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Sunday, October 10, 2010

See the Future with a Search A Web startup demos a "predictive" search engine.


A startup called Recorded Future has developed a tool that scrapes real-time data from the Internet to find hints of what will happen in the future. The company's search tool spits out results on a timeline that stretches into the future as well as the past.
Eye candy: This visualization shows the connections between different places, companies, and people, following a search using Recorded Future.
Credit: Recorded Future

The 18-month-old company gained attention earlier this year after receiving money from the venture capital arms of both Google and the CIA. Now the company has offered a glimpse of how its technology works.

Conventional search engines like Google use links to rank and connect different Web pages. Recorded Future's software goes a level deeper by analyzing the content of pages to track the "invisible" connections between people, places, and events described online.

"That makes it possible for me to look for specific patterns, like product releases expected from Apple in the near future, or to identify when a company plans to invest or expand into India," says Christopher Ahlberg, founder of the Boston-based firm.

A search for information about drug company Merck, for example, generates a timeline showing not only recent news on earnings but also when various drug trials registered with the website clinicaltrials.gov will end in coming years. Another search revealed when various news outlets predict that Facebook will make its initial public offering.

That is done using a constantly updated index of what Ahlberg calls "streaming data," including news articles, filings with government regulators, Twitter updates, and transcripts from earnings calls or political and economic speeches. Recorded Future uses linguistic algorithms to identify specific types of events, such as product releases, mergers, or natural disasters, the date when those events will happen, and related entities such as people, companies, and countries. The tool can also track the sentiment of news coverage about companies, classifying it as either good or bad.

Recorded Future's customer base is currently "sub-100," says Ahlberg. It includes a mix of financial firms, government analysts, and media analysts, who pay a monthly fee to access the online tools. "Government analysts are interested in tracking people and places, while financial services may want to reveal events coming up around particular companies," says Ahlberg.

As well as providing a slick online interface to perform searches that spit out timelines showing the results (see video), Recorded Future offers free e-mail newsletters that tip users off to predictions in specific areas. It also makes it possible for customers to write software that draws on the tool's data and analysis through application programming interfaces, or APIS.

In time, this may lead to the development of apps targeted at consumers, says Ahlberg. "If I'm about to buy an iPhone, I might want to know if I am going to look stupid because they'll launch a new one next week, or how long it usually takes for competitors to launch competing products after a new Apple launch." Financial analysts are already using the company's APIs to overlay or even integrate Recorded Future's data into their own models, he says.
Future gazing: A Recorded Future timeline shows the dates of future product launches, as well as previous releases.
Credit: Recorded Future

"We have proven out that our data can make strong predictions," says Ahlberg, citing studies that compared Recorded Future's output with changes in the volume of activity around particular financial stocks. "We found that our momentum metric, which indicates the strength of activity around an event or entity, and our future events correlate with the volume of market activity," says Ahlberg.

His company's tools can also be used to work out which sources of information give the best clues as to future events. A recent analysis showed that the posts on one of the Financial Times's blogs were better than other news sources at predicting the performance of companies on the S&P 500 share index. Negative posts about a company correlated with below-market performance a week later, while positive ones correlated with above-market performance.

"What they're really doing here is identifying and collating statements that have been made about the future," says Steven Skiena at the State University of New York at Stony Brook. Skiena developed similar technology used by another startup, General Sentiment, to mine material from news and blogs. "An analyst can use those to inform their own predictions, less risky than Recorded Future actually making predictions themselves."

Various tools are capable of extracting events, people, and companies from text, but aligning that information in time is a trickier task, says Panagiotis Ipeirotis, at New York University's Leonard Stern School of Business. Ipeirotis researches how economically important data can be mined from online news sources and social media. "Analysis of sequences of events is very interesting, and underexploited in the research literature," he says. "Even getting decently timed data of news articles in order to properly generate event sequences is a hard problem."

This focus on the timeline sets Recorded Future apart from other firms trying to gain insights by mining news and other data, says Ipeirotis. "I'm curious to see when other text analytics firms will jump into the trend."

Recorded Future is about to expand its service to cover Arabic and Chinese sources. Making its indexes bigger is a major priority. "I'd like to be able to get in front of every piece of streaming data on the planet," says Ahlberg.

As the databases covered by Recorded Future, General Sentiment, and others grow, more powerful types of analysis will become possible, says Skiena. "I'm currently working with social scientists on models to predict what the probability is that a person that gets few mentions today suddenly becomes very famous in the future, by looking back at years of past data," he says.

