Frozen Frogs Don't Croak
"Freeze-tolerant" amphibians hold promise for organ transplant technology
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The North American wood frog survives the winter with a heart-stopping strategy. This frog, found from southern Ohio up to the Arctic Circle, puzzles researchers with its ability to literally "freeze and thaw" along with normal winter-spring weather patterns. To survive winter's freezing temperatures, the frog doesn't fight the temperatures; it just freezes from the outside-in.
At the first sign of ice in late fall or early winter, the frog freezes solid as a rock.
"That touch of ice immediately sets off signals inside the frog that pulls water away from the center of its body, so the frog's internal organs are now wrapped in a puddle of water that then turns to solid ice," says Constanzo, a scientist who has been studying them for years now.
The frog's heart stops beating, its kidneys stop functioning and its respiration ceases - for months. The frogs endure this suspended animation by producing a type of antifreeze made with glucose, keeping the water in their cells in a liquid state at temperatures below 32 degrees Fahrenheit (0 degrees Celsius).
When warmer spring temperatures trigger the frog to thaw, its heart and brain thaw first, followed by its body, all in perfect synchrony. Costanzo refers to this series of events as "a spontaneous resumption of function." Within 10 hours, the frog is fully functional.
Costanzo and others are studying this amazing phenomenon in hopes of discovering new technology to preserve human organs that are destined for transplantation.
"Currently it's not possible to freeze human organs for transplantation," said Costanzo, "yet the wood frog and several other amphibians and reptiles have solved not only the problem of freezing individual tissues and organs, but also that of simultaneously freezing all organ systems."
According to the Scientific Registry of Transplant Recipients, more than 85,000 patients were on the national waiting list for an organ transplant as of June 2004. At present, a heart can be persevered for only five hours before it must be implanted into a recipient; a kidney might last 72 hours. If organs could be preserved longer, more time would be available for both the recipient and the associated surgical team, leading to improved transplantation success rates.
The History of Scotch Tape
Scotch tape was invented in 1930 by banjo playing 3M engineer Richard Drew. Scotch tape was the world's first transparent cellophane adhesive tape. Richard Drew also invented the first masking tape in 1925, a two-inch-wide tan paper tape with a pressure sensitive adhesive backing.
In 1923, Richard Drew joined the 3M company located in St. Paul, Minnesota. At the time, 3M only made sandpaper. Drew was product testing 3M's Wetordry brand sandpaper at a local auto bodyshop, when he noticed that auto painters were having a hard time making clean dividing lines on two-color paint jobs. Richard Drew was inspired to invent the world's first masking tape in 1925, as a solution to the auto painters' dilemma.
The brandname Scotch came about while Richard Drew was testing his first masking tape to determine how much adhesive he needed to add. The bodyshop painter became frustrated with the sample masking tape and exclaimed, "Take this tape back to those Scotch bosses of yours and tell them to put more adhesive on it!" The name was soon applied to the entire line of 3M tapes.
Scotch Brand Cellulose Tape was invented five years later. Made with a nearly invisible adhesive, the waterproof transparent tape was made from: oils, resins, and rubber; and had a coated cellophane backing.
According to 3M
Richard Drew, a young 3M engineer, invented the first waterproof, see-through, pressure-sensitive tape, thus supplying an attractive, moisture-proof way to seal cellophane food wrap for bakers, grocers, and meat packers. Drew sent a trial shipment of the new Scotch cellulose tape to a Chicago firm specializing in printing cellophane for bakery products. The response was put this product on the market! Shortly after, heat sealing for cellophane reduced the original use of the new tape. However, Americans in a depressed economy discovered they could use the tape to mend a wide variety of things like torn pages of books and documents, broken toys, ripped window shades, even dilapidated currency.
John A. Borden, another 3M engineer invented the first tape dispenser with a built-in cutter blade in 1932. Scotch (TM) Brand Magic (TM) Transparent Tape was invented in 1961, an almost invisible tape that never discolored and could be written on.
The History of the Guillotine
During the 1700's, executions in France were public events where entire towns gathered to watch. A common execution method for a poor criminal was quartering, where the prisoner's limbs were tied to four oxen, then the animals were driven in four different directions ripping the person apart. Upper-class criminals could buy their way into a less painful death by hanging or beheading.
A guillotine is an instrument for inflicting capital punishment by decapitation that came into common use in France after 1792 (during the French Revolution). In 1789, Dr. Joseph-Ignace Guillotin first suggested that all criminals should be executed by decapitation - by means of a “machine that beheads painlessly”. A decapitation machine called the Guillotine was built and used during the French Revolution. Joseph Guillotin was born in Saintes, France in 1738 and elected to the French National Assembly in 1789.
Doctor Joseph Ignace Guillotin 1738-1814
Doctor Joseph Ignace Guillotin belonged to a small political reform movement that wanted to banish the death penalty completely. Guillotin argued for a painless and private capital punishment method equal for all the classes, as an interim step towards completely banning the death penalty.
Beheading devices had already been used in Germany, Italy, Scotland and Persia for aristocratic criminals. However, never had such a device been adopted on a large institutional scale. The French named the guillotin after Doctor Guillotin. The extra 'e' at the end of the word was added by an unknown English poet who found guillotine easier to rhythm with.
Doctor Guillotin together with German engineer and harpsichord maker Tobias Schmidt, built the prototype for an ideal guillotine machine. Schmidt suggested using a diagonal blade instead of a round blade.
The Last Guillotine Execution
On September 10, 1977, the last execution by guillotine took place in Marseilles, France, when the murderer Hamida Djandoubi was beheaded.
