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Wednesday, May 22, 2013
Schools Face Tough Choices As A Tornado Nears
A man salvages stuff from what left of a bedroom of his tornado devastated home on May 21, 2013 in Moore, Oklahoma. Families returned to a blasted moonscape that had been an American suburb Tuesday after a monstrous tornado tore through the outskirts of Oklahoma City, killing at least 24 people. Nine children were among the dead and entire neighborhoods vanished, with often the foundations being the only thing left of what used to be houses and cars tossed like toys and heaped in big piles. (Jewel Samad / AFP / Getty Images)
Heath Thayer, left, and his brother Derek Thayer look at Derek's tornado-ravaged pickup truck which was thrown across the street from where it was parked Tuesday, May 21, 2013, in Moore, Okla. A huge tornado roared through the Oklahoma City suburb Monday, flattening entire neighborhoods and destroying an elementary school with a direct blow as children and teachers huddled against winds. (Charlie Riedel / AP)
Zac Woodcock salvages items from the rubble of a tornado-ravaged rental home which they own Tuesday, May 21, 2013, in Moore, Okla. A huge tornado roared through the Oklahoma City suburb Monday, flattening an entire neighborhoods and destroying an elementary school with a direct blow as children and teachers huddled against winds. (Charlie Riedel / AP)
Volunteers from Mercy Chefs prepare food for tornado victims on May 21, 2013 in Moore, Oklahoma. Families returned to a blasted moonscape that had been an American suburb Tuesday after a monstrous tornado tore through the outskirts of Oklahoma City, killing at least 24 people. Nine children were among the dead and entire neighborhoods vanished, with often the foundations being the only thing left of what used to be houses and cars tossed like toys and heaped in big piles. (Jewel Samad / AFP / Getty Images)
A Harley Davidson motorcycle is salvaged from rubble after a powerful tornado ripped through the neighborhood on May 21, 2013 in Moore, Oklahoma. The town reported a tornado of at least EF4 strength and two miles wide that touched down yesterday killing at least 24 people and leveling everything in its path. U.S. President Barack Obama promised federal aid to supplement state and local recovery efforts. (Scott Olson / Getty Images)
Curtis Cook recovers his high school football photo from the rubble of his family's house after a powerful tornado ripped through the area destroying his home on May 21, 2013 in Moore, Oklahoma. The photo was also recovered after his parent's home was destroyed is a in a tornado in 1999. The town reported a tornado of at least EF4 strength and two miles wide that touched down yesterday killing at least 24 people and leveling everything in its path. U.S. President Barack Obama promised federal aid to supplement state and local recovery efforts. (Scott Olson / Getty Images)
Chris Combs and her husband Jimmy look over damge at Briarwood Elementary School after a powerful tornado ripped through the area on May 21, 2013 in Moore, Oklahoma. Chris is a secretary at the school and was inside the school office when the tornado hit. The town reported a tornado of at least EF4 strength and two miles wide that touched down yesterday killing at least 24 people and leveling everything in its path. U.S. President Barack Obama promised federal aid to supplement state and local recovery efforts. (Scott Olson / Getty Images)
A lifeless horse lays tangled in power lines in Moore, Okla., on Tuesday, May 21, 2013. A huge tornado roared through the Oklahoma City suburb Monday, flattening entire neighborhoods and destroying an elementary school with a direct blow as children and teachers huddled against winds. (Alonzo Adams / AP)
Joe Curry, left, and his friend search for his wife's purse in the damaged remains of his home in Moore, Okla., on Tuesday, May 21, 2013. A huge tornado roared through the Oklahoma City suburb Monday, flattening entire neighborhoods and destroying an elementary school with a direct blow as children and teachers huddled against winds. (Alonzo Adams / AP)
Tornado survivor Fred Galarza lies in his hospital bed as his wife Julie Galarza looks on in the emergency room at Integris Southwest Medical Center in Oklahoma City, Tuesday, May 21, 2013. Fred was rescued after being buried in the rubble of his Nick's Liquor Store in Moore, Ola., that was attached to the Seven Eleven where three people were killed. (Paul B. Southerland / The Oklahoman / AP)
