Wednesday, October 18, 2017

Locking Up HIV RNA

New Research Opens the Door
to ‘Functional Cure’ for HIV

JUPITER, FL – October 17, 2017 – In findings that open the door to a completely different approach to curing HIV infections, scientists from the Florida campus of The Scripps Research Institute (TSRI) have for the first time shown that a novel compound effectively suppresses production of the virus in chronically infected cells, and prevents viral rebound, even when those infected cells are subjected to vigorous stimulation.

The study, led by TSRI Associate Professor Susana Valente, was published online Oct. 17 before print in the journal Cell Reports.

“No other anti-retroviral used in the clinic today is able to completely suppress viral production in infected cells in vivo,” Valente said. “When combining this drug with the standard cocktail of anti-retrovirals used to suppress infection in humanized mouse models of HIV-1 infection, our study found a drastic reduction in virus RNA present—it is really the proof-of-concept for a ‘functional cure.’”

Valente, a pioneer in this new approach, calls it “Block-and-Lock”—the approach blocks reactivation of the virus in cells, even during treatment interruptions, and locks HIV into a durable state of latency.

Valente and her colleagues use a derivative of a natural compound called didehydro-Cortistatin A (dCA), which blocks replication in HIV-infected cells by inhibiting the viral transcriptional activator, called Tat, halting viral production, reactivation and replenishment of the latent viral reservoir.

“Combining dCA with anti-retroviral therapy accelerates HIV-1 suppression and prevents viral rebound after treatment interruption, even during strong cellular activation,” Valente said. “It’s important to note that our study uses the maximum tolerable dose of the drug—with virtually no side effects.”

The scientists studied the combination therapy in a mouse model of HIV latency and persistence. Once the combined treatment regimen was halted, viral rebound was delayed up to 19 days, compared with just seven days in mouse models receiving only anti-retroviral treatment.

“This demonstrates the potential of ‘block-and-lock’ strategies,” said TSRI Research Associate Cari F. Kessing, co-first author of the study. “This study shows that a ‘functional cure’ approach can succeed in reducing residual virus in the blood during anti-retroviral treatment and limiting viral rebound during treatment interruption.”

“In half of the dCA treated mice, the virus was undetectable for 16 days after all treatment was halted,” said the University of North Carolina’s Christopher Nixon, another first author.

“We blocked Tat, and the cell’s machinery did the rest,” said TSRI Research Associate Chuan Li, a coauthor of the study. “The result was that the HIV promoter becomes repressed.”

Valente pointed out that the animal models were exposed to just a single month of treatment. “That’s a relatively short period of time,” she said. “We think longer treatments will result in longer, or even permanent, rebound delays. The question is how long? We’re studying that now.”

Because any viral rebound of HIV comes with a host of adverse effects, Valente noted, blocking that rebound would automatically reduce those effects.

“This is the only class of drugs that stops infected cells from making viruses outright,” said Valente. “All current antivirals work later in the viral lifecycle, so only a HIV transcriptional inhibitor like dCA can stop the side effects of low-level virus production.”

In addition to Valente, Kessing, Li and Nixon, other authors of the study, “ In Vivo Suppression Of HIV Rebound By Didehydro-1 Cortistatin A, A ‘Block-And-Lock’  Strategy For HIV-1 Treatment,” are Guillaume Mousseau and Mohammad Fallahi of TSRI; Perry M. Tsai, Phong T. Ho, Jenna B. Honeycutt and J. Victor Garcia of the University of North Carolina; and Hiroshi Takata and Lydie Trautmann of Walter Reed Army Institute of Research and the Henry M. Jackson Foundation for the Advancement of Military Medicine.

Tuesday, October 17, 2017

Whale and Dolphin Societies

Whales and Dolphins Have Rich
‘human-like’ Cultures and Societies

University of Manchester – October 16, 2017 -- Whales and dolphins (Cetaceans) live in tightly-knit social groups, have complex relationships, talk to each other and even have regional dialects – much like human societies.

A major new study, published today in Nature Ecology & Evolution (Monday 16th October), has linked the complexity of Cetacean culture and behaviour to the size of their brains.

