Thursday, March 28, 2013

Pinning down the pain

Pinning down the pain [ Back to EurekAlert! ] Public release date: 27-Mar-2013
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Contact: Scott LaFee
slafee@ucsd.edu
619-543-6163
University of California - San Diego

Schwann cell protein plays major role in neuropathic pain

An international team of scientists, led by researchers at the University of California, San Diego School of Medicine, says a key protein in Schwann cells performs a critical, perhaps overarching, role in regulating the recovery of peripheral nerves after injury. The discovery has implications for improving the treatment of neuropathic pain, a complex and largely mysterious form of chronic pain that afflicts over 100 million Americans.

The findings are published in the March 27, 2013 issue of the Journal of Neuroscience.

Neuropathic pain occurs when peripheral nerve fibers (those outside of the brain and spinal cord) are damaged or dysfunctional, resulting in incorrect signals sent to the brain. Perceived pain sensations are frequently likened to ongoing burning, coldness or "pins and needles." The phenomenon also involves changes to nerve function at both the injury site and surrounding tissues.

Not surprisingly, much of the effort to explain the causes and mechanisms of neuropathic pain has focused upon peripheral nerve cells themselves. The new study by principal investigator Wendy Campana, PhD, associate professor in UC San Diego's Department of Anesthesiology, with colleagues at UC San Diego and in Japan, Italy and New York, points to a surprisingly critical role for Schwann cells a type of glial support cell.

Schwann cells promote the growth and survival of neurons by releasing molecules called trophic factors, and by supplying the myelin used to sheathe neuronal axons. Myelination of axons helps increase the speed and efficacy of neural impulses, much as plastic insulation does with electrical wiring.

"When Schwann cells are deficient they can't perform these functions," said Campana. "Impaired neurons remain impaired and acute damage may transition to become chronic damage, which can mean lasting neuropathic pain for which there is currently no effective treatment."

Specifically, the scientists investigated a protein called LRP1, which Campana and colleagues had first identified in 2008 as a potential basis for new pain-relieving drugs due to its signal-blocking, anti-inflammatory effects.

The researchers found that mice genetically engineered to lack the gene that produces LRP1 in Schwann cells suffered from abnormalities in axon myelination and in Remak bundles multiple non-myelinated pain transmitting axons grouped together by Schwann cells. In both cases, one result was neuropathic pain, even in the absence of an actual injury.

Moreover, injured mice lacking the LRP1 gene showed accelerated cell death and poor neural repair compared to controls, again resulting in significantly increased and sustained neuropathic pain and loss of motor function.

"LRP1 helps mediate normal interactions between Schwann cells and axons and, when peripheral nerves have been injured, plays a critical role in regulating the steps that lead to eventual nerve regeneration," said Campana. "When LRP1 is deficient, defects and problems become worse. They may go from acute to chronic, with increasing levels of pain."

Campana and others are now pursuing development of a small molecule drug that can mimic LRP1, binding to receptors in Schwann cells to improve their health and ability to repair damaged nerve cells. "By targeting Schwann cells and LRP1, I think we can improve cells' response to injury, including reducing or eliminating chronic neuropathic pain."

###

Co-authors include Sumihisa Orita, Kazuyo Yamauchi and Tetsuhiro Ishikawa, UCSD Department of Anesthesiology and Department of Orthopedic Surgery, Chiba University, Japan; Kenneth Henry, Elisabetta Mantuano and Melanie Pollack, UCSD Department of Anesthesiology; Alice De Corato, UCSD Department of Anesthesiology and Department of Pharmacology, Cattolica University, Italy; M. Laura Feltri and Lawrence Wrabetz, Hunter James Kelly Research Institute, State University of New York at Buffalo; Alban Gaultier and Steven L. Gonias, UCSD Department of Pathology; Mark Ellisman, UCSD Department of Neurosciences; and Kazuhisa Takahashi, Department of Orthopedic Surgery, Chiba University, Japan.

Funding for this research come, in part, from the National Institutes of Health (NINDS grants R01 NS-057456, R01 NS-054671, P30 NS47101, NCRR 5P41RR004050-24 and NIGMS P41GM103412-24) and the Uehara Memorial Foundation.


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Pinning down the pain [ Back to EurekAlert! ] Public release date: 27-Mar-2013
[ | E-mail | Share Share ]

Contact: Scott LaFee
slafee@ucsd.edu
619-543-6163
University of California - San Diego

Schwann cell protein plays major role in neuropathic pain

An international team of scientists, led by researchers at the University of California, San Diego School of Medicine, says a key protein in Schwann cells performs a critical, perhaps overarching, role in regulating the recovery of peripheral nerves after injury. The discovery has implications for improving the treatment of neuropathic pain, a complex and largely mysterious form of chronic pain that afflicts over 100 million Americans.

The findings are published in the March 27, 2013 issue of the Journal of Neuroscience.

Neuropathic pain occurs when peripheral nerve fibers (those outside of the brain and spinal cord) are damaged or dysfunctional, resulting in incorrect signals sent to the brain. Perceived pain sensations are frequently likened to ongoing burning, coldness or "pins and needles." The phenomenon also involves changes to nerve function at both the injury site and surrounding tissues.

Not surprisingly, much of the effort to explain the causes and mechanisms of neuropathic pain has focused upon peripheral nerve cells themselves. The new study by principal investigator Wendy Campana, PhD, associate professor in UC San Diego's Department of Anesthesiology, with colleagues at UC San Diego and in Japan, Italy and New York, points to a surprisingly critical role for Schwann cells a type of glial support cell.

Schwann cells promote the growth and survival of neurons by releasing molecules called trophic factors, and by supplying the myelin used to sheathe neuronal axons. Myelination of axons helps increase the speed and efficacy of neural impulses, much as plastic insulation does with electrical wiring.

"When Schwann cells are deficient they can't perform these functions," said Campana. "Impaired neurons remain impaired and acute damage may transition to become chronic damage, which can mean lasting neuropathic pain for which there is currently no effective treatment."

Specifically, the scientists investigated a protein called LRP1, which Campana and colleagues had first identified in 2008 as a potential basis for new pain-relieving drugs due to its signal-blocking, anti-inflammatory effects.

The researchers found that mice genetically engineered to lack the gene that produces LRP1 in Schwann cells suffered from abnormalities in axon myelination and in Remak bundles multiple non-myelinated pain transmitting axons grouped together by Schwann cells. In both cases, one result was neuropathic pain, even in the absence of an actual injury.

Moreover, injured mice lacking the LRP1 gene showed accelerated cell death and poor neural repair compared to controls, again resulting in significantly increased and sustained neuropathic pain and loss of motor function.

"LRP1 helps mediate normal interactions between Schwann cells and axons and, when peripheral nerves have been injured, plays a critical role in regulating the steps that lead to eventual nerve regeneration," said Campana. "When LRP1 is deficient, defects and problems become worse. They may go from acute to chronic, with increasing levels of pain."

Campana and others are now pursuing development of a small molecule drug that can mimic LRP1, binding to receptors in Schwann cells to improve their health and ability to repair damaged nerve cells. "By targeting Schwann cells and LRP1, I think we can improve cells' response to injury, including reducing or eliminating chronic neuropathic pain."