Scott Perdue, left, yells to his parents, Gene and Colleen Perdue, not pictured, that he has located his father's 1957 Chevy in what remains of their barn as his brother-in-law Jeff Teel takes a photo at the home of Gene and Colleen Perdue, 1409 SW 149th, in Oklahoma City, on Tuesday, May 21, 2013, after a tornado struck south Oklahoma City and Moore, Okla., on Monday. (Nate Billings / The Oklahoman / AP)
Jon Johnson, left, looks through what is remains of his home at 14716 S. Broadway with his brother Matt Johnson on Tuesday, May 21, 2013, after a tornado struck south Oklahoma City and Moore, Okla., on Monday. (Nate Billings / The Oklahoman / AP)
This photo taken Tuesday, May 21, 2013 shows damage caused by Monday's tornado in the area near 4th and Bryant in Moore, Okla. (Chris Landsberger / The Oklahoman / AP)
A man who asked not to be identified hangs an American flag on what is left of a tree in a neighborhood north of SW 149th between Western and Santa Fe on Tuesday, May 21, 2013, after a tornado struck south Oklahoma City and Moore, Okla., on Monday. (Nate Billings / The Oklahoman / AP)
Michelle Kelley peers into her friend's tornado-ravaged car Tuesday, May 21, 2013, in Moore, Okla. A huge tornado roared through the Oklahoma City suburb Monday, flattening entire neighborhoods and destroying an elementary school with a direct blow as children and teachers huddled against winds. (Charlie Riedel / AP
A home in Moore, Okla. sits severely damaged Tuesday, May 21, 2013, after Monday's massive tornado moved through the area. The huge tornado roared through the Oklahoma City suburb Monday, flattening entire neighborhoods and destroying an elementary school with a direct blow as children and teachers huddled against winds. (Alonzo Adams / AP)
A tornado victim family take a break from cleaning debris from their devastated home to eat dinner late evening on May 21, 2013 in Moore, Oklahoma. Families returned to a blasted moonscape that had been an American suburb Tuesday after a monstrous tornado tore through the outskirts of Oklahoma City, killing at least 24 people. Nine children were among the dead and entire neighborhoods vanished, with often the foundations being the only thing left of what used to be houses and cars tossed like toys and heaped in big piles. (Jewel Samad / AFP / Getty Images)
A woman and young boy walk along a street as they view destroyed house on May 21, 2013 in Moore, Oklahoma. Families returned to a blasted moonscape that had been an American suburb Tuesday after a monstrous tornado tore through the outskirts of Oklahoma City, killing at least 24 people. Nine children were among the dead and entire neighborhoods vanished, with often the foundations being the only thing left of what used to be houses and cars tossed like toys and heaped in big piles. (Joshua Lott / AFP / Getty Images)
Tornado devastated houses are seen on May 21, 2013 in Moore, Oklahoma. Families returned to a blasted moonscape that had been an American suburb Tuesday after a monstrous tornado tore through the outskirts of Oklahoma City, killing at least 24 people. Nine children were among the dead and entire neighborhoods vanished, with often the foundations being the only thing left of what used to be houses and cars tossed like toys and heaped in big piles. (Jewel Samad / AFP / Getty Images)
Sean Xuereb recovers a dog from the rubble of a home that was destroyed by a tornado on May 21, 2013 in Moore, Oklahoma. The town reported a tornado of at least EF4 strength and two miles wide that touched down yesterday killing at least 24 people and leveling everything in its path. U.S. President Barack Obama promised federal aid to supplement state and local recovery efforts. (Scott Olson / Getty Images)
Roger Graham sits in front of his destroyed home after a powerful tornado ripped through the area on May 21, 2013 in Moore, Oklahoma. The town reported a tornado of at least EF4 strength and two miles wide that touched down yesterday killing at least 24 people and leveling everything in its path. U.S. President Barack Obama promised federal aid to supplement state and local recovery efforts. (Scott Olson / Getty Images)
Residents search through rubble after a powerful tornado ripped through the area on May 21, 2013 in Moore, Oklahoma. The town reported a tornado of at least EF4 strength and two miles wide that touched down yesterday killing at least 24 people and leveling everything in its path. U.S. President Barack Obama promised federal aid to supplement state and local recovery efforts. (Scott Olson / Getty Images)
