Lachlanmoss

In this video Max More talks about the will to live and his personal journey through life and death. He also explains the philosophy, science, and desire behind cryonics.

An internationally recognized advocate of the effective and ethical use of technology for life extension and cryopreservation, Dr. More brings experience in running non-profit organizations, many years of analyzing and writing about business organizations, and a long commitment to Alcor’s mission. More joined Alcor in 1986 as its 67th member, founded Alcor-UK (originally Mizar Limited) in the same year, and has participated in several cryopreservations. Dr. More co-founded and until 2007 acted as Chairman of Extropy Institute, an educational non-profit organization that created the modern “transhumanist” movement, whose goals centrally include extending healthy human life span.

More has a degree in Philosophy, Politics, and Economics from St. Anne’s College, Oxford University (1984-87). He was awarded a Dean’s Fellowship in Philosophy in 1987 by the University of Southern California. He studied and taught philosophy at USC with an emphasis on philosophy of mind, ethics, and personal identity, completing his Ph.D. in 1995, with a dissertation that examined issues including the nature of death, and what it is about each individual that continues despite great change over time.

Marvin Minsky, “the father of artificial intelligence”, said of Dr. More: “We have a dreadful shortage of people who know so much, can both think so boldly and clearly, and can express themselves so articulately.”

LONDON – Power-generating stations worldwide release 12 billion tons of carbon dioxide every year as they burn coal, oil or natural gas; home and commercial heating plants release another 11 billion tons. A team of Dutch scientists has a use for it.

The life-cycle of a Sun-like star from protostar (left side) to red giant (near the right side) to white dwarf (far right). Credit: ESO/M. Kornmesser

If you want a picture of how you’ll look in 30 years, youngsters are told, look at your parents. The same principle is true of astronomy, where scientists compare similar stars in different age groups to see how they progress.

We have a special interest in learning how the Sun will look in a few billion years because, you know, it’s the main source of energy and life on Earth. Newly discovered HIP 102152 could give us some clues. The star is four billion years older than the sun, but so close in composition that researchers consider it almost like a twin.

(...)
Read the rest of Double Vision: Scientists Spot An Elder ‘Twin’ To the Sun (417 words)

© Elizabeth Howell for Universe Today, 2013. | Permalink | 3 comments |
Post tags: alien planets, European Southern Observatory, exoplanets, HIP 102152, lithium, telescope, Very Large Telescope

Feed enhanced by Better Feed from Ozh

Every so often in the vast cosmos something exciting happens in one of the relatively few places that humans happen to watch closely. Like a rare bird touching down for a bath in the Trevi Fountain, such serendipitously placed exotica produces a wealth of witnesses and plenty of photographic documentation.

Unlike conventional semiconductors, graphene cannot be switched off, a problem that threatens to scupper its use in future generations of transistors. Now physicists think they’ve found a solution.

The writing is on the wall for the silicon chip. Transistors have been shrinking for the last half a century but they cannot get smaller forever. Most industry pundits think that the downscaling of silicon chip technology cannot extend much beyond 2026. The big question, of course, is what will replace it.

Elements of a flow battery (Credit: Felice Frankel)

MIT researchers have engineered a new rechargeable flow battery that doesn’t rely on expensive membranes to generate and store electricity. The device, they say, may one day enable cheaper, large-scale energy storage.

The palm-sized prototype generates three times as much power per square centimeter as other membraneless systems — a power density that is an order of magnitude higher than that of many lithium-ion batteries and other commercial and experimental energy-storage systems.

The device stores and releases energy in a device that relies on a phenomenon called laminar flow: Two liquids are pumped through a channel, undergoing electrochemical reactions between two electrodes to store or release energy. Under the right conditions, the solutions stream through in parallel, with very little mixing. The flow naturally separates the liquids, without requiring a costly membrane.

The reactants in the battery consist of a liquid bromine solution and hydrogen fuel. The group chose to work with bromine because the chemical is relatively inexpensive and available in large quantities, with more than 243,000 tons produced each year in the United States.

In addition to bromine’s low cost and abundance, the chemical reaction between hydrogen and bromine holds great potential for energy storage. But fuel-cell designs based on hydrogen and bromine have largely had mixed results: Hydrobromic acid tends to eat away at a battery’s membrane, effectively slowing the energy-storing reaction and reducing the battery’s lifetime.

To circumvent these issues, the team landed on a simple solution: Take out the membrane.