###

Co-authors include Sumihisa Orita, Kazuyo Yamauchi and Tetsuhiro Ishikawa, UCSD Department of Anesthesiology and Department of Orthopedic Surgery, Chiba University, Japan; Kenneth Henry, Elisabetta Mantuano and Melanie Pollack, UCSD Department of Anesthesiology; Alice De Corato, UCSD Department of Anesthesiology and Department of Pharmacology, Cattolica University, Italy; M. Laura Feltri and Lawrence Wrabetz, Hunter James Kelly Research Institute, State University of New York at Buffalo; Alban Gaultier and Steven L. Gonias, UCSD Department of Pathology; Mark Ellisman, UCSD Department of Neurosciences; and Kazuhisa Takahashi, Department of Orthopedic Surgery, Chiba University, Japan.

Funding for this research come, in part, from the National Institutes of Health (NINDS grants R01 NS-057456, R01 NS-054671, P30 NS47101, NCRR 5P41RR004050-24 and NIGMS P41GM103412-24) and the Uehara Memorial Foundation.


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AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert! system.


Source: http://www.eurekalert.org/pub_releases/2013-03/uoc--pdt032713.php

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BlackBerry Posts Promising Q4 Results After BB10 Launch: EPS Of $0.22, Revenue Of $2.7B, ~1M Z10s Shipped

z10-6For the past year BlackBerry has been trying to prove to the world that it?s not a mobile has-been just yet, and that all came to a head earlier this year when the company finally released BlackBerry 10 mobile to the masses. While the company?s future is still unclear, BlackBerry released its fiscal Q4 2013 earnings early this morning and they?re more impressive than you would expect for a company going through some major upheavals.

Source: http://feedproxy.google.com/~r/Techcrunch/~3/_Uh0_yyU9Fo/

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Girls accused of threatening Steubenville rape victim released, ordered to halt social media posts

By Jeff Black, Staff Writer, NBC News

Two teenage girls accused of threatening the 16-year-old victim in the Steubenville, Ohio, rape case were released on house arrest Wednesday and ordered not to use social media.

Just days after two teenage boys from Steubenville, Ohio, were convicted of rape, two teen girls were arrested and charged with threatening the victim over Twitter. NBC's Ron Allen reports.

The girls were arrested in the aftermath of the guilty verdicts of two high school football player, Trent Mays, 17, and Ma?lik Richmond, 16, who a judge found raped the West Virginia girl during a night of heavy drinking.

The case drew national notoriety to the small Ohio town where the successful ?Big Red? high school football team is a source of community pride.

Social media postings of images, video and text messages played a unique role in the prosecution?s case. A 12-minute video shocked many for the callous and profane way the boys discussed raping the victim.

In Wednesday's juvenile court hearing, defense attorneys for the two accused girls entered a denial to the charges, equivalent to a not guilty plea, NBC station WTOV reported.

The judge and prosecution also discussed releasing information from the girls? twitter accounts and cell phones.

In addition releasing the girls to their homes, the judge ordered them not to contact the victim, a West Virginia resident. The accused girls had been held at a juvenile detention center.

The original rape trial verdict was announced on Sunday, March 18, and by the next day State Attorney Mike DeWine had charged a 16-year-old girl with aggravated menacing for threatening the victim?s live on Twitter, and a charged? a 15-year-old girl with menacing and threatening bodily harm to the victim on Facebook.

According to NBC station WPXI, which cited an investigator, one of the threats on Twitter said, ?You ripped my family apart. You made my cousin cry. So when I see you it?s going to be homicide.?

A wide-ranging investigation is also under way that could lead to more charges in the case, DeWine said after the verdict.

Related:

Two teen girls charged for online threats against Steubenville rape victim
Verdicts in Steubenville high school rape trial
Steubenville high school rape trial zeroes in on texts, photos, video

Source: http://feeds.nbcnews.com/c/35002/f/653381/s/2a104f47/l/0Lusnews0Bnbcnews0N0C0Inews0C20A130C0A30C270C17488420A0Egirls0Eaccused0Eof0Ethreatening0Esteubenville0Erape0Evictim0Ereleased0Eordered0Eto0Ehalt0Esocial0Emedia0Eposts0Dlite/story01.htm

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Wednesday, March 27, 2013

Column: Bubbles in food prices: John Kemp

By John Kemp

LONDON (Reuters) - A thoughtful new paper from researchers at the University of Illinois marks a significant step forward in research on how commodity futures prices are formed.

Until recently, the academic and policy debate about futures price formation has been locked in an acrimonious and polarized standoff between market fundamentalists, who insist all price moves reflect supply and demand fundamentals, and those writers who blame speculators for every rise in food and fuel prices.

Both views tend to be colored by the policy outcomes researchers favor. Anti-poverty campaigners focus on the role of speculation because they want governments to impose more controls on the cost of food and fuel. Free-market economists stress the role of fundamentals to deny governments any ammunition to meddle.

Both positions are extreme and unconvincing.

Now Xiaoli Etienne, Scott Irwin and Philip Garcia have published an innovative paper examining the evidence for temporary price bubbles in markets where prices are otherwise driven by fundamental factors.

According to the authors, futures prices for grains, livestock and soft commodities like sugar have all exhibited multiple bubbles over the last four decades, with bubbles more common in the 1970s and again in the 2000s than during the 1980s and 1990s.

Bubbles pre-date the rising popularity of indexing strategies and the "financialisation" of commodity markets. There is no evidence bubbles have become more frequent or larger following the entry of more financial investors into commodity futures markets since 2005.

"Bubbles existed long before commodity index traders arrived and the process of commodity market financialisation started," according to a paper on "Bubbles in Food Commodity Markets: Four Decades of Evidence" presented at an IMF seminar in Washington on March 21.

In fact most of the biggest and long-lasting bubbles occurred in 1971-76. Financialisation may have ensured bubble-like price movements are now smaller and reverse more quickly.

"Compared to the post-2000 years, speculators and irrational traders (may have) played a greater role influencing prices in the 1970s because markets were less actively traded. The arrival of new traders in recent years, coupled with a dramatic increase in trading volumes, has increased market liquidity, apparently reducing the frequency of bubbles," the authors write (http://www.imf.org/external/np/seminars/eng/2012/commodity/pdf/irwin.pdf).

PRICE MOMENTUM

The persistence of bubbles remains perplexing. The authors speculate bubbles may be driven by herding behavior, momentum trading or other "noise traders".

"One possible explanation may be that markets are sometimes driven by herd behavior unrelated to economic realities ... As markets overreact to new information, commodity prices may thus show excess volatility and become explosive."

"It may also be that there are many positive feedback traders in the market who buy more when the price shows an upward trend and sell in the opposite situation. When there are too many feedback traders for the markets to absorb, speculative bubbles can occur in which expectations of higher future prices support high current prices."

"It may be fads, herding behavior, feedback trading, or other noise traders that have long plagued futures markets were highly influential in recent price behavior. Recent empirical evidence does suggest that herding behavior exists in futures markets among hedge funds and floor participants."

The paper concludes with an appeal for more research to identify the source of bubble-like price behavior.