Insulation hangs from the rafters of a liquor store destroyed by yesterday's tornado on May 21, 2013 in Moore, Oklahoma. The town reported a tornado of at least EF4 strength and two miles wide that touched down yesterday killing at least 24 people and leveling everything in its path. U.S. President Barack Obama promised federal aid to supplement state and local recovery efforts. (Brett Deering / Getty Images)
Bonnie Lolofie (L) and Ashley Do walk from their apartment that has no power or water but was otherwise undamaged by yesterday's tornado on May 21, 2013 in Moore, Oklahoma. The town reported a tornado of at least EF4 strength and two miles wide that touched down yesterday killing at least 24 people and leveling everything in its path. U.S. President Barack Obama promised federal aid to supplement state and local recovery efforts. (Brett Deering / Getty Images)
Men walk at their backyard of their tornado devastated neighbourhood on May 21, 2013 in Moore, Oklahoma. Families returned to a blasted moonscape that had been an American suburb Tuesday after a monstrous tornado tore through the outskirts of Oklahoma City, killing at least 24 people. Nine children were among the dead and entire neighborhoods vanished, with often the foundations being the only thing left of what used to be houses and cars tossed like toys and heaped in big piles. (Jewel Samad / AFP / Getty Images)
A woman salvages memorable from her tornado devastated home on May 21, 2013 in Moore, Oklahoma. Families returned to a blasted moonscape that had been an American suburb Tuesday after a monstrous tornado tore through the outskirts of Oklahoma City, killing at least 24 people. Nine children were among the dead and entire neighborhoods vanished, with often the foundations being the only thing left of what used to be houses and cars tossed like toys and heaped in big piles. (Jewel Samad / AFP / Getty Images
A resident moves some of his belongings from his destroyed home on May 21, 2013 in Moore, Oklahoma. Families returned to a blasted moonscape that had been an American suburb Tuesday after a monstrous tornado tore through the outskirts of Oklahoma City, killing at least 24 people. Nine children were among the dead and entire neighborhoods vanished, with often the foundations being the only thing left of what used to be houses and cars tossed like toys and heaped in big piles. (Joshua Lott / AFP / Getty Images)
A destroyed police car is seen on May 21, 2013 in Moore, Oklahoma. Families returned to a blasted moonscape that had been an American suburb Tuesday after a monstrous tornado tore through the outskirts of Oklahoma City, killing at least 24 people. Nine children were among the dead and entire neighborhoods vanished, with often the foundations being the only thing left of what used to be houses and cars tossed like toys and heaped in big piles. (Joshua Lott / AFP / Getty Images)
Rodney Heltcel, left, salvages the wreckage of his home for photos and irreplaceable items, such as the print of his grandchildren he placed at right, a day after a tornado moved through Moore, Okla., Tuesday, May 21, 2013. The huge tornado roared through the Oklahoma City suburb, flattening entire neighborhoods and destroying an elementary school with a direct blow as children and teachers huddled against winds. (Brennan Linsley / AP)
Kandi Scott salvages items from the rubble of her home, which she shared with her mother, until it was destroyed Monday when a tornado moved through Moore, Okla., Tuesday, May 21, 2013. The huge tornado roared through the Oklahoma City suburb, flattening entire neighborhoods and destroying an elementary school with a direct blow as children and teachers huddled against winds.(AP Photo/Brennan Linsley)
A soldier walks past the wreckage left when a tornado moved through Moore, Okla., Tuesday, May 21, 2013. The huge tornado roared through the Oklahoma City suburb, flattening entire neighborhoods and destroying an elementary school with a direct blow as children and teachers huddled against winds.(AP Photo/Brennan Linsley)
The medical center in Moore, Okla. sustained serious damage during Monday's tornado.
The powerful tornado that swept through Moore, Okla. on Monday leveled homes and businesses, while also destroying much of the natural landscape. This photo shows trees stripped of their bark by the extreme winds.
Hundreds of cars were destroyed by Monday's tornado as it swept through Moore, Okla.