The research was a collaboration between scientists at The University of Manchester, The University of British Columbia, Canada, The London School of Economics and Political Science (LSE) and Stanford University, United States.

The study is first of its kind to create a large dataset of cetacean brain size and social behaviours. The team compiled information on 90 different species of dolphins, whales, and porpoises. It found overwhelming evidence that Cetaceans have sophisticated social and cooperative behaviour traits, similar to many found in human culture. The study demonstrates that these societal and cultural characteristics are linked with brain size and brain expansion – also known as encephalisation.

The long list of behavioural similarities includes many traits shared with humans and other primates such as:

·         complex alliance relationships – working together for mutual benefit

·         social transfer of hunting techniques – teaching how to hunt and using tools

·         cooperative hunting

·         complex vocalizations, including regional group dialects – ‘talking’ to each other

·         vocal mimicry and ‘signature whistles’ unique to individuals – using ‘name’ recognition

·         interspecific cooperation with humans and other species – working with different species

·         alloparenting – looking after youngsters that aren’t their own

·         social play 

Dr Susanne Shultz, an evolutionary biologist in Manchester’s School of Earth and Environmental Sciences, said: “As humans, our ability to socially interact and cultivate relationships has allowed us to colonise almost every ecosystem and environment on the planet. We know whales and dolphins also have exceptionally large and anatomically sophisticated brains and, therefore, have created a similar marine based culture.
“That means the apparent co-evolution of brains, social structure, and behavioural richness of marine mammals provides a unique and striking parallel to the large brains and hyper-sociality of humans and other primates on land. Unfortunately, they won’t ever mimic our great metropolises and technologies because they didn’t evolve opposable thumbs.”
The team used the dataset to test the social brain hypothesis (SBH) and cultural brain hypothesis (CBH). The SBH and CBH are evolutionary theories originally developed to explain large brains in primates and land mammals.
They argue that large brains are an evolutionary response to complex and information-rich social environments. However, this is the first time these hypotheses have been applied to ‘intelligent’ marine mammals on such a large scale.
Dr Michael Muthukrishna, Assistant Professor of Economic Psychology at LSE, added: “This research isn’t just about looking at the intelligence of whales and dolphins, it also has important anthropological ramifications as well. In order to move toward a more general theory of human behaviour, we need to understand what makes humans so different from other animals. And to do this, we need a control group. Compared to primates, cetaceans are a more “alien” control group.”
Dr Kieran Fox, a neuroscientist at Stanford University, added: “Cetaceans have many complex social behaviours that are similar to humans and other primates. They, however, have different brain structures from us, leading some researchers to argue that whales and dolphins could not achieve higher cognitive and social skills. I think our research shows that this is clearly not the case. Instead, a new question emerges: How can very diverse patterns of brain structure in very different species nonetheless give rise to highly similar cognitive and social behaviours?”
Reference: 'The social and cultural roots of whale and dolphin brains, Nature Ecology & Evolution (2017). DOI: 10.1038/s41559-017-0336-y'

Monday, October 16, 2017

Neutron Stars Observed Colliding

GW170817 was a gravitational wave signal observed by the LIGO/Virgo collaboration on 17 August 2017, and was the first gravitational wave event that was observed to have a simultaneous electromagnetic signal. The gravitational wave signal, which had a duration of about 100 seconds, is the first gravitational wave detection of the merger of two neutron stars, and was associated with a soft short gamma-ray burst GRB 170817A, and an optical transient that was found in the galaxy NGC 4993. No neutrino candidates consistent with the source were found in follow-up searches.

Announcement of the Event

The event was officially announced on 16 October 2017 at press conferences at the National Press Club in Washington, D.C. and at ESO's headquarter in Garching, Germany.

The first public information about the event was tweeted by astronomer J. Craig Wheeler of the University of Texas at Austin on 18 August 2017. He later deleted the tweet and apologized for scooping the official announcement protocol. Other people followed up on the rumour, and reported that the public logs of several major telescopes listed priority interrupts in order to observe NGC 4993, a galaxy 40 Mpc (130 Mly) away in the Hydra constellation. The collaboration had earlier declined to comment on the rumors, not adding to a previous announcement that there were several triggers under analysis.

