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Once again the time has come for one and all to gather around. Science talk is here. New discoveries, new takes on old knowledge, and other bits of news are all available for the perusing in today's information world. Over the fold are selections from the past week from a few of the many excellent science news sites around the world. Today's tidbits include new contrast agents detect bacterial infection with high sensitivity and specificity, diamonds aren't forever, discovery of the farthest and largest water mass in the universe, fool's gold helps show how earth evolved, and a heavy relative of the neutron discovered.  Gather yourselves around. Pull up that comfy chair and bask in the sunshine. There is plenty of room for everyone. Get ready for one more session of Dr. Possum's science education and entertainment.

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Featured Stories
In humans bacterial infection is a leading cause of limb amputation.  A new generation of imaging agents may lead to better treatment protocols in our future.

In experiments using a rat model, the researchers found that the contrast agent accumulated in bacteria-infected tissues, but was efficiently cleared from uninfected tissues. They saw a 42-fold increase in fluorescence intensity between bacterial infected and uninfected tissues. However, the contrast agent did not accumulate in the healthy bacterial microflora located in the intestines.  Because systemically administered glucose molecules cannot access the interior of the intestines, the bacteria located there never came into contact with the probe.

They also found that the probes could detect as few as one million viable bacteria cells. Current contrast agents for imaging bacteria require at least 100 million bacteria, according to the researchers.

Long considered a forever substance diamonds have been found to evaporate under certain light conditions.
The diamonds were exposed to intense light pulses in the UV-C band (the harsh ultraviolet rays filtered out by the ozone layer), and small pits in the diamond surface were visible after only a few seconds. The rate of mass loss in the diamond fell notably for lower light levels but the etching process still continued - albeit at a slower and slower pace, (researcher) Mildren said.

But before diamond lovers around the world start to panic, he is quick to note that the rate of evaporation is very small and not noticeable under normal conditions. In fact, even under very bright UV conditions, such as intense sunlight or under a UV tanning lamp, it would take approximately the age of the universe - about 10 billion years - to see an observable distance.

So not forever but a very long time indeed.  Human gift givers need not worry.

An international team of astronomers has discovered the farthest and largest body of water in the universe.

The distant quasar is one of the most powerful known objects in the universe and has an energy output of 1,000 trillion suns -- about 65,000 times that of the Milky Way galaxy. The quasar's power comes from matter spiraling into the central supermassive black hole, estimated at some 20 billion times the mass of our sun, said study leader Matt Bradford of Caltech and NASA's Jet Propulsion Laboratory in Pasadena, Calif.

Because the quasar -- essentially a voraciously feeding black hole -- is so far away, its light has taken 12 billion light years to arrive at Earth. Since one light year equals about 6 trillion miles, the observations reveal a time when the universe was very young, perhaps only 1.6 billion years old. Astronomers believe the universe was formed by the Big Bang roughly 13.6 billion years ago.

The water measured in the quasar is in the form of vapor and is the largest mass of water ever found, according to the researchers. The amount of water estimated to be in the quasar is at least 100,000 times the mass of the sun, equivalent to 34 billion times the mass of the Earth.

Fool's gold (pyrite) has a metallic luster similar to that of gold and is helping scientists understand the evolution of the Earth.
Studying the composition of pyrite enables a geological snapshot of events at the time when it was formed.

Studying the composition of different forms of iron in fool’s gold gives scientists clues as to how conditions such as atmospheric oxygen influenced the processes forming the compound.

The latest research shows that bacteria - which would have been an abundant life form at the time - did not influence the early composition of pyrite.

This result, which contrasts with previous thinking, gives scientists a much clearer picture of the process.

One more in a growing list of particles is added with the discovery of a heavy relative of the neutron.
The neutral Xi-sub-b is the latest entry in the periodic table of baryons. Baryons are particles formed of three quarks, the most common examples being the proton (two up quarks and a down quark) and the neutron (two down quarks and an up quark). The neutral Xi-sub-b belongs to the family of bottom baryons, which are about six times heavier than the proton and neutron because they all contain a heavy bottom quark. The particles are produced only in high-energy collisions, and are rare and very difficult to observe.

Other Worthy Stories of the Week
Experimental archeologists test past by making it real
How online companies get you to share more and to spend more
Aura satellite measures pollution from African fires
Mysterious fossils provide new clues to insect evolution
Deep below the Deepwater Horizon spill
Oldest known Eucalyptus fossils found in South America
Closeup image of asteroid Vesta
Rising ocean levels: Too late to turn the tide?
Asexual ants are actually having sex
Water fountain shows cool physics
Elliptical galaxies much younger than once thought
Smartphone viewing making your eyes tired?
Nanotechnology for water filter

For even more science news:
General Science Collectors:
Alpha-Galileo
BBC News Science and Environment
Eureka Science News
LiveScience
New Scientist
PhysOrg.com
SciDev.net
Science/AAAS
Science Alert
Science Centric
Science Daily
Scientific American
Space Daily

Blogs:
A Few Things Ill Considered Techie and Science News
Cantauri Dreams space exploration
Coctail Party Physics Physics with a twist.
Deep Sea News marine biology
Laelaps more vertebrate paleontology
List of Geoscience Blogs
ScienceBlogs
Space Review
Techonology Review
Tetrapod Zoologyvertebrate paleontology
Science Insider
Scientific Blogging.
Space.com
Wired News
Science RSS Feed: Medworm
The Skeptics Guide to the Universe--a combination of hard science and debunking crap

At Daily Kos:
This Week in Science by DarkSyde
Overnight News Digest:Science Saturday by Neon Vincent. OND tech Thursday by rfall.
Pique the Geek by Translator Sunday evenings about 9 Eastern time
All diaries with the DK GreenRoots Tag.
All diaries with the eKos Tag
A More Ancient World by matching mole
Astro Kos
SciTech at Dkos.
Sunday Science Videos by palantir

NASA picture of the day. For more see the NASA image gallery or the Astronomy Picture of the Day Archive.

Omega Nebula, NASA, Public Domain

Extended (Optional)

Originally posted to possum on Mon Jul 25, 2011 at 12:42 PM PDT.

Also republished by Pink Clubhouse, lundi channel, Progressive Friends of the Library Newsletter, and SciTech.

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