Monday, December 10, 2012




Using HIV to Cure a Cancer


Jeff Swensen for The New York Times
Emma Whitehead, with her mother, Kari. Last spring, Emma was near death from acute lymphoblastic leukemia but is now in remission after an experimental treatment at the Children’s Hospital of Philadelphia. More Photos »
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Published: December 9, 2012 288 Comments

PHILIPSBURG, Pa. — Emma Whitehead has been bounding around the house lately, practicing somersaults and rugby-style tumbles that make her parents wince.
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An Experimental Treatment for Leukemia

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Readers’ Comments

"As an M.D. I tend to cringe at the reaction to these articles. This treatment was a big gamble, and one worth taking, but all to often these decisions are judged by their (unpredictable) outcomes."
JW, NY
It is hard to believe, but last spring Emma, then 6, was near death from leukemia. She had relapsed twice afterchemotherapy, and doctors had run out of options.
Desperate to save her, her parents sought an experimental treatment at the Children’s Hospital of Philadelphia, one that had never before been tried in a child, or in anyone with the type of leukemia Emma had. The experiment, in April, used a disabled form of the virus that causes AIDS to reprogram Emma’s immune system genetically to kill cancer cells.
The treatment very nearly killed her. But she emerged from it cancer-free, and about seven months later is still in complete remission. She is the first child and one of the first humans ever in whom new techniques have achieved a long-sought goal — giving a patient’s own immune system the lasting ability to fight cancer.
Emma had been ill with acute lymphoblastic leukemia since 2010, when she was 5, said her parents, Kari and Tom. She is their only child.
She is among just a dozen patients with advanced leukemiato have received the experimental treatment, which was developed at the University of Pennsylvania. Similar approaches are also being tried at other centers, including the National Cancer Institute and Memorial Sloan-Kettering Cancer Center in New York.
“Our goal is to have a cure, but we can’t say that word,” said Dr. Carl June, who leads the research team at the University of Pennsylvania. He hopes the new treatment will eventually replace bone-marrow transplantation, an even more arduous, risky and expensive procedure that is now the last hope when other treatments fail in leukemia and related diseases.
Three adults with chronic leukemia treated at the University of Pennsylvania have also had complete remissions, with no signs of disease; two of them have been well for more than two years, said Dr. David Porter. Four adults improved but did not have full remissions, and one was treated too recently to evaluate. A child improved and then relapsed. In two adults, the treatment did not work at all. The Pennsylvania researchers were presenting their results on Sunday and Monday in Atlanta at a meeting of the American Society of Hematology.
Despite the mixed results, cancer experts not involved with the research say it has tremendous promise, because even in this early phase of testing it has worked in seemingly hopeless cases. “I think this is a major breakthrough,” said Dr. Ivan Borrello, a cancer expert and associate professor of medicine at the Johns Hopkins University School of Medicine.
Dr. John Wagner, the director of pediatric blood and marrow transplantation at the University of Minnesota, called the Pennsylvania results “phenomenal” and said they were “what we’ve all been working and hoping for but not seeing to this extent.”
A major drug company, Novartis, is betting on the Pennsylvania team and has committed $20 million to building a research center on the university’s campus to bring the treatment to market.
Hervé Hoppenot, the president of Novartis Oncology, called the research “fantastic” and said it had the potential — if the early results held up — to revolutionize the treatment of leukemia and related blood cancers. Researchers say the same approach, reprogramming the patient’s immune system, may also eventually be used against tumors like breast andprostate cancer.
To perform the treatment, doctors remove millions of the patient’s T-cells — a type of white blood cell — and insert new genes that enable the T-cells to kill cancer cells. The technique employs a disabled form of H.I.V. because it is very good at carrying genetic material into T-cells. The new genes program the T-cells to attack B-cells, a normal part of the immune system that turn malignant in leukemia.
The altered T-cells — called chimeric antigen receptor cells — are then dripped back into the patient’s veins, and if all goes well they multiply and start destroying the cancer.
The T-cells home in on a protein called CD-19 that is found on the surface of most B-cells, whether they are healthy or malignant.
A sign that the treatment is working is that the patient becomes terribly ill, with raging fevers and chills — a reaction that oncologists call “shake and bake,” Dr. June said. Its medical name is cytokine-release syndrome, or cytokine storm, referring to the natural chemicals that pour out of cells in the immune system as they are being activated, causing fevers and other symptoms. The storm can also flood the lungs and cause perilous drops in blood pressure — effects that nearly killed Emma.
Steroids sometimes ease the reaction, but they did not help Emma. Her temperature hit 105. She wound up on a ventilator, unconscious and swollen almost beyond recognition, surrounded by friends and family who had come to say goodbye.
But at the 11th hour, a battery of blood tests gave the researchers a clue as to what might help save Emma: her level of one of the cytokines, interleukin-6 or IL-6, had shot up a thousandfold. Doctors had never seen such a spike before and thought it might be what was making her so sick.
Dr. June knew that a drug could lower IL-6 — his daughter takes it for rheumatoid arthritis. It had never been used for a crisis like Emma’s, but there was little to lose. Her oncologist, Dr. Stephan A. Grupp, ordered the drug. The response, he said, was “amazing.”
Within hours, Emma began to stabilize. She woke up a week later, on May 2, the day she turned 7; the intensive-care staff sang “Happy Birthday.”
Since then, the research team has used the same drug, tocilizumab, in several other patients.
In patients with lasting remissions after the treatment, the altered T-cells persist in the bloodstream, though in smaller numbers than when they were fighting the disease. Some patients have had the cells for years.
Dr. Michel Sadelain, who conducts similar studies at the Sloan-Kettering Institute, said: “These T-cells are living drugs. With a pill, you take it, it’s eliminated from your body and you have to take it again.” But T-cells, he said, “could potentially be given only once, maybe only once or twice or three times.”
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Sunday, December 9, 2012