Gravitational Wave Detection

The gravitational wave signal lasted for about 100 seconds and covered about 3000 cycles, with the gravitational wave frequency increasing to a few hundred hertz (cycles per second). It arrived first at the Virgo detector in Italy, then 22 milliseconds later at the LIGO-Livingston detector in Louisiana, U.S., and another 3 milliseconds later at the LIGO-Hanford detector in Washington State, U.S. The three detections localized the source to an area of 28 degrees squared in the Southern sky with a 90% probability.

Scientific Impact

This event is the strongest evidence to confirm the hypothesis that mergers of binary stars are linked to short gamma-ray bursts. The event also provides a limit on the difference between the speed of light and that of gravity. Assuming the first photons were emitted between 0 and 10 seconds after peak gravitational wave emission constrains the difference between the speeds of gravitational and electromagnetic waves, vGW - vEM, to between -3×10−15 and +7×10−16 times the speed of light. In addition, it allows investigation of Lorentz invariance. The limits of possible violations of Lorentz invariance (values of 'gravity sector coefficients') are reduced by the new observations, in some cases by ten orders of magnitude.

Gravitational wave signals such as GW170817 can be used as a standard siren to provide an independent measurement of the Hubble constant.

Electromagnetic observations helped to support the theory that the mergers of neutron stars contribute to r-process nucleosynthesis.

Sunday, October 15, 2017

Secret Societies Still Exist

A secret society is a club or an organization whose activities, events, and inner functioning are concealed from non-members. The society may or may not attempt to conceal its existence. The term usually excludes covert groups, such as intelligence agencies or guerrilla insurgencies, that hide their activities and memberships but maintain a public presence. The exact qualifications for labeling a group a secret society are disputed, but definitions generally rely on the degree to which the organization insists on secrecy, and might involve the retention and transmission of secret knowledge, the denial of membership or knowledge of the group, the creation of personal bonds between members of the organization, and the use of secret rites or rituals which solidify members of the group.  For example, the Thuggee were a secret cult of assassins who worshipped the Hindu goddess Kali.

Characteristics of Secret Societies

Anthropologically and historically, secret societies are deeply interlinked with the concept of the Männerbund, the all-male "warrior-band" or "warrior-society" of pre-modern cultures (see H. Schurtz, Alterklassen und Männerbünde, Berlin, 1902; A. Van Gennep, The Rites of Passage, Chicago, 1960).

A purported "family tree of secret societies" has been proposed, although it may not be comprehensive

Alan Axelrod, author of the International Encyclopedia of Secret Societies and Fraternal Orders, defines a secret society as an organization that:

  • Is exclusive.
  • Claims to own special secrets.
  • Shows a strong inclination to favor its own.

David V. Barrett, author of Secret Societies: From the Ancient and Arcane to the Modern and Clandestine, uses slightly different terms to define what qualifies a secret society. He defines it as any group that possesses the following characteristics:

  • It has "carefully graded and progressed teachings"
  • Teachings are "available only to selected individuals"
  • Teachings lead to "hidden (and 'unique') truths"
  • Truths bring "personal benefits beyond the reach and even the understanding of the uninitiated."

Barrett goes on to say that "a further characteristic common to most of them is the practice of rituals which non-members are not permitted to observe, or even to know the existence of." Barrett's definition would rule out many organizations called secret societies; graded teaching is usually not part of the American college fraternities, the Carbonari, or the 19th century Know Nothings.

Political Secret Societies

Because some secret societies have political aims, they are illegal in several countries. Italy (Constitution of Italy, Section 2, Articles 13-28) and Poland, for example, ban secret political parties and political organizations in their constitutions.