Saturday, October 9, 2010

Men Perspire, Women Glow: Men Are More Efficient at Sweating, Study Finds


Women have to work harder than men in order to start sweating, while men are more effective sweaters during exercise, according to new research published in the journal Experimental Physiology.
New research shows that women have to work harder than men in order to start sweating, while men are more effective sweaters during exercise. (Credit: iStockphoto/Steve Cole)

The study by Japanese scientists at Osaka International University and Kobe University looked at differences between men and women's sweating response to changes in exercise intensity. The researchers asked four groups of subjects (trained and untrained females, trained and untrained males) to cycle continuously for an hour in a controlled climate with increasing intensity intervals.

The results showed that men are more efficient at sweating. While exercise training improves sweating in both sexes, the degree of improvement is greater in men, with the difference becoming even more pronounced as the level of exercise intensity increases. The untrained females had the worst sweating response of all requiring a higher body temperature than the other groups (or work intensity) to begin sweating. In other words, women need to get hotter than men before they get sweaty.

The study's coordinator Yoshimitsu Inoue commented: 'It appears that women are at a disadvantage when they need to sweat a lot during exercise, especially in hot conditions.'

Previous studies have demonstrated that men have a higher sweat output than women, in part because testosterone is believed to enhance the sweating response. Physical training is known to decrease the body's core temperature threshold for the activation of the sweating response, which works to the athlete's advantage and allows them to perform longer. This is the first study, however, to investigate the sex differences in the effects of physical training on the sweating response during exercise.

The findings have implications for exercise and heat tolerance in humans, including shedding light on why the sexes cope differently with extremes of temperature like heat waves.

Inoue believes there may be an evolutionary reason why men and women have evolved to sweat differently. 'Women generally have less body fluid than men and may become dehydrated more easily,' he explains. 'Therefore the lower sweat loss in women may be an adaptation strategy that attaches importance to survival in a hot environment, while the higher sweat rate in men may be a strategy for greater efficiency of action or labour.'

Inoue says future studies will look more closely at the relationship between reproductive hormones and the sweating response as well as the effectiveness of different kinds of sweat (sweat that evaporates and cools versus sweat that drops off).

In the meantime, Inoue advises women should take more care than men in hot conditions. But he adds, 'Both men and women can acclimate themselves better to heat if they exercise regularly before a heat wave comes.'

Editor's Note: This article is not intended to provide medical advice, diagnosis or treatment.

Living Dinosaurs in Space: Galaxies in Today's Universe Thought to Have Existed Only in Distant Past


Using Australian telescopes, Swinburne University astronomy student Andy Green has found 'living dinosaurs' in space: galaxies in today's Universe that were thought to have existed only in the distant past.
A simulation of a star forming galaxy similar to those observed. Cold gas (red) flowing onto a spiral galaxy feeds star formation. (Credit: Rob Crain, James Geach, the Virgo Consortium, Andy Green & Swinburne Astronomy Productions)

The report of his finding -- Green's first scientific paper -- appears on the cover of the Oct. 7 issue of Nature.

"We didn't think these galaxies existed. We've found they do, but they are extremely rare," said Professor Karl Glazebrook, Green's thesis supervisor and team leader.

The Swinburne researchers have likened the galaxies to the 'living dinosaurs' or Wollemi Pines of space -- galaxies you just wouldn't expect to find in today's world.

"Their existence has changed our ideas about how star formation is fuelled and understanding star formation is important. Just look at the Big Bang, which is how we all got here," Glazebrook said.

The galaxies in question look like disks, reminiscent of our own galaxy, but unlike the Milky Way they are physically turbulent and are forming many young stars.

"Such galaxies were thought to exist only in the distant past, ten billion years ago, when the Universe was less than half its present age," Glazebrook said.

"Stars form from gas, and astronomers had proposed that the extremely fast star formation in those ancient galaxies was fuelled by a special mechanism that could exist only in the early Universe -- cold streams of gas continually falling in."

But finding the same kind of galaxy in today's Universe means that that mechanism can't be the only way such rapid star formation is fuelled. Instead it seems that when young stars form, they create turbulence in their surrounding gas. The more stars are forming in a galaxy, the more turbulence it has.

"Turbulence affects how fast stars form, so we're seeing stars regulating their own formation," Green said.

"It's a bit like a little girl deciding how many siblings she should have." "We still don't know where the gas to make these stars comes from though," he said.

Understanding star formation is one of the most basic, unsolved problems of astronomy. Another significant aspect of the paper is that it was authored by a PhD student.

As Glazebrook pointed out, being first author of a Nature paper as a student is as rare as the galaxies they've discovered. This is an achievement not lost on the young scientist.

"Nature is one of the most prestigious journals in science. It was a pleasant surprise for our work to receive this kind of accolade," Green said.