Racetrack Drugs Put Europe Off U.S. Horse Meat

By 
Published: December 8, 201

PARIS — For decades, American horses, many of them retired or damaged racehorses, have been shipped to Canada and Mexico, where it is legal to slaughter horses, and then processed and sold for consumption in Europe and beyond.
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Christinne Muschi for The New York Times
A slaughterhouse in Saint-André-Avellin, Quebec, where meat is processed for sale in Europe.
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Christophe Simon/Agence France-Presse — Getty Images
A horse meat butcher shop in France.
Lately, however, European food safety officials have notified Mexican and Canadian slaughterhouses of a growing concern: The meat of American racehorses may be too toxic to eat safely because the horses have been injected repeatedly with drugs.
Despite the fact that racehorses make up only a fraction of the trade in horse meat, the European officials have indicated that they may nonetheless require lifetime medication records for slaughter-bound horses from Canada and Mexico, and perhaps require them to be held on feedlots or some other holding area for six months before they are slaughtered.
In October, Stephan Giguere, the general manager of a major slaughterhouse in Quebec, said he turned away truckloads of horses coming from the United States because his clients were worried about potential drug issues. Mr. Giguere said he told his buyers to stay away from horses coming from American racetracks.
“We don’t want them,” he said. “It’s too risky.”
The action is just the latest indication of the troubled state of American racing and its problems with the doping of horses. Some prominent trainers have been disciplined for using legal and illegal drugs, and horses loaded with painkillers have been breaking down in arresting numbers. Congress has called for reform, and state regulators have begun imposing stricter rules.
But for pure emotional effect, the alarm raised in the international horse-meat marketplace packs a distinctive punch.
Some 138,000 horses were sent to Canada or Mexico in 2010 alone to be turned into meat for Europe and other parts of the world, according to a Government Accountability Office report. Organizations concerned about the welfare of retired racehorses have estimated that anywhere from 10 to 15 percent of the population sent for slaughter may have performed on racetracks in the United States.
“Racehorses are walking pharmacies,” said Dr. Nicholas Dodman, a veterinarian on the faculty of Tufts University and a co-author of a 2010 article that sought to raise concerns about the health risks posed by American racehorses. He said it was reckless to want any of the drugs routinely administered to horses “in your food chain.”
Horses being shipped to Mexico and Canada are by law required to have been free of certain drugs for six months before being slaughtered, and those involved in their shipping must have affidavits proving that. But European Commission officials say the affidavits are easily falsified. As a result, American racehorses often show up in Canada within weeks — sometimes days — of their leaving the racetrack and their steady diets of drugs.
In October, the European Commission’s Directorate General for Health and Consumers found serious problems while auditing the operations of equine slaughter facilities in Mexico, where 80 percent of the horses arrive from the United States. The commission’s report said Mexican officials were not allowed to question the “authenticity or reliability of the sworn statements” about the ostensibly drug-free horses, and thus had no way of verifying whether the horses were tainted by drugs.
“The systems in place for identification, the food-chain information and in particular the affidavits concerning the nontreatment for six months with certain medical substances, both for the horses imported from the U.S. as well as for the Mexican horses, are insufficient to guarantee that standards equivalent to those provided for by E.U. legislation are applied,” the report said.
The authorities in the United States and Canada acknowledge that oversight of the slaughter business is lax. On July 9, the United States Food and Drug Administration sent a warning letter to an Ohio feedlot operator who sells horses for slaughter. The operator, Ronald Andio, was reprimanded for selling a drug-tainted thoroughbred horse to a Canadian slaughterhouse.
The Canadian Food Inspection Agency had tested the carcass of the horse the previous August and found the anti-inflammatory drug phenylbutazone in the muscle and kidney tissues. It also discovered clenbuterol, a widely abused medication for breathing problems that can build muscle by mimicking anabolic steroids.
Because horses are not a traditional food source in the United States, the Food and Drug Administration does not require human food safety information as it considers what drugs can be used legally on horses. Patricia El-Hinnawy, a spokeswoman for the agency, said agency-approved drugs intended for use in horses carried the warning “Do not use in horses intended for human consumption.”
A New York Times examination of American horse racing showed an industry still mired in a culture of drugs and inadequate regulation and a fatal breakdown rate that remains far worse than in most of the world. The examination found that 24 horses died each week at America’s racetracks and that in one recent three-year period, more than 3,800 horses had positive drug tests, mostly for illegally high levels of prescription drugs.
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Friday, December 7, 2012