GREAT LEAP FORWARD

In most other asset classes, it is now accepted market prices are basically driven by fundamentals, especially in the medium and long run, but in the short term can department from them, sometimes significantly, as a result of speculative factors.

As billionaire investor Warren Buffett noted in 1988 about the hardline believers in efficient market theory: "Observing correctly that the market was frequently efficient, they went on to conclude incorrectly that it was always efficient. The difference between these propositions is night and day."

Now a new generation of researchers are developing theories which allow for a combination of both fundamental and speculative factors to affect commodity futures prices.

Etienne, Irwin and Garcia's paper is a big step forward because it carefully distinguishes between the influence of the commodity index traders and the short-term bubbles evident in commodity futures prices.

It also shows how behavioral factors could be integrated into a fundamental theory of commodity futures pricing, as has been accepted in every other major asset class.

Crucially, it shows how herding, momentum-based trading strategies and other noise trading may cause futures prices temporarily to depart from fundamentally determined levels, but suggests such deviations have been relatively brief and reversed within weeks or months.

Bubbles may always have been part of the operation of futures markets. For a sample of around 40 annual contracts in 12 different commodities, the authors found bubble-like behavior in about a third of the contract months studied. Bubbles occurred most frequently in sugar (55 percent of contracts studied) and least frequently in feeder cattle (25 percent) and wheat (24 percent).

BEHAVIOUR AND FUNDAMENTALS

The University of Illinois' Department of Agricultural and Consumer Economics is one of the most respected institutions in the field of commodities and derivatives, so the findings cannot be readily dismissed.

In some ways, commodity research is catching up with developments elsewhere. The formation and subsequent collapse of bubbles in other markets has been extensively studied by George Soros ("The Alchemy of Finance" 1987), Didier Sornette ("Why Stock Markets Crash" 2003) and Robert Shiller ("Irrational Exuberance" 2009) for 25 years.

Etienne, Irwin and Garcia have shown how the same approach could help improve understanding of commodity futures markets.

The authors observe "speculative bubbles are not isolated phenomena in agricultural markets, but appear in other futures markets including energy and metals markets as well" citing work by Phillips and Yu ("Dating the timeline of financial bubbles" 2011) and Gilbert ("Speculative Influences on Commodity Futures Prices" 2010).

The paper does not investigate energy futures markets. But the approach could be usefully applied to see if energy and metals markets exhibit similar bubble phenomena.

A theory of commodity price formation that embraces both fundamental and behavioral factors would provide a much richer and more realistic understanding of how futures prices are set.

Accepting that bubbles occur in food (and possibly fuel) prices does not mean they should be regulated out of existence.

Bubbles may be an integral part of the normal process of price formation in any financial market, including commodities, as investors grope towards an equilibrium in the face of incomplete information and limited liquidity.

Trying to eliminate bubbles through regulation may do more harm than good. Accepting temporary bubbles may be the price for allowing the market to perform its long-term function of price discovery.

But the paper should finally move the academic and policy debate beyond its polarized focus on whether speculation impacts commodity futures prices to ask a more nuanced question: how?

(Editing by William Hardy)

Source: http://news.yahoo.com/column-bubbles-food-prices-john-kemp-211121742.html

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The art of the nap: Tilda Swinton at MoMA

NEW YORK (AP) ? It's not the kind of performance that will win her another Academy Award, but Tilda Swinton certainly has them buzzing at the Museum of Modern Art.

But keep it down, please. She's trying to sleep.

The "Moonrise Kingdom star has been engaging in a different kind of performance art. She's presenting a one-person piece called "The Maybe," in which she lies sleeping in a glass box for the day. The first performance was over the weekend, and the museum won't say if there's a schedule for when exactly it will come back for six other performances.

On Monday, the display drew a line of spectators that wound through a whole second-floor gallery into a museum hallway.

Erwin Aschenbrenner, a bemused German tourist, said it "just what you'd expect to see at MoMA."

The actress "is so pale and not moving in there that she looks like she's dead," said Robbie von Kampen, 20, a philosophy major at Bard College, north of New York City.

But after about seven hours a day of the shuteye pose on a white mattress in the glass box ? with only a carafe of water and a glass to get her through ? Swinton can stretch and walk off into the Manhattan night. But only when spectators leave.

So what's the point?

"This makes me think about myself, looking at her," said Quinn Moreland, 20, also a Bard student, majoring in art history.

"You don't usually get to stare at somebody like this; it makes me self-conscious," she explained.

Added von Kampen, "Yeah, it's socially unacceptable ? it's kinda creepy."

No one, not even museum curators, could say whether the thin, mostly immobile Swinton is actually getting some sleep while people stare at her.

At least Swinton was comfortable. She wore a pair of grubby sneakers, dark sporty slacks and a checkered shirt. Her glasses lay on the mattress.

But no snacks were in sight. And none could be offered in the closed chamber.

Swinton also starred in a glass box in 1995 at London's Serpentine Gallery ? seven days, eight hours a day ? in an exhibition seen by 22,000 people.

The next year, she repeated the spectacle at the Museo Barracco in Rome.

Source: http://news.yahoo.com/art-nap-tilda-swinton-moma-222107593.html

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Eutelsat Communications + JSC Global... FTA + More... - Satnews ...

Eutelsat Communications + JSC Global... FTA + More... (SatBroadcasting??Capacity)

[SatNews] Georgian media company JSC Global Contact Consulting has selected...

...Eutelsat Communications for a new satellite broadcasting platform dubbed Global TV. The company has signed a multi-year lease for capacity on the Eutelsat 36B satellite, using the widebeam footprint that provides premium coverage of Georgia, surrounding regions and Western Europe. JSC Global Contact Consulting will initiate satellite broadcasting this month, starting with four free-to-air (FTA) channels and progressively expanding to include both Georgian and international channels. To accelerate access to the new platform, JSC plans to install several thousand dishes across Georgia over the next two years that will be pointed to Eutelsat 36B at 36 degrees East.

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Source: http://www.satnews.com/story.php?number=2078697412

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Sunday, March 24, 2013

Agriculture disputes threaten new US-EU talks

(AP) ? President Barack Obama used Washington's grandest stage ? the State of the Union speech ? to announce negotiations with Europe aimed at creating the world's largest free trade agreement. Just weeks later, there are signs that old agriculture disputes could be deal-killers.

European Union leaders don't want the negotiations to include discussions on their restrictions on genetically modified crops and other regulations that keep U.S. farm products out of Europe. But Obama says it's hard to imagine an agreement that doesn't address those issues. Powerful U.S. agricultural lobbies will do their best to make sure Congress rejects any pact that fails to address the restrictions.

"Any free trade agreement that doesn't cover agriculture is in trouble," said Cathleen Enright, executive vice president at the Biotechnology Industry Organization, which promotes biotechnology, including genetically modified products.

That would threaten the dream of a behemoth free trade deal between the world's two largest trading partners that together account for more than half of the world economy. It would lower tariffs and remove other trade barriers for most industries. Some analysts say the deal could boost each economy by more than a half-percentage point annually and significantly lower the cost of goods and services for consumers.

