Saturday, February 17, 2018

Shriveling Storm on Neptune

Hubble Sees Neptune's Mysterious Shrinking Storm

NASA – February 15, 2018 -- Three billion miles away on the farthest known major planet in our solar system, an ominous, dark storm – once big enough to stretch across the Atlantic Ocean from Boston to Portugal – is shrinking out of existence as seen in pictures of Neptune taken by NASA’s Hubble Space Telescope.

Immense dark storms on Neptune were first discovered in the late 1980s by NASA’s Voyager 2 spacecraft. Since then, only Hubble has had the sharpness in blue light to track these elusive features that have played a game of peek-a-boo over the years. Hubble found two dark storms that appeared in the mid-1990s and then vanished. This latest storm was first seen in 2015, but is now shrinking.
Like Jupiter’s Great Red Spot (GRS), the storm swirls in an anti-cyclonic direction and is dredging up material from deep inside the ice giant planet’s atmosphere. The elusive feature gives astronomers a unique opportunity to study Neptune’s deep winds, which can’t be directly measured.

The dark spot material may be hydrogen sulfide, with the pungent smell of rotten eggs. Joshua Tollefson from the University of California at Berkeley explained, “The particles themselves are still highly reflective; they are just slightly darker than the particles in the surrounding atmosphere.”

Unlike Jupiter’s GRS, which has been visible for at least 200 years, Neptune’s dark vortices only last a few years. This is the first one that actually has been photographed as it is dying.
"We have no evidence of how these vortices are formed or how fast they rotate,” said Agustín Sánchez-Lavega from the University of the Basque Country in Spain. “It is most likely that they arise from an instability in the sheared eastward and westward winds.”

The dark vortex is behaving differently from what planet-watchers predicted. “It looks like we’re capturing the demise of this dark vortex, and it’s different from what well-known studies led us to expect,” said Michael H. Wong of the University of California at Berkeley, referring to work by Ray LeBeau (now at St. Louis University) and Tim Dowling’s team at the University of Louisville. “Their dynamical simulations said that anticyclones under Neptune’s wind shear would probably drift toward the equator. We thought that once the vortex got too close to the equator, it would break up and perhaps create a spectacular outburst of cloud activity.”
But the dark spot, which was first seen at mid-southern latitudes, has apparently faded away rather than going out with a bang. That may be related to the surprising direction of its measured drift: toward the south pole, instead of northward toward the equator. Unlike Jupiter’s GRS, the Neptune spot is not as tightly constrained by numerous alternating wind jets (seen as bands in Jupiter’s atmosphere). Neptune seems to only have three broad jets: a westward one at the equator, and eastward ones around the north and south poles. The vortex should be free to change traffic lanes and cruise anywhere in between the jets.

“No facilities other than Hubble and Voyager have observed these vortices. For now, only Hubble can provide the data we need to understand how common or rare these fascinating neptunian weather systems may be,” said Wong.
The first images of the dark vortex are from the Outer Planet Atmospheres Legacy (OPAL) program, a long-term Hubble project that annually captures global maps of our solar system’s four outer planets. Only Hubble has the unique capability to probe these worlds in ultraviolet light, which yields important information not available to other present-day telescopes. Additional data, from a Hubble program targeting the dark vortex, are from an international team including Wong, Tollefson, Sánchez-Lavega, Andrew Hsu, Imke de Pater, Amy Simon, Ricardo Hueso, Lawrence Sromovsky, Patrick Fry, Statia Luszcz-Cook, Heidi Hammel, Marc Delcroix, Katherine de Kleer, Glenn Orton, and Christoph Baranec.