The study was based on selected galaxies from the Sloan Digital Sky Survey, a kind of census of modern galaxies.

"We studied extreme galaxies to compare them with the ancient Universe," Green said.

He observed them using the Anglo-Australian Telescope (AAT) and the Australian National University's 2.3 metre telescope, both located at Siding Spring Observatory in New South Wales. Professor Matthew Colless, Director of the Australian Astronomical Observatory, which operates the AAT, said that the study highlighted the value of the instruments found at Australia's telescopes.

"They are ideal for studying in detail the nearby counterparts of galaxies seen in the distant Universe by the eight and 10 metre telescopes," he said.

For the next stage of his research, Green plans to use one of these 10 metre telescopes -- in fact the largest optical telescope in the world at the Keck Observatory -- to take an even closer look at the rare galaxies he has discovered.

Green admitted: "Really, we need a bigger telescope, the Giant Magellan Telescope, to understand star formation. But, until it's constructed, Keck is the best tool available."

Green's access to the Keck will be possible thanks to Swinburne's agreement with Caltech, which gives the Swinburne astronomers access to the Keck Observatory in Hawaii for up to 20 nights per year.

Too Much of a Good Thing: Human Activities Overload Ecosystems With Nitrogen


Humans are overloading ecosystems with nitrogen through the burning of fossil fuels and an increase in nitrogen-producing industrial and agricultural activities, according to a new study. While nitrogen is an element that is essential to life, it is an environmental scourge at high levels.
At Lake Atitlan in Guatemala, excess nitrogen promotes algae growth, which leads to eutrophication. Over-nourished by excess nutrients including nitrogen, which drains from nearby farms, swirls of blue-free algae form. The eventual decay of the algae robs the water of oxygen, and thereby creates a dead zone where other plants and animals cannot survive. (Credit: NASA Earth Observatory image by Jesse Allen, based on data from the NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team)

According to the study, excess nitrogen that is contributed by human activities pollutes fresh waters and coastal zones, and may contribute to climate change. Nevertheless, such ecological damage could be reduced by the adoption of time-honored sustainable practices.

Appearing in the October 8, 2010 edition of Science and conducted by an international team of researchers, the study was partially funded by the National Science Foundation.

The Nitrogen Cycle

The nitrogen cycle--which has existed for billions of years--transforms non-biologically useful forms of nitrogen found in the atmosphere into various biologically useful forms of nitrogen that are needed by living things to create proteins, DNA and RNA, and by plants to grow and photosynthesize. The transformation of biologically useful forms of nitrogen to useful forms of nitrogen is known as nitrogen fixation.

Mostly mediated by bacteria that live in legume plant roots and soils, nitrogen fixation and other components of the nitrogen cycle weave and wind through the atmosphere, plants, subsurface plant roots, and soils; the nitrogen cycle involves many natural feedback relationships between plants and microorganisms.

According to the Science paper, since pre-biotic times, the nitrogen cycle has gone through several major phases. The cycle was initially controlled by slow volcanic processes and lightning and then by anaerobic organisms as biological activity started. By about 2.5 billion years ago, as molecular oxygen appeared on Earth, a linked suite of microbial processes evolved to form the modern nitrogen cycle.

Human Impacts on the Nitrogen Cycle

But the start of the 20th century, human contributions to the nitrogen cycle began skyrocketing. "In fact, no phenomenon has probably impacted the nitrogen cycle more than human inputs of nitrogen into the cycle in the last 2.5 billion years," says Paul Falkowski of Rutgers University, a member of the research team.

"Altogether, human activities currently contribute twice as much terrestrial nitrogen fixation as natural sources, and provide around 45 percent of the total biological useful nitrogen produced annually on Earth," says Falkowski. Much of the human contributions of nitrogen into ecosystems come from an 800 percent increase in the use of nitrogen fertilizers from 1960 to 2000.

Another problem: Much of nitrogen fertilizer that is used worldwide is applied inefficiently. As a result, about 60 percent of the nitrogen contained in applied fertilizer is never incorporated into plants and so is free to wash out of root zones, and then pollute rivers, lakes, aquifers and coastal areas through eutrophication. (Eutrophication is a process caused by excess nutrients that depletes oxygen in water bodies and ultimately leads to the death of animal life.)

In addition, some reactions involving nitrogen release nitrogen oxide into the atmosphere. Nitrogen oxide is a greenhouse gas that has 300 times (per molecule) the warming potential of carbon dioxide. In addition, nitrogen oxide destroys stratospheric ozone, which protects the earth from harmful ultraviolet (UV-B) radiation.