Agricultural issues have long bedeviled attempts to expand free trade across the Atlantic and have led each side to file complaints against the other before the World Trade Organization, an arbitrator in trade disputes. While the U.S. protests EU restrictions, Europeans want the U.S. to reduce agricultural subsidies.

Genetically modified organisms, or GMOs, have been a core part of the dispute. Agricultural scientists change the genetic makeup of agricultural products to improve their quality and boost production. In Europe, there is widespread public opposition to GMOs. The EU argues that the risks of altering the genetic pool are unknown. It has strict rules and imposes a heavy burden of proof before such crops can be grown or imported in the EU.

U.S. companies say that genetically modified products have been proved safe by scientific studies and are being excluded based on irrational fears. They accuse Europe of trying to help their own farmers by keeping out American products.

While they have little expectation that the EU would end the restrictions, they say it would be a victory if it clarified what it describes as opaque rules and also set timelines for considering products. Regulators now take what they call a precautionary approach, declining approval of products until they can be more certain of their safety.

But any move to water down the regulations could provoke a backlash in Europe.

"My reading of the mood in Europe around genetically modified crops is that it's extremely negative," said Paul DeGrauwe, a professor of economics at the London School of Economics. "It's going to be very difficult."

Indeed, the top EU trade negotiator, Commissioner Karel De Gucht, seemed to rule out a compromise in remarks this month: "A future deal will not change the existing legislation. Let me repeat: no change."

The U.S. and the EU have similarly intractable disagreements on what the two sides call sanitary issues in meats. U.S. poultry products are restricted in the EU because U.S. companies use chlorine to sanitize the meat. Pork is also restricted because U.S. farmers use a feed additive that makes pigs leaner. The two sides partially resolved disputes over U.S. beef after an agreement that U.S. farmers would restrict hormones in cows intended for the European market.

Some European officials say the agricultural differences should be discussed after a major trade deal is completed. This month, French President Francois Hollande called for excluding sensitive issues, including the sanitary standards, from the talks. In the past, France has been among the most adamant of the European countries about protecting agricultural interests.

Obama, in a talk with his export council this month, suggested this could be a deal-breaker.

"There are certain countries whose agricultural sector is very strong, who tended to block at critical junctures the kinds of broad-based trade agreements that would make it a good deal for us," he said. "If one of the areas where we've got the greatest comparative advantage is cordoned off from an overall trade deal, it's very hard to get something going."

Powerful U.S. agricultural groups could probably block a trade deal from winning approval in Congress. In interviews, representatives of many of these groups said they would oppose a deal that didn't address the regulatory differences.

Robert Thompson, an academic at Johns Hopkins University and a former economist for the Agriculture Department, said that the agricultural issues could easily upend the talks.

"I'm not expecting an agreement to emerge any time soon," he said. "I'm thinking years."

Of course, the rhetoric at the beginning of talks might not preclude compromise in the end. In his talk with the export council, Obama expressed optimism. He noted that austerity measures in response to the debt crisis in the EU have caused European countries to look to a free trade deal as a rare opportunity to boost the economy and improve competitiveness.

"I think they are hungrier for a deal than they have been in the past," he said.

___

Melvin reported from Brussels.

___

Follow Desmond Butler on Twitter at http://twitter.com/desmondbutler

Follow Don Melvin on Twitter at http://twitter.com/Don_Melvin

Associated Press

Source: http://hosted2.ap.org/APDEFAULT/89ae8247abe8493fae24405546e9a1aa/Article_2013-03-23-US-EU-Trade/id-98923ae97ed24f47829b6e6d7a514692

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Researchers use metamaterials to observe giant photonic spin hall effect

Friday, March 22, 2013

Researchers with the U.S. Department of Energy (DOE)'s Lawrence Berkeley National Laboratory (Berkeley Lab) have once again demonstrated the incredible capabilities of metamaterials ? artificial nanoconstructs whose optical properties arise from their physical structure rather than their chemical composition. Engineering a unique two-dimensional sheet of gold nanoantennas, the researchers were able to obtain the strongest signal yet of the photonic spin Hall effect, an optical phenomenon of quantum mechanics that could play a prominent role in the future of computing.

"With metamaterial, we were able to greatly enhance a naturally weak effect to the point where it was directly observable with simple detection techniques," said Xiang Zhang, a faculty scientist with Berkeley Lab's Materials Sciences Division who led this research. "We also demonstrated that metamaterials not only allow us to control the propagation of light but also allos control of circular polarization. This could have profound consequences for information encoding and processing."

Zhang is the corresponding author of a paper describing this work in the journal Science. The paper is titled "Photonic Spin Hall Effect at Metasurfaces." Co-authors are Xiaobo Yin, Ziliang Ye, Jun Sun Rho and Yuan Wang.

The spin Hall effect, named in honor of physicist Edwin Hall, describes the curved path that spinning electrons follow as they move through a semiconductor. The curved movement arises from the interaction between the physical motion of the electron and its spin ? a quantized angular momentum that gives rise to magnetic moment. Think of a baseball pitcher putting spin on a ball to make it curve to the left or right.

"Light moving through a metal also displays the spin Hall effect but the photonic spin Hall effect is very weak because the spin angular momentum of photons and spin-orbit interactions are very small," says Xiaobo Yin, a member of Zhang's research group and the lead author of the Science paper. "In the past, people have managed to observe the photonic spin Hall effect by generating the process over and over again to obtain an accumulative signal, or by using highly sophisticated quantum measurements. Our metamaterial makes the photonic spin Hall effect observable even with a simple camera."

Metamaterials have garnered a lot of attention in recent years because their unique structure affords electromagnetic properties unattainable in nature. For example, a metamaterial can have a negative index of refraction, the ability to bend light backwards, unlike all materials found in nature, which bend light forward. Zhang, who holds the Ernest S. Kuh Endowed Chair Professor of Mechanical Engineering at the University of California (UC) Berkeley, where he also directs the National Science Foundation's Nano-scale Science and Engineering Center, has been at the forefront of metamaterials research. For this study, he and his group fashioned metamaterial surfaces about 30 nanometers thick (a human hair by comparison is between 50,000 and 100,000 nanometers thick). These metasurfaces were constructed from V-shaped gold nanoantennas whose geometry could be configured by adjusting the length and orientation of the arms of the Vs.

"We chose eight different antenna configurations with optimized geometry parameters to generate a linear phase gradient along the x direction," says Yin. "This enabled us to control the the propagation of the light and introduce strong photon spin-orbit interactions through rapid changes in direction. The photonic spin Hall effect depends on the curvature of the light's trajectory, so the sharper the change in propagation direction, the stronger the effect."

Since the entire metasurface sample measured only 0.3 millimeters, a 50-millimeter lens was used to project the transmission of the light through the metamaterial onto a charge-coupled device (CCD) camera for imaging. From the CCD images, the researchers determined that both the control of light propagation and the giant photonic spin Hall effect were the direct results of the designed meta-material. This finding opens up a wealth of possibilities for new technologies.

"The controllable spin-orbit interaction and momentum transfer between spin and orbital angular momentum allows us to manipulate the information encoded on the polarization of light, much like the 0 and 1 of today's electronic devices," Yin says. "But photonic devices could encode more information and provide greater information security than conventional electronic devices."