Guillotine Facts
Total weight of a guillotine is about 1278 lbs
The guillotine metal blade weighs about 88.2 lbs
The height of guillotine posts average about 14 feet
The falling blade has a rate of speed of about 21 feet/second
Just the actual beheading takes 2/100 of a second
The time for the guillotine blade to fall down to where it stops takes 70th of a second
True or False? When Memories Play Tricks
The ease with which people's memories can be distorted is disconcerting.
Forgetting is a common, if bothersome, behavior of the human memory system. The benign loss of information is usually forgiven. Memory that is not lost but is instead distorted may not be so benign.
For example, one may have a memory of an important event such as a wedding day, the birth of a child or even a traumatic event such as September 11, 2001. However, such memories are likely distorted to some degree. These distortions, or false memories, manifest themselves in various forms, from changes in the source of a memory (for example, believing that a piece of news came from a television program rather than from a friend) to changes in the content of the memory itself (for example, believing a criminal carried a gun rather than a knife).
False memories are created in various ways. In the "misinformation effect," people who see one version of an incident and then are presented with a second version will often recollect the altered version as correct. For example, if witnesses to a crime are later given a description in which key details of the crime are altered - for example, a car stops at a stop sign in one version and a yield sign in the other - they often remember having originally seen the altered event.
The misinformation effect may arise in a criminal investigation if repeated questioning inadvertently suggests a certain outcome or contains misinformation. Further, research has shown that people can easily integrate memories from multiple events into what they believe is a memory for a single event.
With NSF support, Stark and Yoko Okado from Johns Hopkins used functional magnetic resonance imaging (fMRI) to understand how this misinformation effect works… The researchers collected fMRI data to examine the activity in brain regions associated with memory processing. One such region is the left hippocampus, a seahorse-shaped structure deep within the brain essential for establishing new memories of events.
This study highlights the critical role of neural activity in particular brain regions during an event for determining whether a memory will be accurate or susceptible to distortion. Scientists can then improve their understanding of how memory distortions occur, with implications for situations ranging from eyewitness testimony to recovered repressed memories to the simple distortions that occur in our everyday lives.
http://www.nsf.gov/discoveries/disc_summ.jsp?cntn_id=100658&org=NSF
Were They Really Killed by a Meteorite?
A meteorite impact 65 million years ago is the simple explanation for the extinction of the dinosaurs. The exact details are much more complex, and researchers are still trying to nail down exactly what happened. The Cretaceous-Tertiary (K-T) extinction event is like an ancient tapestry that has become matted and soiled due to time and neglect. There are hundreds of threads of evidence that need to be untangled, smoothed out, and put in their proper place before a clear picture can emerge.
The first, most important thread of evidence is a strip of clay that runs through rocks around the world. Known as the K-T boundary layer, this is the line no dinosaur could cross (although their relatives, the birds, did survive).
In 1980, a team of researchers led by Luis Alvarez and his son, Walter, discovered that the boundary layer contains a relatively high concentration of iridium. Iridium is rare on the Earth's surface but is often found in meteorites. During the molten phase of our planet's formation, most of the iridium of Earth traveled down with iron to form the planetary core. The Earth does receive a light surface dusting of iridium from the occasional meteorites, and some volcanoes can release iridium if their lava comes from a deep enough source. These events give the planet's surface a background iridium level of 0.02 parts per billion (ppb) or less.
Depending on the location of the rocks, the K-T boundary layer has varying amounts of iridium, but all are far above that background level. The section analyzed by Alvarez had 9 ppb. Other sections have upwards of a million times the background level. Luis and Walter Alvarez surmised that a large meteorite rich in iridium must have hit the Earth, and the after-effects of the impact led to the demise of the dinosaurs. The meteorite […] smashed open a vast cavern 40 kilometers deep and 100 kilometers across. The energy released by this impact was equal to 100 million megatons of TNT. The atomic bomb that exploded over Hiroshima released energy equivalent to about 10 kilotons of TNT (or 0.01 megatons).
http://www.wordiq.com/definition/K-T_boundary#Impact_event_and_iridium
Frozen Frogs Don't Croak
amphibian |
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to thaw |
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frigid |
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to cease |
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suspended animation |
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antifreeze |
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to trigger (sb/sth to do sth) |
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resumption |
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improved success rates |
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2. The History of Scotch Tape
adhesive |
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cellophane |
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cutter blade |
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dilapidated |
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dilemma |
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dispenser |
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moisture-proof |
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pressure-sensitive |
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resin |
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sandpaper |
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Scotch tape |
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see-through |
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to discolor |
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to seal (heat sealing) |
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transparent |
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waterproof |
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3. The History of the Guillotine
decapitation |
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diagonal blade |
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exile |
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guillotine |
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harpsichord |
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interim |
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limbs |
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quartering |
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to behead |
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to inflict capital punishment |
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to rip sb apart |
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to send sb into exile |
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to severe |
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4. True or False? When Memories Play Tricks
altered |
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benign |
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disconcerting |
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functional magnetic resonance imaging (fMRI) |
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hippocampus |
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implications |
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inadvertently |
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memory processing |
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repressed memories |
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seahorse-shaped structure |
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susceptible to |
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to distort |
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to recollect |
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yield sign |
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5. Were They Really Killed by a Meteorite?
cavern |
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clay |
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concentration |
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Cretaceous-Tertiary (K-T) border |
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demise |
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extinction |
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iridium |
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metorite impact |
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parts per billion |
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planetary core |
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tapestry |
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the K-T boundary layer |
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the molten phase |
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to nail down |
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to surmise |
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