Justin Stehan salvages photographs from his tornado-ravaged home Tuesday, May 21, 2013, in Moore, Okla. A huge tornado roared through the Oklahoma City suburb Monday, flattening entire neighborhoods and destroying an elementary school with a direct blow as children and teachers huddled against winds. (AP Photo/Charlie Riedel)
An unidentified man watches a rain storm from inside the garage of his tornado-damaged home Tuesday, May 21, 2013, in Moore, Okla. A huge tornado roared through the Oklahoma City suburb Monday, flattening entire neighborhoods and destroying an elementary school with a direct blow as children and teachers huddled against winds. (AP Photo/Charlie Riedel)
Victor Gonzalez seeks shelter from the rain under a sheet of plastic as he helps a friend salvage items from a tornado-ravaged home Tuesday, May 21, 2013, in Moore, Okla. A huge tornado roared through the Oklahoma City suburb Monday, flattening entire neighborhoods and destroying an elementary school with a direct blow as children and teachers huddled against winds. (AP Photo/Charlie Riedel)
Jim Stubblefield, of Norman, Okla., raises a tattered flag he found while helping his sister salvage items from her tornado-ravaged home Tuesday, May 21, 2013, in Moore, Okla. A huge tornado roared through the Oklahoma City suburb Monday, flattening entire neighborhoods and destroying an elementary school with a direct blow as children and teachers huddled against winds. (AP Photo/Charlie Riedel)
An aerial view shows an entire neighborhood destroyed by Monday's tornado, Tuesday, May 21, 2013, in Moore, Okla. At least 24 people, including nine children, were killed in the massive tornado that flattened homes and a school in Moore, on Monday afternoon. (AP Photo/Tony Gutierrez)
An aerial view of homes damaged by Monday's tornado Tuesday, May 21, 2013, in Moore, Okla.At least 24 people, including nine children, were killed in the massive tornado that flattened homes and a school in Moore, on Monday afternoon. (AP Photo/Tony Gutierrez)
Austin Brock holds cat Tutti, shortly after the animal was retrieved from the rubble of Brock's home, which was demolished a day earlier when a tornado moved through Moore, Okla., Tuesday, May 21, 2013. A huge tornado roared through the Oklahoma City suburb Monday, flattening an entire neighborhoods and destroying an elementary school with a direct blow as children and teachers huddled against winds. (AP Photo/Brennan Linsley)
An aerial view shows homes damaged by Monday's tornado as others appear untouched, Tuesday, May 21, 2013, in Moore, Okla. At least 24 people, including nine children, were killed in the massive tornado that flattened homes and a school in Moore, on Monday afternoon. (AP Photo/Tony Gutierrez)
An aerial view of a street lined by homes destroyed by Monday's tornado is shown Tuesday, May 21, 2013, in Moore, Okla. At least 24 people, including nine children, were killed in the massive tornado that flattened homes and a school in Moore, on Monday afternoon. (AP Photo/Tony Gutierrez)
An aerial view of an entire neighborhood destroyed by Monday's tornado is shown Tuesday, May 21, 2013, in Moore, Okla. At least 24 people, including nine children, were killed in the massive tornado that flattened homes and a school in Moore, on Monday afternoon. (AP Photo/Tony Gutierrez)
Damaged vehicles from Monday's tornado can be seen in the parking lot of the Moore Medical Center Tuesday, May 21, 2013, in Moore, Oklahoma. A huge tornado roared through the Oklahoma City suburb Monday, flattening an entire neighborhoods and destroying an elementary school with a direct blow as children and teachers huddled against winds. (AP Photo/Tony Gutierrez)
A man stands on the roof of a destroyed home on May 21, 2013 in Moore, Oklahoma. Families returned to a blasted moonscape that had been an American suburb Tuesday after a monstrous tornado tore through the outskirts of Oklahoma City, killing at least 24 people. Nine children were among the dead and entire neighborhoods vanished, with often the foundations being the only thing left of what used to be houses and cars tossed like toys and heaped in big piles. (Joshua Lott / AFP /Getty Images)
Lea Bessinger and her son Josh Bessinger look through the rubble of the elder Bessinger's tornado-ravaged home Tuesday, May 21, 2013, in Moore, Okla. A huge tornado roared through the Oklahoma City suburb Monday, flattening an entire neighborhoods and destroying an elementary school with a direct blow as children and teachers huddled against winds. (AP Photo/Charlie Riedel)
Zac Woodcock salvages items from the rubble of a tornado-ravaged rental home which they own Tuesday, May 21, 2013, in Moore, Okla. A huge tornado roared through the Oklahoma City suburb Monday, flattening an entire neighborhoods and destroying an elementary school with a direct blow as children and teachers huddled against winds. (AP Photo/Charlie Riedel)
A destroyed police car sits among the debris of tornado-ravaged homes Tuesday, May 21, 2013, in Moore, Okla. A huge tornado roared through the Oklahoma City suburb Monday, flattening an entire neighborhoods and destroying an elementary school with a direct blow as children and teachers huddled against winds. (AP Photo/Charlie Riedel)
A concrete angel rests on a destropyed car in a tornado-ravaged neighborhood Tuesday, May 21, 2013, in Moore, Okla. A huge tornado roared through the Oklahoma City suburb Monday, flattening entire neighborhoods and destroying an elementary school with a direct blow as children and teachers huddled against winds. (AP Photo/Charlie Riedel)
Zac and Denisha Woodcock look through the rubble of a tornado-ravaged rental home which they own Tuesday, May 21, 2013, in Moore, Okla. A huge tornado roared through the Oklahoma City suburb Monday, flattening an entire neighborhoods and destroying an elementary school with a direct blow as children and teachers huddled against winds. (AP Photo/Charlie Riedel)
Source: http://www.huffingtonpost.com/2013/05/21/schools-tornado_n_3315235.html
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Tuesday, May 21, 2013
Deadly Moore Tornado Tops the Scale at EF-5
Complete and utter destruction in some parts of Moore, Okla., in the wake of yesterday's deadly tornado confirms the twister was a rare EF-5 ? the top of the tornado rating scale, the National Weather Service announced today (May 21).