Secret Societies at Colleges and Universities

Many student societies established on university campuses in the United States have been considered secret societies. Perhaps one of the most famous secret collegiate societies is Skull and Bones at Yale University. The influence of undergraduate secret societies at colleges such as Harvard College, Dartmouth College, the University of Chicago, the University of Virginia, Georgetown University, New York University, and Wellesley College has been publicly acknowledged, if anonymously and circumspectly, since the 19th century.

British Universities, too, have a long history of secret societies or quasi-secret societies, such as The Pitt Club at Cambridge University, Bullingdon Club at Oxford University, and the 16' Club at St David's College. One of the best known British secret societies is the Cambridge Apostles, founded as an essay and debating society in 1820.

In France, Vandermonde is the secret society of the Conservatoire National des Arts et Métiers.

Notable examples in Canada include Episkopon at the University of Toronto's Trinity College, and the Society of Thoth at the University of British Columbia.

Secret societies are disallowed in a few colleges. The Virginia Military Institute has rules that no cadet may join a secret society, and secret societies have been banned at Oberlin College from 1847 to the present, and at Princeton University since the beginning of the 20th century.

Internet Secret Societies

While their existence had been speculated for years, internet-based secret societies first became known to the public in 2012 when the secret society known as Cicada 3301 began recruiting from the public via internet-based puzzles. The goals of the society remain unknown, but it is believed that they are involved in cryptography and cryptocurrency.

The only secret society abolished and then legalized is that of the philomaths; it is now a legitimate academic association founded on a strict selection of its members.

Saturday, October 14, 2017

Research on Blood Substitutes

A blood substitute (also called artificial blood or blood surrogate) is a substance used to mimic and fulfill some functions of biological blood. It aims to provide an alternative to blood transfusion, which is transferring blood or blood-based products from one person into another. Thus far, there are no well-accepted oxygen-carrying blood substitutes, which is the typical objective of a red blood cell transfusion; however, there are widely available non-blood volume expanders for cases where only volume restoration is required. These are helping doctors and surgeons avoid the risks of disease transmission and immune suppression, address the chronic blood donor shortage, and address the concerns of Jehovah's Witnesses and others who have religious objections to receiving transfused blood.

The main categories of 'oxygen-carrying' blood substitutes being pursued are hemoglobin-based oxygen carriers (HBOC) and perfluorocarbon-based oxygen carriers (PFBOC). Oxygen therapeutics are in clinical trials in the U.S. and Europe, and Hemopure is available in South Africa.

Oxygen Carrying Substitutes

An oxygen-carrying blood substitute, sometimes called artificial haemoglobin, is an artificially made red blood cell substitute whose main function is to carry oxygen, as does natural hemoglobin. The use of oxygen-carrying blood substitutes is often called oxygen therapeutics to differentiate from true blood substitutes. The initial goal of oxygen carrying blood substitutes is merely to mimic blood's oxygen transport capacity. There is additional longer range research on true artificial red and white blood cells which could theoretically compose a blood substitute with higher fidelity to human blood. Unfortunately, oxygen transport, one function that distinguishes real blood from other volume expanders, has been very difficult to reproduce.

There are two basic approaches to constructing an oxygen therapeutic. The first is perfluorocarbons (PFC), chemical compounds which can carry and release oxygen. The specific PFC usually used is either perfluorodecalin or dodecafluoropentane emulsion (DDFPe). The second approach is haemoglobin derived from humans, animals, or artificially via recombinant technology, or via stem cell production of red blood cells in vitro.

Motivation for Research on Substitutes for Blood

Oxygen therapeutics, even if widely available, would not eliminate the use of human blood, which performs various functions besides oxygen transport. However oxygen therapeutics have major advantages over human blood in various situations, especially trauma.

Blood substitutes are useful for the following reasons. Although the blood supply in many countries is very safe, this is not the case for all regions of the world. Blood transfusion is the second largest source of new HIV infections in Nigeria. In certain regions of southern Africa, it is believed that as much as 40% of the population has HIV/AIDS, although testing is not financially feasible. A disease-free source of blood substitutes would be incredibly beneficial in these regions.

In battlefield scenarios, it is often impossible to administer rapid blood transfusions. Medical care in the armed services would benefit from a safe, easy way to manage blood supply.