Science
IMMUNOLOGY

Platelets Kill the Parasite Within

  1. Michael F. Good2
+Author Affiliations
  1. 1Queensland Institute of Medical Research, Brisbane, QLD Australia.
  2. 2Institute for Glycomics, Griffith University, Gold Coast, QLD Australia.
  1. E-mail: michael.good@griffith.edu.au

The estimated 216 million cases of malaria in 2010 resulted in about 655,000 deaths, around 86% of which were children under the age of 5 (1), mainly in sub-Saharan Africa. Most of these deaths are caused by the protozoan parasite Plasmodium falciparum. Our poor understanding of innate resistance and the development of immunity to P. falciparum is an obstacle to developing vaccines and new therapeutics. The human body has numerous defenses to protect itself against severe forms of malaria. One such strategy, previously underappreciated, involves platelets—unnucleated fragments of megakaryocytes normally thought of as being critical solely to prevent hemorrhage. On page 1348 in this issue, McMorran et al. (2) reveal a mechanism by which platelets can recognize infected red blood cells and kill the parasite within (see the figure)
Destroying P. falciparum.
(A) Activated platelets containing PF4-laden granules bind to parasitized red blood cells that express the Duffy-antigen receptor. (B) Upon binding [through CD36 on platelets and a parasite receptor on the red blood cell, possibly P. falciparum erythrocyte membrane protein 1 (PfEMP-1) (15)], PF4 is released and binds to the Duffy-antigen receptor on red blood cells. (C) The PF4–Duffy-antigen receptor complex translocates into the cell, colocalizes with intracellular parasites, and then kills the parasites.
.
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NATURE NEWS BLOG