Storm survey crews reached the hardest-hit neighborhoods of Moore this afternoon as lightning and hail continued to batter the devastated city. The survey process is subjective, but team members rely on a checklist of 28 tornado damage indicators to estimate wind speeds and the degree of damage.
The National Weather Service's (NWS) four survey teams also found several areas of damage rated as EF-4 along the tornado?s path, according to the Facebook page of the NWS office in Norman, Okla. The preliminary ranking could still be revised in the coming days, as crews continue to assess the damage.
Tornadoes are ranked on the Enhanced Fujita Scale. An EF-0 rating is reserved for minor damage, and an EF-5 is considered the most severe, with winds topping 200 mph (322 km/h).
The Moore tornado excavated a path up to 1.3 miles (2 kilometers) wide along a 17-mile-long (27 km) stretch of central Oklahoma, the NWS said. The twister touched down 4.4 miles (7.1 km) east of Newcastle at 2:45 p.m. CDT and ended 4.8 miles (7.7 km) east of Moore, a southern suburb of Oklahoma City, at 3:35 p.m. CDT. [Image Gallery: Moore Tornado]
At first, the tornado caused little damage on the ground. But the storm ramped up quickly, intensifying to EF-4 levels in about 10 minutes and in just about 4 miles (6.4 km), the NWS said. The storm produced EF-4 scale damage, with winds of up to 200 mph (322 km/h) by Interstate 44 near Moore.
There have been 58 F5 or EF-5 tornadoes in the United States since 1950, according to the NWS. The rating scale was updated in 2007 to more closely align wind speeds with storm damage.
The United States has more than 1,000 tornadoes every year, and only 1 percent of those ever reach EF-5 strength, according to the National Climatic Data Center.
"In any given year, you will have maybe a dozen EF-4s and maybe one EF-5," said Bob Henson, a meteorologist and science writer for the National Center for Atmospheric Research in Boulder, Colo.
Email Becky Oskin or follow her @beckyoskin. Follow us?@OAPlanet, Facebook?& Google+. Original article on LiveScience's OurAmazingPlanet.
Copyright 2013 LiveScience, a TechMediaNetwork company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.Source: http://news.yahoo.com/deadly-moore-tornado-tops-scale-ef-5-213001028.html
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Are we on the cusp of a solar energy boom?
Solar power is getting much easier to store ? and at a much cheaper price
The total solar energy hitting the Earth each year is equivalent to 12.2 trillion watt-hours. That's over 20,000 times more than the total energy all of humanity consumes each year.
And yet photovoltaic solar panels, the instruments that convert solar radiation into electricity, produce only 0.7 percent of the energy the world uses.
SEE MORE: The politics behind Kanye West's 'New Slaves'
So what gives?
For one, cost: The U.S. Department of Energy estimates an average cost of $156.90 per megawatt-hour for solar, while conventional coal costs an average of $99.60 per MW/h, nuclear costs an average of $112.70 per MW/h, and various forms of natural gas cost between $65.50 and $132 per MW/h. So from an economic standpoint, solar is still uncompetitive.
SEE MORE: WATCH: Jon Stewart hates everyone in Washington now
And from a technical standpoint, solar is still tough to store. "A major conundrum with solar panels has always been how to keep the lights on when the sun isn't shining," says Christoph Steitz and Stephen Jewkes at Reuters.
But thanks to huge advancements, solar's cost and technology problems are increasingly closer to being solved.
SEE MORE: Oklahoma City's ferocious tornado: What you should know
(Bloomberg & New Energy Finance)
If the trend stays on track for another 8-10 years, solar generated electricity in the U.S. would descend to a level of $120 per MW/h ? competitive with coal and nuclear ? by 2020, or even 2015 for the sunniest parts of America. If prices continue to fall over the next 20 years, solar costs would be half that of coal (and have the added benefits of zero carbon emissions, zero mining costs, and zero scarcity).
SEE MORE: WATCH: Live coverage of the Oklahoma City tornado
Scientists have made huge advances in thermal storage as well, finding vastly more efficient ways to store solar energy. (In one example, solar energy is captured and then stored in beds of packed rocks.)