Methods to Reduce Nitrogen Overloading

"Natural feedbacks driven by microorganisms will likely produce a new steady-state over time scales of many decades," says Falkowski. "Through this steady state, excess nitrogen added from human sources will be removed at rates equivalent to rates of addition, without accumulating."

But meanwhile, the Earth's population is approaching 7 billion people, and so ongoing pressures for food production are continuing to increase. "There is no way to feed people without fixing huge amounts of nitrogen from the atmosphere, and that nitrogen is presently applied to crop plants very ineffectively." says Falkowski.

So unless promising interventions are taken, the damage done by humans to the Earth's nitrogen cycle will persist for decades or centuries. These promising interventions, which would be designed to reduce the need to use fertilizers that add nitrogen to ecological systems, could include:

* Using systematic crop rotations that would supply nitrogen that would otherwise be provided by fertilizers;

* Optimizing the timing and amounts of fertilizer applications, adopting selected breeding techniques or developing genetically engineered varieties of plants that would increase the efficiency of nitrogen use;

* Using traditional breeding techniques to boost the ability of economically important varieties of wheat, barley and rye to interact favorably with the microbial communities associated with plant root systems and do so in ways that enhance the efficiency of nitrogen use.

"While the processes of eutrophication have been recognized for many years, only recently have scientists been able to begin placing the anthropogenic processes in the context of an understanding of the broader biogeochemical cycles of the planet," says Robert Burnap, an NSF program director. This is an important article because it concisely develops this understanding and also provides reasonable predictions regarding the economic and policy dimensions of the problem."

Hubble Astronomers Uncover an Overheated Early Universe


If you think global warming is bad, 11 billion years ago the entire universe underwent, well, universal warming.
This diagram traces the evolution of the 
universe from the big bang to the present. 
Two watershed epochs are shown. Not long
after the big bang, light from the first stars 
burned off a fog of cold hydrogen in a 
process called reionization. At a later 
epoch quasars, the black-hole-powered 
cores of active galaxies, pumped out 
enough ultraviolet light to reionize 
the primordial helium. (Credit: NASA
ESA, and A. Feild (STScI))

The consequence was that fierce blasts of radiation from voracious black holes stunted the growth of some small galaxies for a stretch of 500 million years.

This is the conclusion of a team of astronomers who used the new capabilities of NASA's Hubble Space Telescope to probe the invisible, remote universe.

Using the newly installed Cosmic Origins Spectrograph (COS) they have identified an era, from 11.7 to 11.3 billion years ago, when the universe stripped electrons off from primeval helium atoms -- a process called ionization. This process heated intergalactic gas and inhibited it from gravitationally collapsing to form new generations of stars in some small galaxies. The lowest-mass galaxies were not even able to hold onto their gas, and it escaped back into intergalactic space.

Michael Shull of the University of Colorado and his team were able to find the telltale helium spectral absorption lines in the ultraviolet light from a quasar -- the brilliant core of an active galaxy. The quasar beacon shines light through intervening clouds of otherwise invisible gas, like a headlight shining through a fog. The beam allows for a core-sample probe of the clouds of gas interspersed between galaxies in the early universe.

The universe went through an initial heat wave over 13 billion years ago when energy from early massive stars ionized cold interstellar hydrogen from the big bang. This epoch is actually called reionization because the hydrogen nuclei were originally in an ionized state shortly after the big bang.

But Hubble found that it would take another 2 billion years before the universe produced sources of ultraviolet radiation with enough energy to do the heavy lifting and reionize the primordial helium that was also cooked up in the big bang.

This radiation didn't come from stars, but rather from quasars. In fact the epoch when the helium was being reionized corresponds to a transitory time in the universe's history when quasars were most abundant.

The universe was a rambunctious place back then. Galaxies frequently collided, and this engorged supermassive black holes in the cores of galaxies with infalling gas. The black holes furiously converted some of the gravitational energy of this mass to powerful far-ultraviolet radiation that would blaze out of galaxies. This heated the intergalactic helium from 18,000 degrees Fahrenheit to nearly 40,000 degrees. After the helium was reionized in the universe, intergalactic gas again cooled down and dwarf galaxies could resume normal assembly. "I imagine quite a few more dwarf galaxies may have formed if helium reionization had not taken place," said Shull.

So far Shull and his team only have one sightline to measure the helium transition, but the COS science team plans to use Hubble to look in other directions to see if the helium reionization uniformly took place across the universe.

The science team's results will be published in the October 20 issue of The Astrophysical Journal.