Space venture plans to ferry people to the Moon

 | Posted by Eric Hand | Category: 
GOLDEN SPIKE
In May, SpaceX rocketed up to the space station and showed that commercial cargo was possible. In the next several years, people could start riding those rockets, and commercial crew will come into being.
Next up, says Gerry Griffin, is what you might call ‘commercial Moon’. Griffin’s startup company, called Golden Spike, after the spike used to complete the first US transcontinental railroad, was unveiled on Thursday in Washington DC. The company plans to sell regular trips to the surface of the Moon for two people for about $1.4 billion — a price that Griffin thinks is within reach for many countries and corporations. “The time is ripe for commercial human lunar exploration,” says Griffin, former director of NASA’s Johnson Space Center in Houston, Texas.
More like an airline company rather than an aircraft manufacturer, Golden Spike has not committed to specific vendors who will build the various components for the mission, though Stern acknowledged that one mission formulation could rely on SpaceX rockets. The only piece that needs to be designed from scratch is the lunar lander.
It is entirely possible that those manufacturers could compete with Golden Spike. But one of those people, Elon Musk, the founder of SpaceX, has so far been more interested in going to Mars with a space capsule called Red Dragon. “He has no interest in ‘Grey Dragon’,” says Steve Mackwell, an adviser to Golden Spike and director of the Lunar and Planetary Institute in Houston, Texas.
Another issue is whether there is a big enough market. Stern says as many as 20 nations could afford the price tag, and would do it for reasons of prestige or science. Eventually, tourism might play a part. While the first mission would cost about $8 billion, the cost to Golden Spike would quickly come down upon subsequent missions. The company also plans to make money off of media rights, naming rights, and merchandising.
Mackwell says Golden Spike needs to ensure that the missions are worthwhile scientifically, otherwise the prestige in having Golden Spike do all the work is not so high. “If all you get is a taxi ride, the number of buyers will be very limited.” But Stern points out there were plenty of nations who lined up like a “stack of pancakes” to pay the Soviet Union for rides to the Salyut and Mir space stations in the 1980s and 1990s.
Golden Spike is one in a flurry of commercial space efforts underway that have been enabled in part by the cheaper access to space that companies like SpaceX could provide. In April, a company called Planetary Resources announced plans to mine asteroids. And in June, a private foundation called B612 announced plans to launch a space telescope to spot hazardous asteroids.
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Thursday, December 6, 2012

Hours After A Meal, It's The Memory That Matters
(Sarah Zielinski)


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Tuesday, December 4, 2012


NATURE | NEWS

Graphene towers promise 'flexi-electronics'

The 3D ‘monoliths’ — grown between forming ice crystals — add elasticity to the super-strength and conductivity of graphene sheets.
The graphene towers' honeycomb structure gives it super-strength and resilience.
L. QIU, MONASH UNIVERSITY
It can support 50,000 times its own weight, springs back into shape after being compressed by up to 80% and has a density much lower than most comparable metal-based materials. A new superelastic, three-dimensional form of graphene can even conduct electricity, paving the way for flexible electronics, researchers say.
The team, led by Dan Li, a materials engineer at Monash University in Clayton, Australia, coaxed 1-centimetre-high graphene blocks or 'monoliths' from tiny flakes of graphene oxide, using ice crystals as templates. The work is published today in Nature Communications1.
Graphene, a two-dimensional form of carbon that was first isolated less than a decade ago, has exceptional mechanical strength and electrical conductivity, but making use of these properties means first finding ways to scale up from nano-sized flakes (see ‘Graphene spun into metre-long fibres’).
Li and his colleagues adapted an industrial technique called freeze casting to do just that. This involves growing layers of an oxygen-coated, soluble version of graphene called graphene oxide between forming ice crystals. On cooling the aqueous solution of graphene oxide flakes, a thin layer of the nanomaterial becomes trapped between the growing crystals, forming a continuous network that retains its structure once the ice is thawed.

In the latest study, researchers show that by partially stripping the oxygen coating before freeze casting, they could enhance the bonding between adjacent flakes in the network, producing much stronger materials.Researchers have used this method before2, but the resulting material had poor mechanical strength — a property that Li attributes to the oxygen layer that coats each flake, which weakens bonding between neighbouring flakes in the network.        
After freeze casting, the honeycomb-like network held its shape as the ice was removed. The researchers could then chemically convert the graphene oxide into graphene, strengthening inter-sheet bonding, and so the material itself, still further.

Fill the void

Li attributes the new graphene's properties to its structure: the individual graphene sheets are neatly aligned, forming an ordered network of hexagonal pores.
2D graphene sheets have exceptional properties which researchers want to scale up from nano- dimensions.
THINKSTOCK
Rodney Ruoff, a researcher in graphene assemblies at the University of Texas at Austin, says that the material “is very interesting for the extremely low density that the researchers achieve, as well as its exceptional mechanics”. He adds that the structure could be used as a scaffold for flexible battery electrodes, or form the basis of many composite materials. “It would be interesting to fill the pores with rubber materials, for example,” he says. “There is a great interest in making rubber thermally or electrically conductive without harming its elastic properties.”
Li says that the superelastic graphene has potential for use in biomedical applications. “Biomaterials people are very interested in this structure because the pore sizes match existing tissue scaffolds very well,” he says
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Friday, November 30, 2012


More Drugs Cited As A Risky Mix with Grapefruit
(Helen Thompson)



http://www.npr.org/blogs/health/2012/11/27/166012281/a-deadly-cocktail-some-medications-don-t-mix-well-with-grapefruit?ft=1&f=1001
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NATURE | NEWS

Simulated brain scores top test marks

First computer model to produce complex behaviour performs almost as well as humans at simple number tasks.