Yin says the ability to control left and right circular polarization of light in metamaterial surfaces should allow for the formation of optical elements, like highly coveted "flat lenses," or the management of light polarization without using wave plates.

"Metamaterials provide us with tremendous design freedom that will allow us to modulate the strength of the photonic spin Hall effect at different spatial locations," Yin says. "We knew the photonic spin Hall effect existed in nature but it was so hard to detect. Now, with the right metamaterials we can not only enhance this effect we can harness it for our own purposes."

###

DOE/Lawrence Berkeley National Laboratory: http://www.lbl.gov

Thanks to DOE/Lawrence Berkeley National Laboratory for this article.

This press release was posted to serve as a topic for discussion. Please comment below. We try our best to only post press releases that are associated with peer reviewed scientific literature. Critical discussions of the research are appreciated. If you need help finding a link to the original article, please contact us on twitter or via e-mail.

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Source: http://www.labspaces.net/127407/Researchers_use_metamaterials_to_observe_giant_photonic_spin_hall_effect

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EXCLUSIVE: Mobb Deep Ready To Reunite And Forget Feud

'The music is the most important thing and our love for each other,' Prodigy tells MTV News.
By Rob Markman


Mobb Deep
Photo: MTV News

Source: http://www.mtv.com/news/articles/1704218/mobb-deep-reunite-post-feud.jhtml

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Thursday, March 21, 2013

Discovery of new drug to combat malaria

Mar. 20, 2013 ? University of South Florida researchers played a key role in an international multidisciplinary project that has yielded a promising new antimalarial drug with the potential to cure the mosquito-borne disease and block its transmission with low doses.

Roman Manetsch, PhD, USF associate professor of chemistry, and Dennis Kyle, PhD, USF professor of global health, were co-leaders of the USF team, which helped to discover and develop a series of potent compounds to combat malaria known as the 4-(1H)-quinolone-3-diarylethers, or quinolones.

The USF researchers were part of larger Medicines for Malaria Venture (MMV) project team including Oregon Health & Science University in Portland, Drexel University in Philadelphia, and Monash University in Australia.

The researchers narrowed the most effective drug candidates in the quinolones series to one lead drug -- ELQ-300 -- now moving toward clinical testing.

The project team's findings are published today in the journal Science Translational Medicine. USF's Alexis LaCrue, PhD, a research associate in Kyle's laboratory, was a co-first author for the paper along with Aaron Nilsen, PhD, of Portland VA Medical Center.

In initial preclinical tests, the lead drug demonstrated impressive preventive and transmission-blocking -- and a low likelihood for developing rapid resistance to major strains of malaria parasites.

In addition, ELQ-300 could likely be produced more cheaply than existing antimalarial drugs -- a major advantage in treating a tropical disease that kills nearly one million people a year and causes recurring bouts of severe and incapacitating illness, most often among poor people in developing countries.

"This is one of the first drugs ever to kill the malaria parasite in all three stages of its life cycle," said Kyle, a member of the USF College of Public Health's Global Infectious Diseases Research team. "So, it may become part of a new-generation therapy that not only treats sick people and prevents them from getting ill, but also blocks the transmission of malaria from mosquitoes to humans ? If the drug can break the parasite life cycle, we may ultimately eradicate the disease."

New life from an old class of compounds

The new drug class identified by the researchers were derived from the first antimalarial quinolone, endochin, discovered more than 60 years ago but never pursued as a treatment because it appeared not to work in humans.

Using new technology to optimize the quinolones, the MMV project team demonstrated that these compounds were indeed highly effective against Plasmodium falciparum, the most lethal strain of malaria, and Plasmodium vivax, the major cause of malaria outside Africa. The quinolones target both the liver and blood stages of the parasite as well as the forms critical for disease transmission.

"This was a very challenging project requiring years of hard work, collaboration across disciplines, and a good portion of luck," said Manetsch, whose laboratory specializes in medicinal chemistry, drug discovery and development of novel chemical probes to characterize drug-protein interactions.

Optimizing drug success against a complex parasite life cycle

In humans, the malaria parasite targets the liver after it enters the bloodstream through the bite of an infected mosquito. Once inside the liver, the infecting parasites for most types of malaria multiply and rupture liver cells, escaping back into the bloodstream -- although sometimes parasites can remain dormant in the liver for extended periods. The parasites, now modified to attack red blood cells, rapidly create more parasites, which spread throughout the bloodstream in waves.

The researchers needed to find and fine-tune a drug with a long half-life both to prevent malaria and to offer long-term protection against reinfection.

"It was a balancing act to optimize an antimalarial drug so that it was soluble and metabolically stable, without compromising its potency," Manetsch said. "We wanted a compound that within an individual would not break down too quickly, remain circulating in the blood for a long enough period to kill the parasites, and be highly active in blocking transmission in rodent models of malaria."

The antimalarial drug developed needed to be potent enough to work without harmful or bothersome side effects.

ELQ-300 targets a protein complex of the mitochondria that is integral for the energy household of a cell, Manetsch said. That's good when you're trying to incapacitate a malaria parasite's powerhouse, but the same hit in a human's mitochondria could be disastrous, he added.

So, Manetsch, with the help of Kyle's expertise in parasitology, structurally modified the quinolone scaffold so that the drug candidate ELQ-300 would selectively hit only the malaria parasite's target while sparing the human mitochondria.

Antimalarial drug resistance: A global health threat

With the rapid emergence of multi-drug resistant strains of malaria, the need to find new drugs capable of delaying or preventing drug resistance has become even more pressing, researchers say.

The quinolones, including ELQ-300, target the same biological pathway as atovaquone, the main component of Malarone, one of the newest combination drugs used to treat malaria. But, in repeated experiments ELQ-300 did not generate drug-resistant strains of the malaria parasite -- making it a significant improvement over atovaquone.

In addition, the new drug's design makes it more effective at lower doses, hopefully meaning fewer and smaller pills for patients at a lower cost, said Kyle, a technical advisor for the MMV team preparing ELQ-300 for clinical trials.

USF's Kyle and Manetsch, funded by National Institutes of Health grants totaling more than $2.5 million, continue to collaborate on research to identify and develop novel antimalarial drugs.

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The above story is reprinted from materials provided by University of South Florida (USF Health).

Note: Materials may be edited for content and length. For further information, please contact the source cited above.


Journal Reference:

  1. A. Nilsen, A. N. LaCrue, K. L. White, I. P. Forquer, R. M. Cross, J. Marfurt, M. W. Mather, M. J. Delves, D. M. Shackleford, F. E. Saenz, J. M. Morrisey, J. Steuten, T. Mutka, Y. Li, G. Wirjanata, E. Ryan, S. Duffy, J. X. Kelly, B. F. Sebayang, A.-M. Zeeman, R. Noviyanti, R. E. Sinden, C. H. M. Kocken, R. N. Price, V. M. Avery, I. Angulo-Barturen, M. B. Jimenez-Diaz, S. Ferrer, E. Herreros, L. M. Sanz, F.-J. Gamo, I. Bathurst, J. N. Burrows, P. Siegl, R. K. Guy, R. W. Winter, A. B. Vaidya, S. A. Charman, D. E. Kyle, R. Manetsch, M. K. Riscoe. Quinolone-3-Diarylethers: A New Class of Antimalarial Drug. Science Translational Medicine, 2013; 5 (177): 177ra37 DOI: 10.1126/scitranslmed.3005029

Note: If no author is given, the source is cited instead.