Lower costs and better storage capacity would mean cheap, decentralized, plentiful, sustainable energy production ? and massive relief to global markets that have been squeezed in recent years by the rising cost of fossil fuel extraction, a burden passed on to the consumer. All else being equal, falling energy prices mean more disposable income to save and invest, or to spend.
SEE MORE: Angry at the government? 5 ways you can fight back
The prospect of widespread falling energy costs could be a basis for a period of strong economic growth. It could help us replace our dependence on foreign oil with a robust, decentralized electric grid, where energy is generated closer to the point of use. This would mean a sustainable energy supercycle ? and new growth in other industries that benefit from falling energy costs.
Indeed, a solar boom could prove wrong those who claim that humanity has over-extended itself and that the era of growth is over.
SEE MORE: Are journalists above the law?
View this article on TheWeek.com Get 4 Free Issues of The Week
Other stories from this section:
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Gas prices rise slightly in New Hampshire
CONCORD, N.H. (AP) -- Gas prices have risen in New Hampshire, but they're still below the national average.
The website Gasbuddy.com says the average retail price for a gallon of gas rose 1.9 cents in the last week, averaging $3.45 in New Hampshire on Sunday.
Prices were 23.9 cents per gallon lower than the same day a year ago and are 2.8 cents per gallon higher than a month ago.
The national average increased 8.9 cents per gallon in the last week, to $3.67. The price has increased 16.6 cents per gallon during the last month and stands 3 cents per gallon lower than a year ago.
Prices have been climbing steadily in the Midwest, said GasBuddy.com Senior Petroleum Analyst Patrick DeHaan.
"I don't believe I've ever seen gasoline prices in the Midwest surpass California ? areas of Nebraska, Minnesota, Oklahoma, North and South Dakota, and Kansas- have done that," he said. "Gas price records in these areas aren't being quietly replaced, they're being blown out of the water. I don't believe I've ever seen such crazy trends in gasoline prices occur all at one- prices spiking in one area, falling in another, and holding steady in others. What we're seeing today is certainly rare."
Source: http://news.yahoo.com/gas-prices-rise-slightly-hampshire-165824036.html
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Timing of cancer radiation therapy may minimize hair loss, researchers say
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Public release date: 20-May-2013[ | E-mail |
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Salk Institute
Discovery of circadian clock in mice hair reveals period of time when damage from radiotherapy can be quickly repaired, keeping hair intact
LA JOLLA, CA---Discovering that mouse hair has a circadian clock - a 24-hour cycle of growth followed by restorative repair - researchers suspect that hair loss in humans from toxic cancer radiotherapy and chemotherapy might be minimized if these treatments are given late in the day.
The study, which appears in the early online edition of the Proceedings of the National Academy of Sciences (PNAS), found that mice lost 85 percent of their hair if they received radiation therapy in the morning, compared to a 17 percent loss when treatment occurred in the evening.
The researchers, from Salk Institute for Biological Studies, the University of Southern California (USC) and the University of California, Irvine (UCI), worked out the precise timing of the hair circadian clock, and also uncovered the biology behind the clockwork - the molecules that tells hair when to grow and when to repair damage. They then tested the clock using radiotherapy.
"These findings are particularly exciting because they present a significant step towards developing new radiation therapy protocols that include minimizing negative side effects on normal tissues, such as hair or bone marrow, while maintaining the desired effects on cancer cells," says Maksim Plikus, assistant professor of developmental and cell biology at UCI and the study's first author. "We will now apply our findings to design novel circadian rhythm-based approaches to cancer therapy."
The scientists can't say their findings will directly translate to human cancer therapy because they haven't yet studied that possibility. But they say it is becoming increasingly clear that body organs and tissues have their own circadian clocks that, when understood, could be used to time drug therapy for maximum benefit.
"There are clocks everywhere in the body - clocks that have their own unique rhythm that, we found, have little to do with the central clock in our brains," says the study's co-lead investigator, Satchidananda Panda, an associate professor in Salk's Regulatory Biology Laboratory and an expert on circadian rhythm.
"This suggests that delivering a drug to an organ while it is largely inactive is not a good idea. You could do more damage to the organ than when it is awake, repairing and restoring itself," says Panda. "If you know when an organ is mending itself, you might be able to deliver more potent doses of a drug or therapy. That might offer a better outcome while minimizing side effects."
Panda uses genetic, genomics and biochemical approaches to identify genes under circadian regulation in different organs and to understand the mechanism of such regulation. Plikus at UCI and Cheng-Ming Chuong, professor of pathology at the Keck School of Medicine of USC and the study's co-lead investigator, are experts on hair regeneration.