Wong’s paper appears online in the Astronomical Journal on Feb. 15, 2018.
          Link with text as above and images of Neptune and its storms: https://www.nasa.gov/feature/goddard/2018/hubble-sees-neptunes-mysterious-shrinking-storm

Friday, February 16, 2018

Photons that Stick Together

Physicists Create New Form of Light
Newly observed optical state could enable quantum computing with photons.
By Jennifer Chu | MIT News Office

February 15, 2018 -- Try a quick experiment: Take two flashlights into a dark room and shine them so that their light beams cross. Notice anything peculiar? The rather anticlimactic answer is, probably not. That’s because the individual photons that make up light do not interact. Instead, they simply pass each other by, like indifferent spirits in the night.

But what if light particles could be made to interact, attracting and repelling each other like atoms in ordinary matter? One tantalizing, albeit sci-fi possibility: light sabers — beams of light that can pull and push on each other, making for dazzling, epic confrontations. Or, in a more likely scenario, two beams of light could meet and merge into one single, luminous stream.

It may seem like such optical behavior would require bending the rules of physics, but in fact, scientists at MIT, Harvard University, and elsewhere have now demonstrated that photons can indeed be made to interact — an accomplishment that could open a path toward using photons in quantum computing, if not in light sabers.

In a paper published today in the journal Science, the team, led by Vladan Vuletic, the Lester Wolfe Professor of Physics at MIT, and Professor Mikhail Lukin from Harvard University, reports that it has observed groups of three photons interacting and, in effect, sticking together to form a completely new kind of photonic matter.

In controlled experiments, the researchers found that when they shone a very weak laser beam through a dense cloud of ultracold rubidium atoms, rather than exiting the cloud as single, randomly spaced photons, the photons bound together in pairs or triplets, suggesting some kind of interaction — in this case, attraction — taking place among them.

While photons normally have no mass and travel at 300,000 kilometers per second (the speed of light), the researchers found that the bound photons actually acquired a fraction of an electron’s mass. These newly weighed-down light particles were also relatively sluggish, traveling about 100,000 times slower than normal noninteracting photons.

Vuletic says the results demonstrate that photons can indeed attract, or entangle each other. If they can be made to interact in other ways, photons may be harnessed to perform extremely fast, incredibly complex quantum computations.

“The interaction of individual photons has been a very long dream for decades,” Vuletic says.

Vuletic’s co-authors include Qi-Yung Liang, Sergio Cantu, and Travis Nicholson from MIT, Lukin and Aditya Venkatramani of Harvard, Michael Gullans and Alexey Gorshkov of the University of Maryland, Jeff Thompson from Princeton University, and Cheng Ching of the University of Chicago.

Biggering and biggering

Vuletic and Lukin lead the MIT-Harvard Center for Ultracold Atoms, and together they have been looking for ways, both theoretical and experimental, to encourage interactions between photons. In 2013, the effort paid off, as the team observed pairs of photons interacting and binding together for the first time, creating an entirely new state of matter.

In their new work, the researchers wondered whether interactions could take place between not only two photons, but more.

“For example, you can combine oxygen molecules to form O2 and O3 (ozone), but not O4, and for some molecules you can’t form even a three-particle molecule,” Vuletic says. “So it was an open question: Can you add more photons to a molecule to make bigger and bigger things?”

To find out, the team used the same experimental approach they used to observe two-photon interactions. The process begins with cooling a cloud of rubidium atoms to ultracold temperatures, just a millionth of a degree above absolute zero. Cooling the atoms slows them to a near standstill. Through this cloud of immobilized atoms, the researchers then shine a very weak laser beam — so weak, in fact, that only a handful of photons travel through the cloud at any one time.

The researchers then measure the photons as they come out the other side of the atom cloud. In the new experiment, they found that the photons streamed out as pairs and triplets, rather than exiting the cloud at random intervals, as single photons having nothing to do with each other.

In addition to tracking the number and rate of photons, the team measured the phase of photons, before and after traveling through the atom cloud. A photon’s phase indicates its frequency of oscillation.

“The phase tells you how strongly they’re interacting, and the larger the phase, the stronger they are bound together,” Venkatramani explains. The team observed that as three-photon particles exited the atom cloud simultaneously, their phase was shifted compared to what it was when the photons didn’t interact at all, and was three times larger than the phase shift of two-photon molecules. “This means these photons are not just each of them independently interacting, but they’re all together interacting strongly.”