Spaun solves simple tests

Spaun sees a series of digits: 1 2 3; 5 6 7; 3 4 ?. Its neurons fire, and it calculates the next logical number in the sequence. It scrawls out a 5, in legible if messy writing.
This is an unremarkable feat for a human, but Spaun is actually a simulated brain. It contains 2.5 million virtual neurons — many fewer than the 86 billion in the average human head, but enough to recognize lists of numbers, do simple arithmetic and solve reasoning problems. 
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Thursday, November 29, 2012


NATURE


  Jiangxi province, China, 2009.

REUTERS

Grim picture of polar ice-sheet loss

Antarctica and Greenland are rapidly losing their ice sheets because of climate change, says a comprehensive review.

Climate policy: The Kyoto approach has failed

Emissions trading: Cap and trade finds new energy







The global energy challenge: Awash with carbon


More than ever, nations are powering themselves from abundant supplies
of fossil fuels.
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Press Release No. 966

For use of the information media
Not an official record





GENEVA/DOHA, 28 November 2012 (WMO) – The years 2001–2011 were all among the  warmest on record, and, according to the World Meteorological Organization, the first ten months indicate that 2012 will most likely be no exception despite the cooling influence of La Niña early in the year.
WMO’s provisional annual statement on the state of the global climate also highlighted the unprecedented melt of the Arctic sea ice and multiple weather and climate extremes which affected many parts of the world. It was released today to inform negotiators at the United Nations Climate Change Conference in Doha, Qatar.
January-October 2012 has been the ninth warmest such period since records began in 1850. The global land and ocean surface temperature for the period was about 0.45°C (0.81°F) above the corresponding 1961–1990 average of 14.2°C, according to the statement.
...
“The extent of Arctic sea ice reached a new record low. The alarming rate of its melt this year highlighted the far-reaching changes taking place on Earth’s oceans and biosphere.  Climate change is taking place before our eyes and will continue to do so as a result of the concentrations of greenhouse gases in the atmosphere, which have risen constantly and again reached new records,” added Mr Jarraud.
The Arctic reached its lowest annual sea ice extent since the start of satellite records on 16 September at 3.41 million square kilometers. This was 18% less than the previous record low of 18 September, 2007. The 2012 minimum extent was 49 percent or nearly 3.3 million square kilometers (nearly the size of India) below the 1979–2000 average minimum. Some 11.83 million square kilometers of Arctic ice melted between March and September 2012.
WMO will release a 10-year report on the state of the climate, “2001-2010, A Decade of Extremes” on 4 December 2012. It was produced in partnership with other United Nations and international agencies and highlights the warming trend for the entire planet, its continents and oceans during the past decade, with an indication of its impacts on health, food security and socio-economic development.
Highlights of 2012 provisional statement
Temperatures:.
During the first ten months of 2012, above-average temperatures affected most of the globe’s land surface areas, most notably North America (warmest on record for contiguous United States of America), southern Europe, western and central Russia and northwestern Asia. Much of South America and Africa experienced above average temperatures during the first ten months of the year, with the most anomalous warmth across parts of northern Argentina and northern Africa. Much of Asia had above-average temperatures, with cooler-than-average conditions across parts of northern China. South Asia and the Pacific were also predominantly warmer than normal, except for Australia.
Extremes: Notable extreme events were observed worldwide, but some parts of the Northern Hemisphere were affected by multiple extremes during January–October 2012.
  • Heat waves: Major heat waves impacted the Northern Hemisphere during the year, with the most notable in March–May across the continental United States of America and Europe. Warm spells during March 2012 resulted in many record-breaking temperatures in Europe and nearly 15,000 new daily records across the USA. Russia witnessed the second warmest summer on record after 2010.  Numerous temperature records were broken in Morocco in summer.
  • Drought:  According to the U.S. Drought Monitor, nearly two-thirds of the continental United States (65.5 percent) was considered to be in moderate to exceptional drought on 25 September  2012. Drought conditions impacted parts of western Russia and western Siberia during June and July, and Southeast Europe, the Balkans and some Mediterranean countries during summer. In China, the Yunnan and southwestern Sichuan province experienced severe drought during winter and spring. Northern Brazil witnessed the worst drought in 50 years. The April–October precipitation total, in Australia was 31 percent below normal.
  • Floods: Many parts of western Africa and the Sahel, including Niger and Chad, suffered serious flooding between July and September because of a very active monsoon. Heavy rainfall from the end of July through early October prompted exceptional floods across Nigeria. Parts of southern China experienced their heaviest rainfall in the last 32 years in April and May. Devastating monsoonal floods impacted Pakistan during September.  Central and parts of northern Argentina suffered from record rainfall and flooding in August, and parts of Colombia were affected by heavy precipitation for most of the year.