Friday, October 8, 2010

From Eye to Brain: Researchers Map Functional Connections Between Retinal Neurons at Single-Cell Resolution


By comparing a clearly defined visual input with the electrical output of the retina, researchers at the Salk Institute for Biological Studies were able to trace for the first time the neuronal circuitry that connects individual photoreceptors with retinal ganglion cells, the neurons that carry visuals signals from the eye to the brain.
A unique neural recording system developed by an 
international team of high energy physicists, which 
is able to record simultaneously the tiny electrical 
signals generated by hundreds of the retinal output 
neurons, is one of the essential elements of the study. 
Recording electrodes are shown in the foreground 
and retinal ganglion cells in the background. 
(Credit: Image: Courtesy of Dr. E.J. Chichilnisky, 
Salk Institute for Biological Studies)

Their measurements, published in the Oct. 7, 2010, issue of the journal Nature, not only reveal computations in a neural circuit at the elementary resolution of individual neurons but also shed light on the neural code used by the retina to relay color information to the brain.

"Nobody has ever seen the entire input-output transformation performed by complete circuits in the retina at single-cell resolution," says senior author E.J. Chichilnisky, Ph.D., an associate professor in the Systems Neurobiology Laboratories. "We think these data will allow us to more deeply understand neuronal computations in the visual system and ultimately may help us construct better retinal implants."

One of the essential elements that made the experiments possible was the unique neural recording system developed by an international team of high-energy physicists from the University of California, Santa Cruz; the AGH University of Science and Technology, Krakow, Poland; and the University of Glasgow, UK. This system is able to record simultaneously the tiny electrical signals generated by hundreds of the retinal output neurons that transmit information about the outside visual world to the brain. These recordings are made at high-speed (over ten million samples each second) and with fine spatial detail, sufficient to detect even a locally complete population of the tiny and densely spaced output cells known as "midget" retinal ganglion cells.

Retinal ganglion cells are classified based on their size, the connections they form, and their responses to visual stimulation, which can vary widely. Despite their differences, they all have one thing in common-a long axon that extends into the brain and forms part of the optic nerve.

Visual processing begins when photons entering the eye strike one or more of the 125 million light-sensitive nerve cells in the retina. This first layer of cells, which are known as rods and cones, converts the information into electrical signals and sends them to an intermediate layer, which in turn relays signals to the 20 or so distinct types of retinal ganglion cells.

In an earlier study, Chichilnisky and his team found that each type of retinal ganglion cells forms a seamless lattice covering visual space that transmits a complete visual image to the brain. In the current study, postdoctoral researcher and co-first author Greg D. Field, Ph.D., and his collaborators zoomed in on the pattern of connectivity between these layers of retinal ganglion cells and the full lattice of cone receptors.

The Salk researchers simultaneously recorded hundreds of retinal ganglion cells, and based on density and light response properties, identified five cell types: ON and OFF midget cells, ON and OFF parasol cells, and small bistratified cells, which collectively account for approximately 75 percent of all retinal ganglion cells.

To resolve the fine structure of receptive fields-the small, irregularly shaped windows through which neurons in retina view the world-the authors used stimuli with tenfold smaller pixels. "Instead of a diffuse region of light sensitivity, we detected punctate islands of light sensitivity separated by regions of no light sensitivity," he says.

When combined with information on spectral sensitivities of individual cones, maps of these punctate islands not only allowed the researchers to recreate the full cone mosaic found in the retina, but also to conclude which cone fed information to which retinal ganglion cell.

"Just by stimulating input cells and taking a high density recording from output cells, we can identify all individual input and output cells and find out who is connected to whom," says Chichilnisky.

Chichilnisky and his team discovered that populations of ON and OFF midget and parasol cells each sampled the complete population of cones sensitive to red or green light, with midget cells sampling these cones in a surprisingly non-random fashion. Only OFF midget cells frequently received strong input from cones sensitive to blue light.

The research was funded in part by the Helen Hay Whitney Foundation, the German Research Foundation, the National Institutes of Health, the Chapman Foundation, the Miller Institute for Basic Research in Science, the Polish Ministry of Science and Higher Education, the Burroughs Wellcome Trust, the McKnight Foundation, the National Science Foundation, the Sloan Foundation, the Engineering and Physical Sciences Research Council and The Royal Society of Edinburgh.

Researchers who also contributed to the work include co-first author Jeffrey L. Gauthier, Ph.D., Martin Greschner, Timothy A. Machado, Lauren H. Jepson, and Jonathon Shlens in the Systems Neurobiology Laboratory at the Salk Institute, co-first author Alexander Sher and Alan Litke at the Santa Cruz Institute for Particle Physics at the University of California, Santa Cruz, Deborah E. Gunning and Keith Mathieson in the Department of Physics and Astronomy at the University of Glasgow, Wladyslaw Dabrowski at the Faculty of Physics and Applied Computer Science at the AGH University of Science and Technology in Krakow, and Liam Paninski in the Department of Statistics and Center for Theoretical Neuroscience at Columbia University, New York.