Memorable encounters

The researchers then developed a hypothesis to explain what might have caused the photons to interact in the first place. Their model, based on physical principles, puts forth the following scenario: As a single photon moves through the cloud of rubidium atoms, it briefly lands on a nearby atom before skipping to another atom, like a bee flitting between flowers, until it reaches the other end.

If another photon is simultaneously traveling through the cloud, it can also spend some time on a rubidium atom, forming a polariton — a hybrid that is part photon, part atom. Then two polaritons can interact with each other via their atomic component. At the edge of the cloud, the atoms remain where they are, while the photons exit, still bound together. The researchers found that this same phenomenon can occur with three photons, forming an even stronger bond than the interactions between two photons.

“What was interesting was that these triplets formed at all,” Vuletic says. “It was also not known whether they would be equally, less, or more strongly bound compared with photon pairs.”

The entire interaction within the atom cloud occurs over a millionth of a second. And it is this interaction that triggers photons to remain bound together, even after they’ve left the cloud.

“What’s neat about this is, when photons go through the medium, anything that happens in the medium, they ‘remember’ when they get out,” Cantu says.

This means that photons that have interacted with each other, in this case through an attraction between them, can be thought of as strongly correlated, or entangled — a key property for any quantum computing bit.

“Photons can travel very fast over long distances, and people have been using light to transmit information, such as in optical fibers,” Vuletic says. “If photons can influence one another, then if you can entangle these photons, and we’ve done that, you can use them to distribute quantum information in an interesting and useful way.”

Going forward, the team will look for ways to coerce other interactions such as repulsion, where photons may scatter off each other like billiard balls.

“It’s completely novel in the sense that we don’t even know sometimes qualitatively what to expect,” Vuletic says. “With repulsion of photons, can they be such that they form a regular pattern, like a crystal of light? Or will something else happen? It’s very uncharted territory.”

This research was supported in part by the National Science Foundation.

Thursday, February 15, 2018

Alzheimer's Reversed in Mice

Researchers Successfully Reverse
Alzheimer’s Disease in Mouse Model

Newswise from Rockefeller University Press, February 7, 2018 — A team of researchers from the Cleveland Clinic Lerner Research Institute have found that gradually depleting an enzyme called BACE1 completely reverses the formation of amyloid plaques in the brains of mice with Alzheimer’s disease, thereby improving the animals’ cognitive function. The study, which will be published February 14 in the Journal of Experimental Medicine, raises hopes that drugs targeting this enzyme will be able to successfully treat Alzheimer’s disease in humans.

One of the earliest events in Alzheimer’s disease is an abnormal buildup of beta-amyloid peptide, which can form large, amyloid plaques in the brain and disrupt the function of neuronal synapses. Also known as beta-secretase, BACE1 helps produce beta-amyloid peptide by cleaving amyloid precursor protein (APP). Drugs that inhibit BACE1 are therefore being developed as potential Alzheimer’s disease treatments but, because BACE1 controls many important processes by cleaving proteins other than APP, these drugs could have serious side effects.

Mice completely lacking BACE1 suffer severe neurodevelopmental defects. To investigate whether inhibiting BACE1 in adults might be less harmful, Riqiang Yan and colleagues generated mice that gradually lose this enzyme as they grow older. These mice developed normally and appeared to remain perfectly healthy over time.

The researchers then bred these rodents with mice that start to develop amyloid plaques and Alzheimer’s disease when they are 75 days old. The resulting offspring also formed plaques at this age, even though their BACE1 levels were approximately 50% lower than normal. Remarkably, however, the plaques began to disappear as the mice continued to age and lose BACE1 activity, until, at 10 months old, the mice had no plaques in their brains at all.