  • Snow and Extreme Cold:  A cold spell on the Eurasian continent from late January to mid-February was notable for its intensity, duration, and impact. Across eastern Russia, temperatures ranged between -45°C to -50°C during the end of January. Several areas of eastern Europe reported minimum temperatures as low as -30°C, with some areas across northern Europe and central Russia experiencing temperatures below -40°C.
Tropical Cyclones: Global tropical cyclone activity for the first ten months was near the 1981–2010 average of 85 storms, with a total of 81 storms (wind speeds greater or equal than 34 knots, or 63 kilometers per hour).  The Atlantic basin experienced an above-average hurricane season for a third consecutive year with a total of 19 storms, with ten reaching hurricane status, the most notably being Sandy, which wreaked havoc across the Caribbean and the USA East Coast. Throughout the year, East Asia was severely impacted by powerful typhoons. Typhoon Sanba was the strongest cyclone, globally, to have formed in 2012. Sanba impacted the Philippines, Japan, and the Korean Peninsula, dumping torrential rain and triggering floods and landslides that affected thousands of people and caused millions in U.S. dollars in damage.
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The Mars rover Curiosity has found something — something noteworthy, in a pinch of Martian sand. But what is it?
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NASA/JPL-Caltech, via Malin Space Science Systems, via EPA
The Curiosity rover in a self-portrait stitched together from 55 images taken by a camera at the end of one of its arms. Data from the rover’s first soil sample is now being analyzed by scientists.
The scientists working on the mission who know are not saying. Outside of that team, lots of people are guessing.
The intrigue started last week when John P. Grotzinger, the Mars mission’s project scientist, told National Public Radio: “This data is going to be one for the history books. It’s looking really good.”
And then he declined to say anything more.
Fossils? Living microbial Martians? Maybe the carbon-based molecules known as organics, which are the building blocks of life? That so much excitement could be set off by a passing hint reflects the enduring fascination of both scientists and nonscientists with Mars.
“It could be all kinds of things,” said Peter H. Smith, a planetary scientist at the University of Arizona who was the principal investigator for NASA’s earlier Phoenix Mars mission but is not involved with Curiosity. “If it’s historic, I think it’s organics. That would be historic in my book.”
Dr. Grotzinger and other Curiosity scientists will announce their latest findings on Monday in San Francisco at a meeting of the American Geophysical Union.
Do not expect pictures of Martians, though.
Guy Webster, a spokesman for NASA’s Jet Propulsion Laboratory in Pasadena, Calif., which operates Curiosity, said the findings would be “interesting” rather than “earthshaking.”
Mr. Webster noted that “a really big announcement,” if one should occur, would most likely be made at NASA headquarters in Washington and not at an academic conference.
Whatever is revealed will be linked to the work of Curiosity’s sophisticated chemistry laboratory instrument, Sample Analysis at Mars — SAM, for short. The rover’s robotic arm dropped the first bit of sand and dust into the instrument on Nov. 9, and the scientists have been analyzing and contemplating ever since.
One of the main goals of SAM is to identify organic molecules, but it would be a big surprise for organics to show up in a first look at a sand sample selected more as a test exercise than with the expectation of a breakthrough discovery.
Curiosity will be headed toward layers of clays, which could be rich in organics and are believed to have formed during a warm and wet era early in the planet’s history. But Curiosity has months to drive before arriving at those locations.
And the Curiosity scientists have learned through experience that it pays to double-check their results before trumpeting them. An initial test of the Martian atmosphere by the same instrument showed the presence of methane, which would have been a major discovery, possibly indicating the presence of methane-generating microbes living on Mars today. But when the scientists ran the experiment again, the signs of methane disappeared, leading them to conclude that the methane found in the first test had come from air that the spacecraft had carried to Mars from its launching spot in Florida.
Mr. Webster, who was present during the interview with NPR, said Dr. Grotzinger had been talking more generally about the quality of data coming back from Curiosity and was not suggesting that the data contained a breakthrough surprise. “I don’t think he had in mind, ‘Here’s some particular chemical that’s been found,’ ” Mr. Webster said. “That’s not my impression of the conversation.”
On Twitter, Curiosity chimed in: “What did I discover on Mars? That rumors spread fast online. My team considers this whole mission ‘one for the history books.’ ” (The public information staff at the Jet Propulsion Laboratory writes the posts for the rover.)