“This technology has as much promise as anything else being explored for storage, if not more,” says Cullen Buie, an assistant professor of mechanical engineering at MIT. “Contrary to previous opinions that membraneless systems are purely academic, this system could potentially have a large practical impact.”

“Here, we have a system where performance is just as good as previous systems, and now we don’t have to worry about issues of the membrane,” Bazant says. “This is something that can be a quantum leap in energy-storage technology.”

Possible boost for solar and wind energy 

Low-cost energy storage has the potential to foster widespread use of renewable energy, such as solar and wind power. To date, such energy sources have been unreliable: Winds can be capricious, and cloudless days are never guaranteed. With cheap energy-storage technologies, renewable energy might be stored and then distributed via the electric grid at times of peak power demand.

“Energy storage is the key enabling technology for renewables,” Buie says. “Until you can make [energy storage] reliable and affordable, it doesn’t matter how cheap and efficient you can make wind and solar, because our grid can’t handle the intermittency of those renewable technologies.”

By designing a flow battery without a membrane, Buie says the group was able to remove two large barriers to energy storage: cost and performance. Membranes are often the most costly component of a battery, and the most unreliable, as they can corrode with repeated exposure to certain reactants.

Braff built a prototype of a flow battery with a small channel between two electrodes. Through the channel, the group pumped liquid bromine over a graphite cathode and hydrobromic acid under a porous anode. At the same time, the researchers flowed hydrogen gas across the anode. The resulting reactions between hydrogen and bromine produced energy in the form of free electrons that can be discharged or released.

The researchers were also able to reverse the chemical reaction within the channel to capture electrons and store energy — a first for any membraneless design.

In experiments, Braff and his colleagues operated the flow battery at room temperature over a range of flow rates and reactant concentrations. They found that the battery produced a maximum power density of 0.795 watts of stored energy per square centimeter.

More storage, less cost

In addition to conducting experiments, the researchers drew up a mathematical model to describe the chemical reactions in a hydrogen-bromine system. Their predictions from the model agreed with their experimental results — an outcome that Bazant sees as promising for the design of future iterations.

“We have a design tool now that gives us confidence that as we try to scale up this system, we can make rational decisions about what the optimal system dimensions should be,” Bazant says. “We believe we can break records of power density with more engineering guided by the model.”

Yury Gogotsi, a professor of materials science and engineering at Drexel University, says eliminating the membrane is the next step toward scalable, inexpensive energy storage. The group’s design, he says, will help engineers better understand the physics of membraneless systems.

“You cannot have an inexpensive energy-storage system by piling up tens of thousands of individual small cells, like cellphone or computer batteries,” says Gogotsi, who did not contribute to the research. “As any new technology, the laminar flow battery will need time to prove its viability. It’s like a newborn baby — we’ll only know what the technology is good for after a few years.”

According to preliminary projections, Braff and his colleagues estimate that the membraneless flow battery may produce energy costing as little as $100 per kilowatt-hour — a goal that the U.S. Department of Energy has estimated would be economically attractive to utility companies. (“The current cost of EV batteries is about $650/kWh, which is much greater than an estimated target of $125/kWh of usable energy for widespread implementation,” according to a DOE Funding Opportunity Announcement — see Ref. 2 below.) (“kWh” here refers to usable energy, i.e., battery capacity, rather than usage.)

US Department of Energy Funding Opportunity Announcement, Energy Innovation Hub – Batteries and Energy Storage, DE-FOA-0000559, February 2012, https://www.fedconnect.net/FedConnect/?doc=DE-FOA-0000559&agency=DOE Amendment 000001

“You can do so much to make the grid more efficient if you can get to a cost point like that,” Braff says. “Most systems are easily an order of magnitude higher, and no one’s ever built anything at that price.”

UPDATE 8/20/2013: Added explanation of “$100 per kilowatt-hour.”

I’ve met a lot of people and learned a lot while traveling Europe the past several weeks. Of all the things I have had to explain to fellow travels as not only an American – but a Texan – by far the most frustrating thing is our stubborn refusal to embrace the metric system. I can confidently argue the finer points of how the use of y’all and the plural form all y’all are descriptive and have a place in the American lexicon. I take pleasure in explaining the intricacies of chicken fried foods.

Set in the near future, “I’s” is a small story of humanity on the precipice of an unimaginable transformation in our civilization.

In the next 20 years, it is likely that humankind will develop an artificial intelligence with mental abilities greater than our own. That idea has been fodder for many films, from 2001 to the Terminator to The Matrix.