“To our knowledge, this is the first observation of such a dramatic reversal of amyloid deposition in any study of Alzheimer’s disease mouse models,” says Yan, who will be moving to become chair of the department of neuroscience at the University of Connecticut this spring.

Decreasing BACE1 activity also resulted in lower beta-amyloid peptide levels and reversed other hallmarks of Alzheimer’s disease, such as the activation of microglial cells and the formation of abnormal neuronal processes.

Loss of BACE1 also improved the learning and memory of mice with Alzheimer’s disease. However, when the researchers made electrophysiological recordings of neurons from these animals, they found that depletion of BACE1 only partially restored synaptic function, suggesting that BACE1 may be required for optimal synaptic activity and cognition.

“Our study provides genetic evidence that preformed amyloid deposition can be completely reversed after sequential and increased deletion of BACE1 in the adult,” says Yan. “Our data show that BACE1 inhibitors have the potential to treat Alzheimer’s disease patients without unwanted toxicity. Future studies should develop strategies to minimize the synaptic impairments arising from significant inhibition of BACE1 to achieve maximal and optimal benefits for Alzheimer’s patients.”

Wednesday, February 14, 2018

RNA That Kills Cancers

Huntington's Disease Provides New Cancer Weapon
Scientists harness a super assassin gene for new cancer treatment
By Marla Paul

February 12, 2018 --CHICAGO -- Patients with Huntington’s disease, a fatal genetic illness that causes the breakdown of nerve cells in the brain, have up to 80 percent less cancer than the general population.

Northwestern Medicine scientists have discovered why Huntington’s is so toxic to cancer cells and harnessed it for a novel approach to treat cancer, a new study reports.

Huntington’s is caused by an over abundance of a certain type of repeating RNA sequences in one gene, huntingtin, present in every cell. The defect that causes the disease also is highly toxic to tumor cells. These repeating sequences — in the form of so-called small interfering RNAs — attack genes in the cell that are critical for survival. Nerve cells in the brain are vulnerable to this form of cell death, however, cancer cells appear to be much more susceptible.

“This molecule is a super assassin against all tumor cells,” said senior author Marcus Peter, the Tom D. Spies Professor of Cancer Metabolism at Northwestern University Feinberg School of Medicine. “We’ve never seen anything this powerful.”

Peter also is leader of the Translational Research in Solid Tumors Program at the Robert H. Lurie Comprehensive Cancer Center of Northwestern University. 

Huntington’s disease deteriorates a person’s physical and mental abilities during their prime working years and has no cure.

The study was published Feb. 12 in the journal EMBO Reports.

To test the super assassin molecule in a treatment situation, Peter collaborated with Dr. Shad Thaxton, associate professor of urology at Feinberg, to deliver the molecule in nanoparticles to mice with human ovarian cancer. The treatment significantly reduced the tumor growth with no toxicity to the mice, Peter said. Importantly, the tumors did not develop resistance to this form of cancer treatment.

Peter and Thaxton are now refining the delivery method to increase its efficacy in reaching the tumor. The other challenge for the scientists is figuring out how to stabilize the nanoparticles, so they can be stored.

First and co-corresponding author Andrea Murmann, research assistant professor in medicine at Feinberg, also used the molecule to treat human and mouse ovarian, breast, prostate, liver, brain, lung, skin and colon cancer cell lines. The molecule killed all cancer cells in both species.

The Huntington’s cancer weapon was discovered by Murmann, who had worked with Peter on earlier research that identified an ancient kill-switch present in all cells that destroys cancer.

“I thought maybe there is a situation where this kill switch is overactive in certain people, and where it could cause loss of tissues,” Murmann said. “These patients would not only have a disease with an RNA component, but they also had to have less cancer.“

She started searching for diseases that have a lower rate of cancer and had a suspected contribution of RNA to disease pathology. Huntington’s was the most prominent.

When she looked at the repeating sequences in huntingtin, the gene that causes the disease, she saw a similar composition to the earlier kill switch Peter had found. Both were rich in the C and G nucleotides (molecules that form the building blocks of DNA and RNA).