Disclaimer: This article is not intended to provide medical advice, diagnosis or treatment. Views expressed here do not necessarily reflect those of ScienceDaily or its staff.

Source: http://feeds.sciencedaily.com/~r/sciencedaily/top_news/top_science/~3/xBhto_JfcH4/130320142709.htm

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McDonald's Chicken McWrap To Be Added To Permanent Menu

NEW YORK ? McDonald's is adding a permanent new offering to its menu: chicken McWraps.

The world's biggest hamburger chain says the new sandwich wrap will come in three varieties ? Chicken & Bacon, Sweet Chili Chicken and Chicken & Ranch. The company already offers similar wraps in other parts of the world, including Europe.

The Oak Brook, Ill.-based chain says the McWraps use the same type of flour tortillas and chicken as its snack wraps, which were introduced in 2006. But two of the new McWraps will come with cucumbers, which the company says will mark the first time the vegetable will be part of its core menu. The wraps range from 360 to 600 calories, depending on whether people pick grilled or deep-fried chicken.

McDonald's Corp. has been stepping up the pace of its new menu offerings as it struggles to grow sales in the challenging economy. Last year, the company ousted the head of its U.S. division after a monthly sales figure fell for the first time in nearly a decade.

By refreshing its menu, McDonald's is hoping to hold onto customers as it faces a shifting industry and intensifying competition from the likes of Burger King and Wendy's. Next week, for instance, The Wendy's Co. plans to roll out its "Flatbread Grilled Chicken Sandwiches" in two varieties; an Asiago Ranch flavor will have 530 calories and the Honey Mustard flavor will have 370 calories.

The latest offerings also reflect the changing tastes of diners, who are increasingly looking for more premium ingredients with a healthier image ? even at fast-food chains. McDonald's, for example, is officially calling the new wraps "Premium McWraps." It also plans to offer a version of its Egg McMuffin made with egg whites starting April 22. And this week, Burger King Worldwide Inc. rolled out its first turkey burger following the success of turkey burgers at Carl's Jr. and Hardee's.

Dan Coudreaut, director of culinary innovation of McDonald's, says the wraps will be a new "platform" and that different varieties are already in the pipeline. These could include spicy or Cajun flavors, he said. In Europe, he noted, there is a shrimp McWrap.

"It's the benefit of McDonald's being a global system," he said, noting that the company can take successful items from around the world and adapt them to other markets. The Sweet Chili Chicken McWrap, for instance, was first offered in Australia.

Although the chicken McWraps officially launch nationwide next week, the company says many restaurants already have them. The suggested price for a wrap is $3.99.

National advertising is set to start April 1.

Also on HuffPost:

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Source: http://www.huffingtonpost.com/2013/03/20/mcdonalds-chicken-mcwrap_n_2918845.html

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Wednesday, March 20, 2013

Cinnamon Soho Easter menu, 5 Kingly Street, London W1B 5PF ...

You?ve heard the phase ?Christmas has come early?. For us it was Easter that came early? We were invited back to Cinnamon Soho?to sample?Vivek Singh?s?Easter egg-inspired menu and inspired it was too. (Read our full review of?Cinnamon Soho and?Cinnamon Kitchen.)

The spark that must have ignited this ?all ball? menu surely must have been Vivek?s?now-famous Bangla Scotch Egg which was included in ?The 100 Best Small Dishes in London 2012? category by Time Out.

Before I explain the menu I just had lift these pun-tastic lines straight from the press release? ?An Egg-cellent way to celebrate Easter and for just ?30 per person, diners can get egg-cited about a three-course menu inclusive of a cocktail to start and a selection of sharing appetisers?.

And how about this eggs-tra comment? ?Combining both sweet and savoury, head chef Ramachandran Raju?s menu takes our notion of the traditional Easter egg and turns it on its head, with delicious results to put a spiced spring in your step.?A cracking good way to mark the occasion.?

Sorry guys, you know we love you really, and I don?t want to sound egg-otistic but my puns have the eggs factor and I?m no spring chicken!

Anyway, here is the full menu?

Cinnamon Soho Easter menu, We Love Food, It's All We Eat

Tastes like Christmas, but still ?flipping? good!

Cocktail

Easter Egg Flip: Cognac, Tawny Port, Baileys, sugar and egg white, garnished with grated nutmeg

Cinnamon Soho Easter menu, We Love Food, It's All We Eat

Chatt were lucky to have escaped the lolly stick massacre

Appetisers?

Tangy potato chaat in semolina shell (v)

Indo-Chinese style stir-fried chicken and chilli

Fisherman?s-style crisp shrimp

Cinnamon Soho Easter menu, We Love Food, It's All We Eat

Fishy balls?

Cinnamon Soho Easter menu, We Love Food, It's All We Eat

?and the veggie option

Starter

Crab and cod balls on rock samphire ?nest?

or

Bengali-spiced vegetable balls with beetroot and raisin (v)

Cinnamon Soho Easter menu, We Love Food, It's All We Eat

?What you looking at?? growled Scotch egg

Cinnamon Soho Easter menu, We Love Food, It's All We Eat

These vegetarian kofta eggs were egg-cellent!

Main Course

?Nargis? lamb kofta curry with fragrant chicken biryani

Aromatic-spiced meatballs filled with soft-boiled egg, rich onion sauce

or

Vegetarian kofta, vegetable biryani (v)

Cinnamon Soho Easter menu, We Love Food, It's All We Eat

?You crack me up?? Vermicelli?s jokes had Kulfi in pieces!

Dessert

Spiced mango and pistachio kulfi, ?dum? cooked vermicelli

Right then, from the top. The?Easter Egg Flip tasted more of Christmas than Easter. The?Cognac, Baileys, sugar and grated nutmeg gave it a real festive flavour. But then again what does Easter taste like apart from chocolate? And maybe that was just too obvious for?Vivek and?Ramachandran.

The shared appetisers (two of each) are basically a scaled down taste teaser of the starters, in much the same way that the starters are to the main course? The potato chaat in a crispy semolina shell was my favourite, the tangy spud and crunchy coating a perfect combo. Be warned, the?Fisherman?s-style crisp shrimp had a fiery kick (note to readers, I?m a complete baby when it comes to spicy foods, Saff found the spice levels perfect).

We ordered one of each of the starters and shared them. I?d like to say we shared them equally, but that would be a lie? Saff preferred the?Bengali-spiced, yet sweet, vegetable balls leaving me to sweat my way through the hot chilli and tomato sauce that came with the?Crab and cod balls. The?rock samphire ?nests? were a nice touch too,?samphire is such an under-used vegetable.