These researchers and their colleagues teamed together to find and then take apart the mouse hair circadian clock. It was a long and difficult study, Chuong says.
"Hair is a very complicated organ, featuring different types of cells going through different stages in the life cycle in a very tiny space," Chuong says. "We found that hair in mice grows fast in the morning and slows down at night, engaging a very powerful clock."
Every time hair cells divide, they pick up DNA damage that needs to be repaired. The scientists discovered that mice hair cells repair that damage primarily in the evening. This process is akin to using a kitchen dishwasher, Panda says.
"Most of us run the dishwasher after we have accumulated a lot of dirty dishes - we don't run it every time a dish is dirty. The same is true for cells. They clean up - repair their DNA - at one time each day," Panda says.
Radiotherapy damages DNA in cells that divide rapidly, which is why it is used against growing cancer cells. That means that DNA damage to hair cells from radiotherapy delivered in the morning is not repaired until the evening, leading to hair loss. Damage from radiotherapy at night, however, is minimized because hair cells, already in the process of repairing DNA, can quickly heal.
"While we don't yet know if human hair follows that same clock we found in mice hair, it is true that facial hair in men grows during the day, resulting in the proverbial 5 o'clock shadow. There is no 5 a.m. shadow if you shave at night," Panda says.
The researchers found that cancer cells do not have circadian clocks, because they are dividing all the time.
"That means cancer therapy does not have to be timed to be more effective," Panda adds. "The timing has to do with minimizing collateral damage from normal cells affected by these treatments."
Scientists know for certain that other organs, such as the liver, use a circadian clock, and they suspect that all human tissue is similarly regulated, although the clocks may be timed differently.
"There are many clinical implications for this cacophony of internal clocks, beyond the timing of drug therapy," Panda says. "For example, some researchers suspect that obesity and diabetes occurs when an organ or organs - perhaps the liver or stomach or pancreas - should be sleeping, but is awoken by food that needs to be processed.
"These local clocks do a lot more things than the central clock in the brain, which primarily regulates sleeping," he says. "This field of research is exciting and may, someday, contribute to human health."
###
Other contributing authors are Christopher Vollmers and Amandine Chaix from Salk, Damon de la Cruz from USC, and Raul Ramos from UCI.
The study was supported by grants from the National Institutes of Health (AR 42177, AR47364, DK091618, P30 CA014195), The Leona M. and Harry B. Helmsley Charitable Trust, the Dana Foundation, the Glenn Foundation for Medical Research and the Edward Mallinckrodt Jr. Foundation. The authors declare no conflicts of interest.
About the Salk Institute for Biological Studies:
The Salk Institute for Biological Studies is one of the world's preeminent basic research institutions, where internationally renowned faculty probe fundamental life science questions in a unique, collaborative, and creative environment. Focused both on discovery and on mentoring future generations of researchers, Salk scientists make groundbreaking contributions to our understanding of cancer, aging, Alzheimer's, diabetes and infectious diseases by studying neuroscience, genetics, cell and plant biology, and related disciplines.
Faculty achievements have been recognized with numerous honors, including Nobel Prizes and memberships in the National Academy of Sciences. Founded in 1960 by polio vaccine pioneer Jonas Salk, M.D., the Institute is an independent nonprofit organization and architectural landmark.
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Public release date: 20-May-2013[ | E-mail |
Share ] Contact: Andy Hoang
ahoang@salk.edu
619-861-5811
Salk Institute
Discovery of circadian clock in mice hair reveals period of time when damage from radiotherapy can be quickly repaired, keeping hair intact
LA JOLLA, CA---Discovering that mouse hair has a circadian clock - a 24-hour cycle of growth followed by restorative repair - researchers suspect that hair loss in humans from toxic cancer radiotherapy and chemotherapy might be minimized if these treatments are given late in the day.
The study, which appears in the early online edition of the Proceedings of the National Academy of Sciences (PNAS), found that mice lost 85 percent of their hair if they received radiation therapy in the morning, compared to a 17 percent loss when treatment occurred in the evening.
The researchers, from Salk Institute for Biological Studies, the University of Southern California (USC) and the University of California, Irvine (UCI), worked out the precise timing of the hair circadian clock, and also uncovered the biology behind the clockwork - the molecules that tells hair when to grow and when to repair damage. They then tested the clock using radiotherapy.
"These findings are particularly exciting because they present a significant step towards developing new radiation therapy protocols that include minimizing negative side effects on normal tissues, such as hair or bone marrow, while maintaining the desired effects on cancer cells," says Maksim Plikus, assistant professor of developmental and cell biology at UCI and the study's first author. "We will now apply our findings to design novel circadian rhythm-based approaches to cancer therapy."