Great benefit could be derived from the rapid treatment of patients in trauma situations. Because these blood substitutes do not contain any of the antigens that determine blood type, they can be used across all types without immunologic reactions.

While it is true that receiving a unit of transfused blood in the US does not carry many risks, with only 10 to 20 deaths per million units, blood substitutes could eventually improve on this. There is no practical way to test for prion-transmitted diseases in donated blood, such as mad cow and Creutzfeldt–Jakob disease, and other disease could emerge as problems for the blood supply, including smallpox and SARS.

Transfused blood is currently more cost effective, but there are reasons to believe this may change. For example, the cost of blood substitutes may fall as manufacturing becomes refined.

Blood substitutes can be stored for much longer than transfusable blood, and can be kept at room temperature. Most haemoglobin-based oxygen carriers in trials today carry a shelf life of between 1 and 3 years, compared to 42 days for donated blood, which needs to be kept refrigerated.

Blood substitutes allow for immediate full capacity oxygen transport, as opposed to transfused blood which can require about 24 hours to reach full oxygen transport capacity due to 2,3‑diphosphoglycerate depletion. Also, in comparison, natural replenishment of lost red blood cells usually takes months, so an oxygen-carrying blood substitute can perform this function until blood is naturally replenished.

Oxygen-carrying blood substitutes also would become an alternative for those patients that refuse blood transfusions for religious or cultural reasons, such as Jehovah's Witnesses.

Synthetic oxygen carriers may also show potential for cancer treatment, as their reduced size allows them to diffuse more effectively through poorly vasculated tumour tissue, increasing the effectiveness of treatments like photodynamic therapy and chemotherapy.

The U.S. military is one of the greatest proponents of oxygen therapeutics, mainly because of the vital need and benefits in a combat scenario. Since oxygen therapeutics are not yet widely available, the United States Army is experimenting with varieties of dried blood, which take up less room, weigh less and can be used much longer than blood plasma. Saline has to be added prior to use. These properties make it better for first aid during combat than whole blood or packed red cells.


Haemoglobin-based blood substitutes may increase the odds of deaths and heart attacks.

According to studies of outcomes of transfusions given to trauma patients in 2008, blood substitutes yielded a 30% increase in the risk of death and about a threefold increase in the chance of having a heart attack for the recipients. More than 3,711 patients were tested in sixteen studies using five types of artificial blood. Public Citizen sued the U.S. Food and Drug Administration (FDA) to obtain information on the duration of these studies which were found to have been conducted from 1998 until 2007. The FDA permits artificial blood transfusions in the US without informed consent under a special exemption from requirements of informed consent during traumatic care.

Other Functions than Carrying Oxygen

The functions of blood are many. Normally, for example, white blood cells defend against disease, platelets allow clotting, and blood proteins perform various functions. In addition, the blood composition includes additional molecules and electrolytes to function properly. Some of these components are substitutable with modern technology, and may, at least, be added to an oxygen-carrying blood substitute to create a more complete blood substitute.

Volume expanders could conceptually be called blood substitutes as well, but they are usually not within the scope of blood substitutes. Still, they are sometimes called "plasma substitutes".



Friday, October 13, 2017

Was "Missing Link" a Midget?

New Study Suggests that Last Common Ancestor of Humans and Apes Was Smaller than Thought
Researchers propose that ape ancestor was about the size of a gibbon

American Museum of Natural History – October 11, 2017 -- New research suggests that the last common ancestor of apes--including great apes and humans--was much smaller than previously thought, about the size of a gibbon. The findings, published today in the journal Nature Communications, are fundamental to understanding the evolution of the human family tree.

"Body size directly affects how an animal relates to its environment, and no trait has a wider range of biological implications," said lead author Mark Grabowski, a visiting assistant professor at the Eberhard Karls University of Tübingen in Germany who conducted the work while he was a postdoctoral fellow in the American Museum of Natural History's Division of Anthropology. "However, little is known about the size of the last common ancestor of humans and all living apes. This omission is startling because numerous paleobiological hypotheses depend on body size estimates at and prior to the root of our lineage."