“Toxicity goes together with C and G richness,” Murmann said. “Those similarities triggered our curiosity.”

In the case of people who have Huntington’s, the gene huntingtin has too many repeating sequences of the triplet sequence CAG. The longer the repeating sequence, the earlier they will develop the disease.

“We believe a short-term treatment cancer therapy for a few weeks might be possible, where we could treat a patient to kill the cancer cells without causing the neurological issues that Huntington’s patients suffer from,” Peter said. Huntington’s patients have a lifetime exposure to these toxic RNA sequences, but generally don’t develop symptoms of the disease until age 40, he noted.

Every child of a parent with Huntington’s has 50/50 chance of carrying the faulty gene. Today there are approximately 30,000 symptomatic Americans and more than 200,000 at-risk of inheriting the disease.

Tuesday, February 13, 2018

The Fish that Clones Itself

Despite Odds, Fish Species that Bypasses
Sexual Reproduction Is Thriving
Success of asexual reproduction in Amazon molly an evolutionary anomaly
by Jim Dryden, Washington University of St. Louis

February 12, 2018 -- The very rare animals that reproduce asexually — only about one in 1,000 of all living vertebrate species — are thought to be at an evolutionary disadvantage compared with their sexually reproduced counterparts. But that theory doesn’t hold true regarding the Amazon molly, an all-female fish species that has thrived for millennia in the fresh waters along the Mexico-Texas border.

To better understand how this fish’s reproduction deviates from the norm, an international team of scientists has sequenced the first Amazon molly genome and the genomes of the original parental species that created this unique fish. Their findings suggest that the molly’s thriving existence is not totally unexpected since they found the fish has a hardy genetic makeup that is often rare in nature and gives the animals some predicted survival benefits.

“It appears the stars aligned for this species,” said first author Wesley C. Warren, PhD, an assistant director at the McDonnell Genome Institute at Washington University School of Medicine in St. Louis. “The hybridization of two different species’ genomes into one new one would require nearly perfect compatibility between the elements of those parent genomes to bypass the sexual reproduction practiced by most vertebrate species.”

The findings are published Feb. 12 in the journal Nature Ecology & Evolution.

Ever since scientists, in 1932, determined that the Amazon molly was the first known asexual vertebrate, they have wondered how this came to be.

One of the theories that spells out why asexual reproduction should stand in the way of a species’ sustainability is the idea that if no new DNA is introduced during reproduction, then harmful gene mutations can accumulate over successive generations, leading to eventual extinction. Another hypothesis states that because asexual reproduction limits genetic diversity within a species, the animals eventually become unable to adapt to changes in the environment.

“The expectation is that these asexual organisms are at a genetic disadvantage,” said Warren, also an assistant professor of genetics. “In nature, the Amazon molly is doing quite well.”

The researchers found that the Amazon molly resulted from a sexual reproduction event involving two different species of fish, when an Atlantic molly first mated with a Sailfin molly 100,000 to 200,000 years ago. Since then, the resulting Amazon molly has been a hybrid species that remarkably has remained frozen in evolutionary time — yet still continues to thrive.

“That’s about 500,000 generations if you calculate it out to the present day,” said Warren. “The expectation is that many harmful mutations would accumulate in that time, but that’s not what we found.”

The Amazon molly reproduces by “mating” with a male fish of a related species. But the male’s DNA is not incorporated into the offspring. Instead, mating with the male fish triggers the replication of the entire maternal genome. In essence, mollies clone themselves. They don’t lay eggs but instead give birth to large broods of live offspring.

Scientists have long theorized that clones, by failing to purge harmful mutations, should experience decay in the genome and eventual extinction over generations.

“This study caps an intensive, collaborative study, marking the first glimpse of the genomic features of an asexual vertebrate and setting up a platform for future molecular, cellular and developmental work in this interesting species,” said Michael Lynch, PhD, director of the Biodesign Center for Mechanisms of Evolution at Arizona State University.