Editor's Note: This article is not intended to provide medical advice, diagnosis or treatment.

Thursday, October 7, 2010

2010 Nobel Prize in Chemistry: Creating Complex Carbon-Based Molecules Using Palladium


The Royal Swedish Academy of Sciences has awarded the Nobel Prize in Chemistry for 2010 to Richard F. Heck, Ei-ichi Negishi and Akira Suzuki for developing new ways of linking carbon atoms together that has allowed scientists to make medicines and better electronics.
New ways of linking carbon atoms together has allowed scientists to make medicines and better electronics. (Credit: iStockphoto/Liang Zhang)

American citizen Richard F. Heck, 79, of the University of Delaware in Newark, Delaware, Japanese citizens Akira Suzuki, 80, of Hokkaido University in Sapporo, Japan, and Ei-Ichi Negishi, 75, of Purdue University in West Lafayette, Indiana, will share the 10 million Swedish crowns ($1.5 million) award for their development of "palladium-catalyzed cross couplings in organic systems."

Carbon, the atom that is the backbone of molecules in living organisms, is usually very stable and it can be difficult in the laboratory chemically to synthesize large molecules containing carbon. In the Heck reaction, Negishi reaction and Suzuki reaction, carbon atoms meet on a palladium atom, which acts as a catalyst. The carbon atoms attach to the palladium atom and are thus positioned close enough to each other for chemical reactions to start. This allows chemists to synthesize large, complex carbon-containing molecules.

The Academy said it's a "precise and efficient" tool that is used by researchers worldwide, "as well as in the commercial production of for example pharmaceuticals and molecules used in the electronics industry."

Great art in a test tube

Organic chemistry has developed into an art form where scientists produce marvelous chemical creations in their test tubes. Humankind benefits from this in the form of medicines, ever-more precise electronics and advanced technological materials. The Nobel Prize in Chemistry 2010 awards one of the most sophisticated tools available to chemists today.

This year's Nobel Prize in Chemistry is awarded to Richard F. Heck, Ei-ichi Negishi and Akira Suzuki for the development of palladium-catalyzed cross coupling. This chemical tool has vastly improved the possibilities for chemists to create sophisticated chemicals -- for example, carbon-based molecules as complex as those created by nature itself.

Carbon-based (organic) chemistry is the basis of life and is responsible for numerous fascinating natural phenomena: colour in flowers, snake poison and bacteria killing substances such as penicillin. Organic chemistry has allowed man to build on nature's chemistry; making use of carbon's ability to provide a stable skeleton for functional molecules. This has yielded new medicines and revolutionary materials such as plastics.

In order to create these complex chemicals, chemists need to be able to join carbon atoms together. However, carbon is stable and carbon atoms do not easily react with one another. The first methods used by chemists to bind carbon atoms together were therefore based upon various techniques for rendering carbon more reactive. Such methods worked when creating simple molecules, but when synthesizing more complex molecules chemists ended up with too many unwanted by-products in their test tubes.

Palladium-catalyzed cross coupling solved that problem and provided chemists with a more precise and efficient tool to work with. In the Heck reaction, Negishi reaction and Suzuki reaction, carbon atoms meet on a palladium atom, whereupon their proximity to one another kick-starts the chemical reaction.

Palladium-catalyzed cross coupling is used in research worldwide, as well as in the commercial production of for example pharmaceuticals and molecules used in the electronics industry.

Wednesday, October 6, 2010

Brain Cell Communication: Why It's So Fast


Billions of brain cells are communicating at any given moment. Like an organic supercomputer they keep everything going, from breathing to solving riddles, and "programming errors" can lead to serious conditions such as schizophrenia, Parkinson's Disease and attention-deficit hyperactivity disorder.
Vesicle with three "linking bridges". (Credit: Image courtesy of University of Copenhagen)

The brain uses biochemical signal molecules

Today, the biochemical language of the nerve cells is the subject of intensive research right down at the molecular level, and for the first time researchers, some from the University of Copenhagen, have described just how nerve cells are capable of transmitting signals practically simultaneously.

The cells of the nervous system communicate using small molecule neurotransmitters such as dopamine, serotonin and noradrenalin. Dopamine is associated with cognitive functions such as memory, serotonin with mood control, and noradrenaline with attention and arousal.