Among living primates, humans are most closely related to apes, which include the lesser apes (gibbons) and the great apes (chimpanzees, gorillas, and orangutans). These "hominoids" emerged and diversified during the Miocene, between about 23 million to 5 million years ago. Because fossils are so scarce, researchers do not know what the last common ancestors of living apes and humans looked like or where they originated.

To get a better idea of body mass evolution within this part of the primate family tree, Grabowski and coauthor William Jungers from Stony Brook University compared body size data from modern primates, including humans, to recently published estimates for fossil hominins and a wide sample of fossil primates including Miocene apes from Africa, Europe, and Asia. They found that the common ancestor of apes was likely small, probably weighing about 12 pounds, which goes against previous suggestions of a chimpanzee-sized, chimpanzee-like ancestor.

Among other things, the finding has implications for a behavior that's essential for large, tree-dwelling primates: it implies that "suspensory locomotion," overhand hanging and swinging, arose for other reasons than the animal simply getting too big to walk on top of branches. The researchers suggest that the ancestor was already somewhat suspensory, and larger body size evolved later, with both adaptations occurring at separate points. The development of suspensory locomotion could have been part of an "arms race" with a growing number of monkey species, the researchers said. Branch swinging allows an animal to get to a prized and otherwise inaccessible food--fruit on the edges of foliage--and larger body would let them engage in direct confrontation with monkeys when required.

The new research also reveals that australopiths, a group of early human relatives, were actually on average smaller than their ancestors, and that this smaller size continued until the arrival of Homo erectus.

"There appears to be a decrease in overall body size within our lineage, rather than size simply staying the same or getting bigger with time, which goes against how we generally think about evolution," Grabowski said.

Thursday, October 12, 2017

"Air-breathing" Battery Much Greener

Making Renewable Power
More Viable for the Grid
“Air-breathing” battery can store electricity for months, for about a fifth the cost of current technologies.
Rob Matheson | MIT News Office

October 11, 2017 -- Wind and solar power are increasingly popular sources for renewable energy. But intermittency issues keep them from connecting widely to the U.S. grid: They require energy-storage systems that, at the cheapest, run about $100 per kilowatt hour and function only in certain locations.

Now MIT researchers have developed an “air-breathing” battery that could store electricity for very long durations for about one-fifth the cost of current technologies, with minimal location restraints and zero emissions. The battery could be used to make sporadic renewable power a more reliable source of electricity for the grid.

For its anode, the rechargeable flow battery uses cheap, abundant sulfur dissolved in water. An aerated liquid salt solution in the cathode continuously takes in and releases oxygen that balances charge as ions shuttle between the electrodes. Oxygen flowing into the cathode causes the anode to discharge electrons to an external circuit. Oxygen flowing out sends electrons back to the anode, recharging the battery.

“This battery literally inhales and exhales air, but it doesn’t exhale carbon dioxide, like humans — it exhales oxygen,” says Yet-Ming Chiang, the Kyocera Professor of Materials Science and Engineering at MIT and co-author of a paper describing the battery. The research appears today in the journal Joule.

The battery’s total chemical cost — the combined price of the cathode, anode, and electrolyte materials — is about 1/30th the cost of competing batteries, such as lithium-ion batteries. Scaled-up systems could be used to store electricity from wind or solar power, for multiple days to entire seasons, for about $20 to $30 per kilowatt hour.

Co-authors with Chiang on the paper are: first author Zheng Li, who was a postdoc at MIT during the research and is now a professor at Virginia Tech; Fikile R. Brushett, the Raymond A. and Helen E. St. Laurent Career Development Professor of Chemical Engineering; research scientist Liang Su; graduate students Menghsuan Pan and Kai Xiang; and undergraduate students Andres Badel, Joseph M. Valle, and Stephanie L. Eiler.

Finding the right balance

Development of the battery began in 2012, when Chiang joined the Department of Energy’s Joint Center for Energy Storage Research, a five-year project that brought together about 180 researchers to collaborate on energy-saving technologies. Chiang, for his part, focused on developing an efficient battery that could reduce the cost of grid-scale energy storage.