So although the Amazon molly has thrived for thousands of years, it remains resistant to giving away its genomic secrets — for now.

“It may be that the Amazon molly has the best of both worlds,” said Manfred Schartl, professor and chair of biochemistry at the University of Wurzburg in Wurzburg, Germany. “It seems to have some advantages that we see in species that reproduce sexually and other advantages normally seen in species that produce offspring nonsexually, such as large population sizes”

Whatever the reasons, the researchers said the Amazon molly is an exception to ideas about the evolutionary disadvantages of asexual reproduction.

Monday, February 12, 2018

Desalination for Lithium

New Lithium Collection Method
Could Boost Global Supply

University of Texas, February 9, 2018 -- With continual technological advancements in mobile devices and electric cars, the global demand for lithium has quickly outpaced the rate at which it can be mined or recycled, but a University of Texas at Austin professor and his research team may have a solution.

Benny Freeman, professor in the McKetta Department of Chemical Engineering in the Cockrell School of Engineering, and his colleagues at the Monash University Department of Chemical Engineering and the Commonwealth Scientific and Industrial Research Organisation (CSIRO) in Australia have recently discovered a new, efficient way to extract lithium and other metals and minerals from water. They published their findings in the Feb. 9 issue of Science Advances.

The team’s technique uses a metal-organic-framework membrane that mimics the filtering function, or “ion selectivity,” of biological cell membranes. The membrane process easily and efficiently separates metal ions, opening the door to revolutionary technologies in the water and mining industries and potential economic growth opportunities in Texas.

The Barnett and Eagle Ford shale formations in Texas contain high amounts lithium, and the produced wastewater generated by hydraulic fracturing in those areas has high concentrations of lithium. Instead of discarding the produced water, the team’s membrane filter could extract the resulting lithium and put it to use in other industries.

“Produced water from shale gas fields in Texas is rich in lithium. Advanced separation materials concepts such as ours could potentially turn this waste stream into a resource recovery opportunity,” Freeman said.

Each well in the Barnett and Eagle Ford can generate up to 300,000 gallons of produced water per week. Using their new process, Freeman and his team conservatively estimate that from just one week’s worth of produced water, enough lithium can be recovered to power 200 electric cars or 1.6 million smartphones.

In addition, the team’s process could help with water desalination. Unlike the existing reverse-osmosis membranes responsible for more than half of the world’s current water desalination capacity, the new membrane process dehydrates ions as they pass through the membrane channels and removes only select ions, rather than indiscriminately removing all ions. The result is a process that costs less and consumes less energy than conventional methods.

The team’s material operates on principles inspired by highly effective biological cell membranes, whose mechanism of operation was discovered by Roderick MacKinnon and Peter Agre and was the subject of the 2003 Nobel Prize in chemistry.

“The prospect of using metal-organic frameworks for sustainable water filtration is incredibly exciting from a public-good perspective, while delivering a better way of extracting lithium ions to meet global demand could create new industries,” said Anita Hill, CSIRO’s chief scientist.

Funding for this research was provided by the Australian Research Council, the Australian-American Fulbright Commission, the Commonwealth Scientific and Industrial Research Organization and the National Computational Infrastructure in Australia.

Sunday, February 11, 2018

Trillion Dollar U.S. Coin

The trillion dollar coin is a concept that emerged during the United States debt-ceiling crisis in 2011, as a proposed way to bypass any necessity for the United States Congress to raise the country's borrowing limit, through the minting of very high-value platinum coins. The concept gained more mainstream attention by late 2012 during the debates over the United States fiscal cliff negotiations and renewed debt-ceiling discussions. After reaching the headlines during the week of January 7, 2013, use of the trillion dollar coin concept was ultimately rejected by the Federal Reserve and the Treasury. Five days later, Senate Minority Whip John Cornyn announced that Senate Republicans would end their threat to block an increase in the debt ceiling.