Stores of ice confirmed on Sun-scorched Mercury

MESSENGER finds evidence of pure water ice near planet's north pole.
Water ice is abundant in Mercury's dark polar craters.
NASA/JOHNS HOPKINS UNI APPLIED PHYS LAB/CARNEGIE INST OF WASHINGTON
Talk about a land of fire and ice. The surface of Mercury is hot enough in some places to melt lead, but it is a winter wonderland at its poles — with perhaps a trillion tonnes of water ice trapped inside craters — enough to fill 20 billion Olympic skating rinks.
The ice — whose long-suspected presence1 has now been confirmed by NASA's orbiting MESSENGER probe — seems to be much purer than ice inside similar craters on Earth's Moon, suggesting that the closest planet to the Sun could be a better trap for icy materials delivered by comets and asteroids. Three papers detailing the findings are published today in Science2, 3, 4.
Despite Mercury’s blistering 400 °C temperatures, the floors of many of its polar craters are in permanent shadow, because the planet's rotational axis is perpendicular to its orbital plane, so its poles never tip towards the star. Indeed, radar pinged to the planet from Earth in the past 20 years has revealed bright regions1 near the poles consistent with metres-thick slabs of pure water ice.

Now, three different lines of evidence back the water-ice interpretation. Infrared laser pulses fired at the planet by MESSENGER's Mercury Laser Altimeter have revealed bright regions inside nine darkened craters near the planet's north pole2. These bright regions, thought to be water ice, line up perfectly with ultra-cold spots that, according to a thermal model of the planet that takes into account Mercury's topography, should never be warmer than –170 °C3.But “radar does not uniquely identify water ice,” says David Lawrence, a planetary scientist at the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland. Sulphur, for example, could have produced a similar radar signature.
A third team, using MESSENGER's Neutron Spectrometer, has spotted the telltale signature of hydrogen — which they think is locked up in water ice — in those same regions4. "Not only is water the best explanation, we do not see any other explanation that can tie all the data together," says Lawrence, lead author of the spectrometer study.
So where did the water come from? The bright icy spots identified by MESSENGER's laser are surrounded by darker terrain which receives a bit more sunlight and heat. The neutron measurements suggest that this darker area is a layer of material about 10 centimetres thick that lies on top of more ice, insulating it.

Dark materials

This darker material around the bright spots may be made up of complex hydrocarbons expelled from comet or asteroid impacts, says David Paige, a planetary scientist at the University of California, Los Angeles, and first author of  the thermal-model paper3.
Paige and his colleagues suggest that when these icy bodies slam into Mercury, their components migrate over time — by repeatedly vaporizing and precipitating — to the cooler poles, where they get stuck in the frigid polar craters.
But even there, sunlight will sometimes hit parts of the craters' interiors, vaporizing the water ice and leaving behind ‘lag deposits’ of hydrocarbons that gradually become thicker and darker as they are chemically altered by sunlight.
Small impacts should have buried the surface if the ice were a billion years old, and the MESSENGER researchers believe it might be much younger than that, perhaps 50 million years old.
"The ice deposits we are looking at are not ancient," says Paige.
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