Now on to the big balls? The lamb kofta was shaped into an ball (what else!) and was partnered by a?Bangla Scotch Egg. The vegetarian kofta, with morels and prunes, had the sublime balance of spice, flavour and heat as always achieved by the Cinnamon group.?The sides of a chicken and a vegetable biryani, as fragrant and delicious as they were, was maybe just a portion too much? We were getting full but still managed to eat clever little filo pastry ?hats? that sit atop the biryani sealing in the flavours and keeping the dishes warm.

On to dessert, by far the prettiest dish on the menu. Another ?nest?, this time made from sweetened?cooked vermicelli looked fab. The?pistachio kulfi, by far my favourite of any style and flavour of any ice-cream was given a splash of colour by the spiced mango pur?e.

Just as we were finishing our meal Vivek wandered over to ask what we thought of his new creations? And then showed us a picture on his phone of a man and his big balls! No it?s not what you think, it was a pic of a street performer he took in Trafalgar Square.

Before we sign off here?s a few more puns? These dishes are available?eggs-clusivley at?Cinnamon Soho just in time to celebrate the Easter weekend.?For ?30 per person, diners can get?egg-cited about this egg-cellent?three-course menu. Sorry, I couldn?t resist!

The Easter menu runs from Friday, 29th March to Monday, 1st April.

www.cinnamon-kitchen.com/soho-home
5 Kingly Street, London W1B 5PF
Telephone: 0207 437 1664
Email: info@cinnamonsoho.com

Opening hours: Monday to Saturday 11am ? 1 am (last food order 11pm)
Sunday 12pm-4pm

Book here

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Nearest tube: Oxford Circus and Piccadilly Circus

Square Meal

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Source: http://welovefood-itsallweeat.com/2013/03/19/cinnamon-soho-easter-menu-5-kingly-street-london-w1b-5pf/

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Ozge Karaoglu's Blog - Creative Writing With WordTamer

If you are looking for ideas to let your students build up their own stories, you may like WordTamer. This tool teaches children how to develop characters, write a plot and design the settings in a story. It teaches this,?in an interactive way,?in a carnival. You move your mouse through the carnival to try each step. My favourite one is the ?Capture a Character? where you develop your character by playing a game with the ducks. When you complete each step, you can print out what you have written or save it to your desktop. WordTamer also gives certificate to the students.

Some ideas to integrate in class:

This tool is a great way to motivate any age level to write and create their stories.

Students can use the same game on WordTamer and come up with their unique stories.

Great way to show how children can start writing their stories.

Let children create their stories, print them out and display them in class.

Teachers can create questions for the stories that the students have created.

Don?t miss the chance to visit this interactive?funfair to choose a story start and get tips with your plots, genres and characters.

Source: http://ozgekaraoglu.edublogs.org/2013/03/19/creative-writing-with-wordtamer/

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Tuesday, March 19, 2013

Solving the Pricing Puzzle ? Pricing Leadership

Today in many companies, the distribution of an Excel spreadsheet, accompanied by some stern wording around pricing compliance, often passes as a pricing enforcement strategy. In truth, that method actually invites intentional and incidental abuses in the implementation of a pricing strategy, not to mention limiting the sales team on what can be a dynamic, comprehensive and segmented price list. It doesn?t have to be a puzzle with extraneous parts that don?t fit together.

Organizations are better served by implementing a pricing strategy that takes into account customer attributes, timing and content of the opportunity. However, let?s not let these variables be determined by a remote sales rep in the field. Can you imagine if we had to rely on a person to search through an Excel spreadsheet to determine the cost of your roundtrip airfare from Houston to Chicago next month? It would be extraordinarily painful for the customer and the supplier. But today, that?s exactly what happens in millions of business-to-business transactions around the world.

Best practices for price enforcement today require that the systems most accessible by B2B sales representatives (i.e., CRM, ERP) include all of the potential attributes of a prospective customer or market segment, along with the pricing permitted based on the variables the sales rep will provide (i.e., products, volume, timing). To go one step further, best practices can also build-in acceptable ranges of pricing that may be extended to the prospect, along with automated escalation and approval processes that are initiated if the sales rep goes outside of those pre-determined price ranges.

Salesforce.com has established itself as the leader of cloud-based customer relationship management (CRM) solutions. More than 100,000 organizations use Salesforce.com to manage sales cycles and customer relationship information. This is a perfect application to enforce your pricing strategy. And here?s the best news: PROS has partnered with Salesforce.com to provide a native application that simplifies your access to specific, accurate and optimized pricing data for each of your market segments. No more searching through Excel spreadsheets or organizing meetings to determine your customized pricing based on customer size and scope of order. Your field sales team will have all of this information readily available based on scientifically proven, optimized pricing data. No need to create special meetings or forums to discuss special pricing terms. Your sales team will increase responsiveness AND profitability all at once!

To find out more, visit http://www.pros.com/solutions/sales-effectiveness/quoting-salesforce/

If you have questions, drop me a line here.

Kevin Fitzgerald

Kevin Fitzgerald joined PROS in 2012, responsible for mid-market sales. In this role, he leads the company?s mid-market go-to-market strategies, including sales, marketing and channel development. He brings to PROS more than 20 years of sales, management and business development experience. He earned an M.B.A. from Duke University and holds a B.B.A. in management accounting from Pace University.

More Posts - Website

Source: http://www.pricingleadership.com/solving-the-pricing-puzzle/

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All the laws but one (Unqualified Offerings)

Share With Friends: Share on FacebookTweet ThisPost to Google-BuzzSend on GmailPost to Linked-InSubscribe to This Feed | Rss To Twitter | Politics - Top Stories News, News Feeds and News via Feedzilla.

Source: http://news.feedzilla.com/en_us/stories/politics/top-stories/292847971?client_source=feed&format=rss

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Transistor in the fly antenna

Transistor in the fly antenna [ Back to EurekAlert! ] Public release date: 18-Mar-2013
[ | E-mail | Share Share ]

Contact: Dr. Dieter Wicher
dwicher@ice.mpg.de
49-364-157-1415
Max Planck Institute for Chemical Ecology

Insect odorant receptors regulate their own sensitivity

This press release is available in German.

Highly developed antennae containing different types of olfactory receptors allow insects to use minute amounts of odors for orientation towards resources like food, oviposition sites or mates. Scientists at the Max Planck Institute for Chemical Ecology in Jena, Germany, have now used mutant flies and for the first time provided experimental proof that the extremely sensitive olfactory system of fruit flies ? they are able to detect a few thousand odor molecules per milliliter of air, whereas humans need hundreds of millions ? is based on self-regulation of odorant receptors. Even fewer molecules below the response threshold are sufficient to amplify the sensitivity of the receptors, and binding of molecules shortly afterwards triggers the opening of an ion channel that controls the fly's reaction and flight behavior. This means that a below threshold odor stimulation increases the sensitivity of the receptor, and if a second odor pulse arrives within a certain time span, a neural response will be elicited. (PLOS ONE, March 12, 2013, DOI: 10.1371/journal.pone.0058889)

A sensitive sense of smell is vital

It is amazing how many fruit flies (Drosophila melanogaster) find their way to a rotting apple. It is known that insects are able to detect the slightest concentrations of odor molecules, especially pheromones, but also "food signals".