But those films missed a much greater possibility.

As author and mathematician Vernor Vinge first suggested - if we create an intelligence greater than our own, it can develop an intelligence even greater than itself, perhaps in a matter of only days. This resulting exponential intelligence escalation has come to be known as the Singularity. Once we start the process, it is very unlikely that we can stop it, and we have no idea what a hyper intelligence could - or would - do.

An artist’s concept of a rocky world orbiting a red dwarf star. (Credit: NASA/D. Aguilar/Harvard-Smithsonian center for Astrophysics).

Hunters of alien life may have a new and unsuspected niche to scout out.

A recent paper submitted by Associate Professor of Astronomy at Columbia University Kristen Menou to the Astrophysical Journal suggests that tidally-locked planets in close orbits to M-class red dwarf stars may host a very unique hydrological cycle. And in some extreme cases, that cycle may cause a curious dichotomy, with ice collecting on the farside hemisphere of the world, leaving a parched sunward side. Life sprouting up in such conditions would be a challenge, experts say, but it is — enticingly — conceivable.

(...)
Read the rest of Water-Trapped Worlds Possible Around Red Dwarf Stars? (964 words)

© David Dickinson for Universe Today, 2013. | Permalink | 8 comments |
Post tags: exoplanets, Extrasolar Planets, goldilocks zone, habitable zone, life in the universe, red dwarf star

Feed enhanced by Better Feed from Ozh

The insertion of one gene can muzzle the extra copy of chromosome 21 that causes Down’s syndrome, according to a study published today in Nature . The method could help researchers to identify the cellular pathways behind the disorder's symptoms, and to design targeted treatments.

By Andrew Nelson
Chief Operating Officer,
XCOR Aerospace

Just a quick note while I have a moment to stop and reflect in the thick of NSRC 2013. Specifically, I want to address some new rules being proposed by the US State Department on export controls for manned suborbital space vehicles designed for commercial spaceflight.

At the end of May, the Department of State published a Notice of Proposed Rulemaking (or NPRM) Rule 78 FR 31 444 (pdf)– that did a great thing. The DoS proposed a move of commercial satellites from the US Department of Defense (DoD) Munitions List to the Department of Commerce’s commerce control list (CCL).  This is a great step for the industry. Since the time commercial satellites were placed on the munitions list in 1999, the commercial satellite industry was almost wiped out.

As the Aerospace Industries Association clearly illustrates in its fact sheet on US Satellite Manufacturing Job Losses (pdf), the US commercial satellite industry lost over 250,000 jobs. Market share dropped from a dominant position greater than 60%, down to bare relevance at under 30% by 2008 (and less today). The impact on the US launcher community was greater, as it is now practically non-existent. The US does not launch commercial satellites, they are launched elsewhere. Again, more than a quarter of a million jobs were lost mainly due to these restrictions.

Unfortunately, there were some “not so good” inclusions in the Department of State NPRM … it has explicitly proposed to put manned commercial space flight vehicles on the Department of Defense Munitions List. This is the same backward path provided to the US satellite manufacturing and launch community two decades ago that almost decimated that industry.

However, even before we can achieve a meaningful sized global market, and dominate it with US companies, there is the real possibility that we will be hampered before the market is fully opened. The benefits that have a real potential of not being realized are high tech job creation in rural, underserved, and hard hit regions of our country (by necessity, these vehicles are flown in remote areas); creation of a global, multi-billion dollar suborbital space-science research and personal spaceflight industry led by US companies; and the very large influence that these operations will have on our children through enhanced STEM opportunities. We will be turning over the lead to non-US companies.

Let’s push together to move the proposed rules in a better direction. Write to the State Department before July 8^th and tell them to move suborbital manned vehicles to the Commerce Control List.

Via the U.S. Department of State:

“Interested parties may submit comments within 45 days of the date of publication by one of the following methods.

• Email DDTCResponseTeam@state.gov with the subject line ‘‘ITAR Amendment—USML Category XV and Defense Services.’’
• Internet: At www.regulations.gov, search for this notice by using this rule’s RIN (1400–AD33).”

Please follow Parabolic Arc on Facebook and Twitter.

The globular cluster NGC 6388. Blue stragglers may be seen around the edges, while others are hidden within the central core. Credit: ESO

A unique and enigmatic variety of stars known as blue stragglers appear to defy the normal stellar aging process. Discovered in globular clusters, they appear much younger than the rest of the stellar population. Since their discovery in 1953, astronomers have been asking the question: how do these stars regain their youth?