The concept of striking a trillion dollar coin that would generate one trillion dollars in seigniorage, which would be off-budget, or numismatic profit, which would be on-budget, and be transferred to the Treasury, is based on the authority granted by Section 31 U.S.C. § 5112 of the United States Code for the Treasury Department to "mint and issue platinum bullion coins" in any denominations the Secretary of the Treasury may choose. Thus, if the Treasury were to mint one trillion dollar coins, it could deposit such coins at the Federal Reserve's Treasury account instead of issuing new debt.

31 U.S.C. 5112(k) as originally enacted by Public Law 104-208 in 1996:

The Secretary may mint and issue bullion and proof platinum coins in accordance with such specifications, designs, varieties, quantities, denominations, and inscriptions as the Secretary, in the Secretary's discretion, may prescribe from time to time.

In 2000, the word "bullion" was replaced with "platinum bullion coins".

Platinum bullion coins can, by this statute, be minted in any denomination, whereas coins in any other specified metal are restricted to amounts of $50, $25, $10, $5 and $1. This is the origin of the concept of minting a very high denomination coin, since the platinum clause provides the only loophole.

Philip N. Diehl, former director of the United States Mint and with Republican Congressman Michael Castle co-author of the platinum coin law, has said the procedure would be permitted by the statute. However, Castle says he never intended such a use. The platinum coinage provision was eventually passed by a Republican Congress over the objections of a Democratic Treasury in 1996.

Laurence Tribe, a constitutional law professor at Harvard Law School, said the legal basis of the trillion dollar coin is sound and that the coin could not be challenged in court as no one would have standing to do so. Professor Jonathan H. Adler of the Case Western Reserve University School of Law has said that he believes the legality of the trillion dollar coin to be dubious.

Analysis and Reaction

Some commentators have argued that although the concept may be strictly legal, it would weaken the checks and balances system of U.S. government even if the spending that the minting of the coin would allow has already been authorized by Congress. Journalist Megan McArdle wrote that "minting a $1 trillion coin neatly end-runs GOP obstructionists, but only by proving that the president himself has little respect for the institutional restraints on his office." Another journalist, Felix Salmon, wrote that the concept "would effectively mark the demise of the three-branch system of government, by allowing the executive branch to simply steamroller the rights and privileges of the legislative branch". Salmon went on to explain that he does not agree with what Congressional Republicans are doing, but they have a right to do that, and the president should not use the trillion dollar coin option to circumvent them. In Salmon's words, "Yes, the legislature is behaving like a bunch of utter morons if they think that driving the US government into default is a good idea. But it's their right to behave like a bunch of utter morons."

On the other hand, many economists and business analysts endorsed the coin as a way to counter threats by congressional Republicans to force the country into default by refusing to raise the debt limit. Paul Krugman said "So minting the coin would be undignified, but so what? At the same time, it would be economically harmless — and would both avoid catastrophic economic developments and help head off government by blackmail." He also declared the trillion dollar coin debate to be "the most important fiscal policy debate of our lifetimes".

Michael Steel, spokesperson of House Speaker John Boehner, dismissed the concept by comparing it to a Simpsons episode called "The Trouble with Trillions", which aired 13 years before the United States debt-ceiling crisis, in which Homer Simpson is on a mission in search of a missing trillion dollar bill.

On January 7, 2013, Republican congressman Greg Walden announced he would introduce a bill to close the platinum coin loophole. Rep. Walden said that the intention is to "take the proposal off the table". The bill is opposed by New York representative Jerry Nadler, who says that the idea remains a valid option.

On January 12, 2013, the Treasury and Federal Reserve announced they would not mint a platinum coin, and five days later, Senate Minority Whip John Cornyn (R-Texas) announced that Senate Republicans would end their threat to block an increase in the debt ceiling.

                               https://en.wikipedia.org/wiki/Trillion_dollar_coin

See also:  https://en.wikipedia.org/wiki/National_debt_of_the_United_States