The brain cell communication network, the synapses, transmit messages via chemical neurotransmitters packaged in small containers (vesicles) waiting at the nerve ends of the synapses. An electrical signal causes the containers and membrane to fuse and the neurotransmitters flow from the nerve ending to be captured by other nerve cells. This occurs with immense rapidity in a faction of a millisecond.

The vesicle uses three copies of the "linking bridge"

Researchers from the Universities of Copenhagen, Göttingen and Amsterdam have been studying the complex organic protein complexes that link vesicles and membrane prior to fusion, in order to find an explanation for the rapidity of these transmissions. They have discovered that the vesicle contains no fewer than three copies of the linking bridge or "SNARE complex."

With only one SNARE complex the vesicle takes longer to fuse with the membrane and the neurotransmitter is therefore secreted more slowly.

"The precursors for the SNARE complexes are present in the vesicles before they reach the target membrane," said Professor Jakob Balsev Sørensen from the Department of Neuroscience and Pharmacology at the University of Copenhagen. "Fast (synchronous) fusion is enabled when at least three of them work in tandem. If the vesicle only has one SNARE complex it can still fuse with the target membrane, but it takes much longer."

The discovery has just been published in Science.

"Our next step will be to investigate the factors that influence and regulate the number of SNARE complexes in the vesicles. Is this a way for the nerve cells to choose to communicate more or less rapidly, and is this regulation altered when the brain is diseased?", professor Sørensen says.

Nobel Prize in Physiology or Medicine 2010 Was Awarded to Robert G. Edwards for IVF Fertilization


Robert Edwards has been awarded the 2010 Nobel Prize for the development of human in vitro fertilization (IVF) therapy. His achievements have made it possible to treat infertility, a medical condition afflicting a large proportion of humanity including more than 10% of all couples worldwide.
In vitro fertilization. (Credit: iStockphoto)

As early as the 1950s, Edwards had the vision that IVF could be useful as a treatment for infertility. He worked systematically to realize his goal, discovered important principles for human fertilization, and succeeded in accomplishing fertilization of human egg cells in test tubes (or more precisely, cell culture dishes). His efforts were finally crowned by success on 25 July, 1978, when the world's first "test tube baby" was born. During the following years, Edwards and his co-workers refined IVF technology and shared it with colleagues around the world.

Approximately four million individuals have so far been born following IVF. Many of them are now adult and some have already become parents. A new field of medicine has emerged, with Robert Edwards leading the process all the way from the fundamental discoveries to the current, successful IVF therapy. His contributions represent a milestone in the development of modern medicine.

Infertility -- a medical and psychological problem

More than 10% of all couples worldwide are infertile. For many of them, this is a great disappointment and for some causes lifelong psychological trauma. Medicine has had limited opportunities to help these individuals in the past. Today, the situation is entirely different. In vitro fertilization (IVF) is an established therapy when sperm and egg cannot meet inside the body.

Basic research bears fruit

The British scientist Robert Edwards began his fundamental research on the biology of fertilization in the 1950s. He soon realized that fertilization outside the body could represent a possible treatment of infertility. Other scientists had shown that egg cells from rabbits could be fertilized in test tubes when sperm was added, giving rise to offspring. Edwards decided to investigate if similar methods could be used to fertilize human egg cells.

It turned out that human eggs have an entirely different life cycle than those of rabbits. In a series of experimental studies conducted together with several different co-workers, Edwards made a number of fundamental discoveries. He clarified how human eggs mature, how different hormones regulate their maturation, and at which time point the eggs are susceptible to the fertilizing sperm. He also determined the conditions under which sperm is activated and has the capacity to fertilize the egg. In 1969, his efforts met with success when, for the first time, a human egg was fertilized in a test tube.

In spite of this success, a major problem remained. The fertilized egg did not develop beyond a single cell division. Edwards suspected that eggs that had matured in the ovaries before they were removed for IVF would function better, and looked for possible ways to obtain such eggs in a safe way.

From experiment to clinical medicine

Edwards contacted the gynecologist Patrick Steptoe. He became the clinician who, together with Edwards, developed IVF from experiment to practical medicine. Steptoe was one of the pioneers in laparoscopy, a technique that was new and controversial at the time. It allows inspection of the ovaries through an optical instrument. Steptoe used the laparoscope to remove eggs from the ovaries and Edwards put the eggs in cell culture and added sperm. The fertilized egg cells now divided several times and formed early embryos, 8 cells in size.

These early studies were promising but the Medical Research Council decided not to fund a continuation of the project. However, a private donation allowed the work to continue. The research also became the topic of a lively ethical debate that was initiated by Edwards himself. Several religious leaders, ethicists, and scientists demanded that the project be stopped, while others gave it their support.