A major issue with batteries over the past several decades, Chiang says, has been a focus on synthesizing materials that offer greater energy density but are very expensive. The most widely used materials in lithium-ion batteries for cellphones, for instance, have a cost of about $100 for each kilowatt hour of energy stored.

“This meant maybe we weren’t focusing on the right thing, with an ever-increasing chemical cost in pursuit of high energy-density,” Chiang says. He brought the issue to other MIT researchers. “We said, ‘If we want energy storage at the terawatt scale, we have to use truly abundant materials.’”

The researchers first decided the anode needed to be sulfur, a widely available byproduct of natural gas and petroleum refining that’s very energy dense, having the lowest cost per stored charge next to water and air. The challenge then was finding an inexpensive liquid cathode material that remained stable while producing a meaningful charge. That seemed improbable — until a serendipitous discovery in the lab.

On a short list of candidates was a compound called potassium permanganate. If used as a cathode material, that compound is “reduced” — a reaction that draws ions from the anode to the cathode, discharging electricity. However, the reduction of the permanganate is normally impossible to reverse, meaning the battery wouldn’t be rechargeable.

Still, Li tried. As expected, the reversal failed. However, the battery was, in fact, recharging, due to an unexpected oxygen reaction in the cathode, which was running entirely on air. “I said, ‘Wait, you figured out a rechargeable chemistry using sulfur that does not require a cathode compound?’ That was the ah-ha moment,” Chiang says.

Using that concept, the team of researchers created a type of flow battery, where electrolytes are continuously pumped through electrodes and travel through a reaction cell to create charge or discharge. The battery consists of a liquid anode (anolyte) of polysulfide that contains lithium or sodium ions, and a liquid cathode (catholyte) that consists of an oxygenated dissolved salt, separated by a membrane.

Upon discharging, the anolyte releases electrons into an external circuit and the lithium or sodium ions travel to the cathode. At the same time, to maintain electroneutrality, the catholyte draws in oxygen, creating negatively charged hydroxide ions. When charging, the process is simply reversed. Oxygen is expelled from the catholyte, increasing hydrogen ions, which donate electrons back to the anolyte through the external circuit.

“What this does is create a charge balance by taking oxygen in and out of the system,” Chiang says.

Because the battery uses ultra-low-cost materials, its chemical cost is one of the lowest — if not the lowest — of any rechargeable battery to enable cost-effective long-duration discharge. Its energy density is slightly lower than today’s lithium-ion batteries.

“It’s a creative and interesting new concept that could potentially be an ultra-low-cost solution for grid storage,” says Venkat Viswanathan, an assistant professor of mechanical engineering at Carnegie Mellon University who studies energy-storage systems.

Lithium-sulfur and lithium-air batteries — where sulfur or oxygen are used in the cathode — exist today. But the key innovation of the MIT research, Viswanathan says, is combining the two concepts to create a lower-cost battery with comparable efficiency and energy density. The design could inspire new work in the field, he adds: “It’s something that immediately captures your imagination.”

Making renewables more reliable

The prototype is currently about the size of a coffee cup. But flow batteries are highly scalable, Chiang says, and cells can be combined into larger systems.

As the battery can discharge over months, the best use may be for storing electricity from notoriously unpredictable wind and solar power sources. “The intermittency for solar is daily, but for wind it’s longer-scale intermittency and not so predictable. When it’s not so predictable you need more reserve — the capability to discharge a battery over a longer period of time — because you don’t know when the wind is going to come back next,” Chiang says. Seasonal storage is important too, he adds, especially with increasing distance north of the equator, where the amount of sunlight varies more widely from summer to winter.

Chiang says this could be the first technology to compete, in cost and energy density, with pumped hydroelectric storage systems, which provide most of the energy storage for renewables around the world but are very restricted by location.

“The energy density of a flow battery like this is more than 500 times higher than pumped hydroelectric storage. It’s also so much more compact, so that you can imagine putting it anywhere you have renewable generation,” Chiang says.