Dieter Wicher, Shannon Olsson, Bill Hansson and their colleagues at the Max Planck Institute for Chemical Ecology were looking for answers to the question why insects can trace odor molecules so easily and at such low concentrations in comparison to other animals. They focused their attention on odorant receptor proteins in the antenna, the insects' nose. These insect proteins are pretty young from an evolutionary perspective and their molecular constituents may be the basis for the insects' highly sensitive sense of smell.

Receptor system Or22a-Orco

Insect odorant receptors form a receptor system that consists of the actual receptor protein and an ion channel. After binding of an odor molecule, receptor protein and ion channel trigger the neural electrical response. This mechanism was recently described in the receptor system Or22a-Orco (Wicher et al., Nature 452, 2008); Sato et al., Nature 452, 2008). Apart from functioning as so-called ionotropic receptors, which enable ion flow through membranes after binding of odor molecules, odorant receptors also elicit intracellular signals. These stimulate the formation of cyclic adenosine monophosphate (cyclic AMP or cAMP), which activates an ion flow through the co-receptor Orco. The role and relevance of this weak and slow electrical current, however, was until now unclear.

Drosophila mutant Orco mut

Merid N. Getahun, a PhD student from Ethiopia, and his colleagues have conducted numerous experiments on Drosophila olfactory neurons. They injected tiny amounts of compounds that stimulate, inhibit or imitate cAMP formation directly into the sensory hairs housing olfactory sensory neurons on the fly antenna. The researchers tested the flies' responses to ethyl butyrate, which has a fruity odor similar to pineapple, and measured activity in the sensory neurons by using glass microelectrodes. As a control, they used genetically modified fruit flies where the co-receptor Orco had been inactivated. "The fact that these mutants are no more able to respond to cAMP or the inhibition/activation of the involved key enzymes, such as protein kinase C and phospholipase C, shows that the highly sensitive olfactory system in insects is regulated intracellularly by their own odorant receptors," says Dieter Wicher, the leader of the research group. The combination of odorant receptor and co-receptor Orco can be compared to a transistor, Wicher continues: A weak basic current is sufficient to release the main electric current that activates the neuron. The process can also be seen as a short-term memory situated in the insect nose. A very weak stimulus does not elicit a response when it first occurs, but if it reoccurs within a certain time span it will release the electrical response according to the principle "one time is no time, but two is a bunch." [JWK/AO]

###

Original Publication:

Merid N. Getahun, Shannon B. Olsson, Sofia Lavista-Llanos, Bill S. Hansson, Dieter Wicher: Insect odorant response sensitivity is tuned by metabotropically autoregulated olfactory receptors. PLOS ONE, March 12, 2013; DOI: 10.1371/journal.pone.0058889 http://dx.doi.org/10.1371/journal.pone.0058889


[ Back to EurekAlert! ] [ | E-mail | Share Share ]

?


AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert! system.


Transistor in the fly antenna [ Back to EurekAlert! ] Public release date: 18-Mar-2013
[ | E-mail | Share Share ]

Contact: Dr. Dieter Wicher
dwicher@ice.mpg.de
49-364-157-1415
Max Planck Institute for Chemical Ecology

Insect odorant receptors regulate their own sensitivity

This press release is available in German.

Highly developed antennae containing different types of olfactory receptors allow insects to use minute amounts of odors for orientation towards resources like food, oviposition sites or mates. Scientists at the Max Planck Institute for Chemical Ecology in Jena, Germany, have now used mutant flies and for the first time provided experimental proof that the extremely sensitive olfactory system of fruit flies ? they are able to detect a few thousand odor molecules per milliliter of air, whereas humans need hundreds of millions ? is based on self-regulation of odorant receptors. Even fewer molecules below the response threshold are sufficient to amplify the sensitivity of the receptors, and binding of molecules shortly afterwards triggers the opening of an ion channel that controls the fly's reaction and flight behavior. This means that a below threshold odor stimulation increases the sensitivity of the receptor, and if a second odor pulse arrives within a certain time span, a neural response will be elicited. (PLOS ONE, March 12, 2013, DOI: 10.1371/journal.pone.0058889)

A sensitive sense of smell is vital

It is amazing how many fruit flies (Drosophila melanogaster) find their way to a rotting apple. It is known that insects are able to detect the slightest concentrations of odor molecules, especially pheromones, but also "food signals".

Dieter Wicher, Shannon Olsson, Bill Hansson and their colleagues at the Max Planck Institute for Chemical Ecology were looking for answers to the question why insects can trace odor molecules so easily and at such low concentrations in comparison to other animals. They focused their attention on odorant receptor proteins in the antenna, the insects' nose. These insect proteins are pretty young from an evolutionary perspective and their molecular constituents may be the basis for the insects' highly sensitive sense of smell.

Receptor system Or22a-Orco

Insect odorant receptors form a receptor system that consists of the actual receptor protein and an ion channel. After binding of an odor molecule, receptor protein and ion channel trigger the neural electrical response. This mechanism was recently described in the receptor system Or22a-Orco (Wicher et al., Nature 452, 2008); Sato et al., Nature 452, 2008). Apart from functioning as so-called ionotropic receptors, which enable ion flow through membranes after binding of odor molecules, odorant receptors also elicit intracellular signals. These stimulate the formation of cyclic adenosine monophosphate (cyclic AMP or cAMP), which activates an ion flow through the co-receptor Orco. The role and relevance of this weak and slow electrical current, however, was until now unclear.

Drosophila mutant Orco mut

Merid N. Getahun, a PhD student from Ethiopia, and his colleagues have conducted numerous experiments on Drosophila olfactory neurons. They injected tiny amounts of compounds that stimulate, inhibit or imitate cAMP formation directly into the sensory hairs housing olfactory sensory neurons on the fly antenna. The researchers tested the flies' responses to ethyl butyrate, which has a fruity odor similar to pineapple, and measured activity in the sensory neurons by using glass microelectrodes. As a control, they used genetically modified fruit flies where the co-receptor Orco had been inactivated. "The fact that these mutants are no more able to respond to cAMP or the inhibition/activation of the involved key enzymes, such as protein kinase C and phospholipase C, shows that the highly sensitive olfactory system in insects is regulated intracellularly by their own odorant receptors," says Dieter Wicher, the leader of the research group. The combination of odorant receptor and co-receptor Orco can be compared to a transistor, Wicher continues: A weak basic current is sufficient to release the main electric current that activates the neuron. The process can also be seen as a short-term memory situated in the insect nose. A very weak stimulus does not elicit a response when it first occurs, but if it reoccurs within a certain time span it will release the electrical response according to the principle "one time is no time, but two is a bunch." [JWK/AO]

###

Original Publication:

Merid N. Getahun, Shannon B. Olsson, Sofia Lavista-Llanos, Bill S. Hansson, Dieter Wicher: Insect odorant response sensitivity is tuned by metabotropically autoregulated olfactory receptors. PLOS ONE, March 12, 2013; DOI: 10.1371/journal.pone.0058889 http://dx.doi.org/10.1371/journal.pone.0058889


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?


AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert! system.


Source: http://www.eurekalert.org/pub_releases/2013-03/mpif-tit031813.php

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