The birth of Louise Brown -- an historic event

Edwards and Steptoe could continue their research thanks to the new donation. By analyzing the patients' hormone levels, they could determine the best time point for fertilization and maximize the chances for success. In 1978, Lesley and John Brown came to the clinic after nine years of failed attempts to have a child. IVF treatment was carried out, and when the fertilized egg had developed into an embryo with 8 cells, it was returned to Mrs. Brown. A healthy baby, Louise Brown, was born through Caesarian section after a full-term pregnancy, on 25 July, 1978. IVF had moved from vision to reality and a new era in medicine had begun.

IVF is refined and spreads around the world

Edwards and Steptoe established the Bourn Hall Clinic in Cambridge, the world's first centre for IVF therapy. Steptoe was its medical director until his death in 1988, and Edwards was its head of research until his retirement. Gynecologists and cell biologists from all around the world trained at Bourn Hall, where the methods of IVF were continuously refined. By 1986, 1,000 children had already been born following IVF at Bourn Hall, representing approximately half of all children born after IVF in the world at that time.

Today, IVF is an established therapy throughout the world. It has undergone several important improvements. For example, single sperm can be microinjected directly into the egg cell in the culture dish. This method has improved the treatment of male infertility by IVF. Furthermore, mature eggs suitable for IVF can be identified by ultrasound and removed with a fine syringe rather than through the laparoscope.

IVF is a safe and effective therapy. 20-30% of fertilized eggs lead to the birth of a child. Complications include premature births but are very rare, particularly when one egg only is inserted into the mother. Long-term follow-up studies have shown that IVF children are as healthy as other children.

Approximately four million individuals have been born thanks to IVF. Louise Brown and several other IVF children have given birth to children themselves; this is probably the best evidence for the safety and success of IVF therapy. Today, Robert Edwards' vision is a reality and brings joy to infertile people all over the world.

Powerful Supercomputer Peers Into the Origin of Life


Supercomputer simulations at the Department of Energy's Oak Ridge National Laboratory are helping scientists unravel how nucleic acids could have contributed to the origins of life.
New research at Oak Ridge National Laboratory explains how a ribonucleic acid enzyme, or ribozyme (pictured), uses magnesium ions (seen as spheres) to accelerate a significant reaction in organic chemistry. (Credit: Image courtesy of DOE/Oak Ridge National Laboratory)

A research team led by Jeremy Smith, who directs ORNL's Center for Molecular Biophysics and holds a Governor's Chair at University of Tennessee, used molecular dynamics simulation to probe an organic chemical reaction that may have been important in the evolution of ribonucleic acids, or RNA, into early life forms.

Certain types of RNA called ribozymes are capable of both storing genetic information and catalyzing chemical reactions -- two necessary features in the formation of life. The research team looked at a lab-grown ribozyme that catalyzes the Diels-Alder reaction, which has broad applications in organic chemistry.

"Life means making molecules that reproduce themselves, and it requires molecules and are sufficiently complex to do so," Smith said. "If a ribozyme like the Diels-Alderase is capable of doing organic chemistry to build up complex molecules, then potentially something like that could have been present to create the building blocks of life."

The research team found a theoretical explanation for why the Diels-Alder ribozyme needs magnesium to function. Computational models of the ribozyme's internal motions allowed the researchers to capture and understand the finer details of the fast-paced reaction. The static nature of conventional experimental techniques such as chemical probing and X-ray analysis had not been able to reveal the dynamics of the system.

"Computer simulations can provide insight into biological systems that you can't get any other way," Smith said. "Since these structures are changing so much, the dynamic aspects are difficult to understand, but simulation is a good way of doing it."

Smith explained how their calculations showed that the ribozyme's internal dynamics included an active site, or "mouth," which opens and closes to control the reaction. The concentration of magnesium ions directly impacts the ribozyme's movements.

"When there's no magnesium present, the mouth closes, the substrate can't get in, and the reaction can't take place. We found that magnesium ions bind to a special location on the ribozyme to keep the mouth open," Smith said.

The research was published as "Magnesium-Dependent Active-Site Conformational Selection in the Diels-Alderase Ribozyme" in the Journal of the American Chemical Society. The research team included Tomasz Berezniak and Mai Zahran, who are Smith's graduate students, and Petra Imhof and Andres Jäschke from the University of Heidelberg.

Smith's research was supported by Laboratory Directed Research and Development program funding. The bulk of the simulations were performed on the Kraken supercomputer at the UT/ORNL National Institute for Computational Sciences, supported by a National Science Foundation Teragrid allocation, and the resulting data were analyzed on the Heidelberg Linux Cluster System at the Interdisciplinary Center for Scientific Computing of the University of Heidelberg.