just 0.9 of a nanogram, basically a particle of dust, over the allowed limit for nandrolone.    From Wordnik.com.  [canada.com Top Stories] Reference

I know a nanogram is 1 billionth of a gram but the article doesn't seem to give any reference as to what this is in relation to.    From Wordnik.com.  [SplicedFeed] Reference

It only takes one nanogram (ng) of steroids per liter of water to disrupt the endocrinal system of fish and decrease their fertility.    From Wordnik.com.  [Health News from Medical News Today] Reference

Is 0.3 nanograms (a nanogram is one-billionth of a gram) at Cape Grim in Australia, it is 800.    From Wordnik.com.  [SciDev.Net] Reference

I mean, you know, like a nanogram.    From Wordnik.com.  [Jon Stewart's 'Daily Show' has exploded beyond its humble late-night comedy roots] Reference

A nanogram is one thousand millionth of a gram.    From Wordnik.com.  [ANC Daily News Briefing] Reference

They've matured, if by a nanogram.    From Wordnik.com.  [Yahoo! News: Business - Opinion] Reference

(A nanogram is one billionth of a gram.).    From Wordnik.com.  [Junkfood Science] Reference

(a nanogram is one billionth of a gram).    From Wordnik.com.  [EcoEarth.Info Environment RSS Newsfeed] Reference

American Idol season feels - to create it. http: / / www. thefreedictionary.com / nanogram.    From Wordnik.com.  [The Full Feed from HuffingtonPost.com] Reference