The scientists can't say their findings will directly translate to human cancer therapy because they haven't yet studied that possibility. But they say it is becoming increasingly clear that body organs and tissues have their own circadian clocks that, when understood, could be used to time drug therapy for maximum benefit.
"There are clocks everywhere in the body - clocks that have their own unique rhythm that, we found, have little to do with the central clock in our brains," says the study's co-lead investigator, Satchidananda Panda, an associate professor in Salk's Regulatory Biology Laboratory and an expert on circadian rhythm.
"This suggests that delivering a drug to an organ while it is largely inactive is not a good idea. You could do more damage to the organ than when it is awake, repairing and restoring itself," says Panda. "If you know when an organ is mending itself, you might be able to deliver more potent doses of a drug or therapy. That might offer a better outcome while minimizing side effects."
Panda uses genetic, genomics and biochemical approaches to identify genes under circadian regulation in different organs and to understand the mechanism of such regulation. Plikus at UCI and Cheng-Ming Chuong, professor of pathology at the Keck School of Medicine of USC and the study's co-lead investigator, are experts on hair regeneration.
These researchers and their colleagues teamed together to find and then take apart the mouse hair circadian clock. It was a long and difficult study, Chuong says.
"Hair is a very complicated organ, featuring different types of cells going through different stages in the life cycle in a very tiny space," Chuong says. "We found that hair in mice grows fast in the morning and slows down at night, engaging a very powerful clock."
Every time hair cells divide, they pick up DNA damage that needs to be repaired. The scientists discovered that mice hair cells repair that damage primarily in the evening. This process is akin to using a kitchen dishwasher, Panda says.
"Most of us run the dishwasher after we have accumulated a lot of dirty dishes - we don't run it every time a dish is dirty. The same is true for cells. They clean up - repair their DNA - at one time each day," Panda says.
Radiotherapy damages DNA in cells that divide rapidly, which is why it is used against growing cancer cells. That means that DNA damage to hair cells from radiotherapy delivered in the morning is not repaired until the evening, leading to hair loss. Damage from radiotherapy at night, however, is minimized because hair cells, already in the process of repairing DNA, can quickly heal.
"While we don't yet know if human hair follows that same clock we found in mice hair, it is true that facial hair in men grows during the day, resulting in the proverbial 5 o'clock shadow. There is no 5 a.m. shadow if you shave at night," Panda says.
The researchers found that cancer cells do not have circadian clocks, because they are dividing all the time.
"That means cancer therapy does not have to be timed to be more effective," Panda adds. "The timing has to do with minimizing collateral damage from normal cells affected by these treatments."
Scientists know for certain that other organs, such as the liver, use a circadian clock, and they suspect that all human tissue is similarly regulated, although the clocks may be timed differently.
"There are many clinical implications for this cacophony of internal clocks, beyond the timing of drug therapy," Panda says. "For example, some researchers suspect that obesity and diabetes occurs when an organ or organs - perhaps the liver or stomach or pancreas - should be sleeping, but is awoken by food that needs to be processed.
"These local clocks do a lot more things than the central clock in the brain, which primarily regulates sleeping," he says. "This field of research is exciting and may, someday, contribute to human health."
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Other contributing authors are Christopher Vollmers and Amandine Chaix from Salk, Damon de la Cruz from USC, and Raul Ramos from UCI.
The study was supported by grants from the National Institutes of Health (AR 42177, AR47364, DK091618, P30 CA014195), The Leona M. and Harry B. Helmsley Charitable Trust, the Dana Foundation, the Glenn Foundation for Medical Research and the Edward Mallinckrodt Jr. Foundation. The authors declare no conflicts of interest.
About the Salk Institute for Biological Studies:
The Salk Institute for Biological Studies is one of the world's preeminent basic research institutions, where internationally renowned faculty probe fundamental life science questions in a unique, collaborative, and creative environment. Focused both on discovery and on mentoring future generations of researchers, Salk scientists make groundbreaking contributions to our understanding of cancer, aging, Alzheimer's, diabetes and infectious diseases by studying neuroscience, genetics, cell and plant biology, and related disciplines.
Faculty achievements have been recognized with numerous honors, including Nobel Prizes and memberships in the National Academy of Sciences. Founded in 1960 by polio vaccine pioneer Jonas Salk, M.D., the Institute is an independent nonprofit organization and architectural landmark.
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Source: http://www.eurekalert.org/pub_releases/2013-05/si-t052013.php
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