For years, two theories have persisted. The first theory suggests that two stars collide, forming a single more massive star. The second theory proposes that blue stragglers emerge from binary pairs. As the more massive star evolves and expands, it blows material onto the smaller star. In both theories, the star grows steadily more massive and bluer – it regains its youth.

But now, a surprising finding may lend credence to the second theory. Astronomers at the Nicolaus Copernicus Astronomical Center in Poland recently observed a blue straggler caught in the midst of forming!

(...)
Read the rest of A Rare Opportunity to Watch a Blue Straggler Forming (403 words)

© Shannon Hall for Universe Today, 2013. | Permalink | 2 comments |
Post tags: binary star systems, Blue Stragglers

Feed enhanced by Better Feed from Ozh

A fish swims into an enclosure and disappears, while the pondweed behind remains perfectly visible. A cat climbs into a glass box and vanishes, and again the scene behind the box remains visible through the glass. This latest addition to the science of invisibility cloaks is one of the simplest implementations so far, but there’s no denying its striking impact.

Phil Ivey makes a deep run at the WSOP, and Daniel Negreanu played the best hand ever. It’s all in the Tuesday edition of PTP’s Hit and Run.

WSOP updates: Get up to speed with the World Series of Poker here, including Ivey’s bid for braclet No. 10.

Also at the WSOP:
–Who is not at the WSOP?
–Joe Cada is doing well.
–Mickey Petersen blogs about winning streaks and the WSOP.
–Tom Schneider provides some insight into his third bracelet victory.
–Photo bloggin’.

Best hand ever?: PokerStars dubs the hand below, involving Daniel Negreanu, as the best ever in PokerStars history. Agree, disagree? More here. Watch and judge:

Quick hitters:
–Get up to date with PokerStars’ 100 Billionth Hand promotion.
–Is this Bank of Timex thing isn’t going to happen? Mike McDonald tweets. See what all the Twitterverse was atwitter about before:

–The latest Sunday Million:

–Gavin Griffin answers questions from players.
–You can learn six-max with Felix ‘xflixx’ Schneiders via PokerStars at PokerSchoolOnline.
–Maria Ho is in a new poker reality show.

Hand-held device for extracting DNA (credit: UW/NanoFacture/KNR)

University of Washington engineers and NanoFacture, a Bellevue, Wash., company, have created a device that can extract human DNA from fluid samples in a simpler, more efficient and environmentally friendly way than conventional methods.

The device will give hospitals and research labs a much easier way to separate DNA from human fluid samples, which will help with genome sequencing, disease diagnosis and forensic investigations.

Separating DNA from bodily fluids is a cumbersome process that’s become a bottleneck as scientists make advances in genome sequencing, particularly for disease prevention and treatment. The market for DNA preparation alone is about $3 billion each year.

Conventional methods use a centrifuge to spin and separate DNA molecules or strain them from a fluid sample with a micro-filter, but these processes take 20 to 30 minutes to complete and can require excessive toxic chemicals.

A close-up view of the portable device (credit: UW/NanoFacture/KNR)

UW engineers designed microscopic probes that dip into a fluid sample – saliva, sputum or blood – and apply an electric field within the liquid. That draws particles to concentrate around the surface of the tiny probe. Larger particles hit the tip and swerve away, but DNA-sized molecules stick to the probe and are trapped on the surface. It takes two or three minutes to separate and purify DNA using this technology.

“This simple process removes all the steps of conventional methods,” said Jae-Hyun Chung, a UW associate professor of mechanical engineering who led the research.

The hand-held device can clean four separate human fluid samples at once, but the technology can be scaled up to prepare 96 samples at a time, which is standard for large-scale handling.

The tiny probes, called microtips and nanotips, were designed and built at the UW in a micro-fabrication facility where a technician can make up to 1 million tips in a year, which is key in proving that large-scale production is feasible, Chung said.

Engineers in Chung’s lab also have designed a pencil-sized device using the same probe technology that could be sent home with patients or distributed to those serving in the military overseas. Patients could swab their cheeks, collect a saliva sample, then process their DNA on the spot to send back to hospitals and labs for analysis.

This could be useful as efforts ramp up toward sequencing each person’s genome for disease prevention and treatment, Chung said.

The market for this device isn’t developed yet, but Chung’s team will be ready when it is. Meanwhile, the larger device is ready for commercialization, and its creators have started working with distributors.

A UW Center for Commercialization grant of $50,000 seeded initial research in 2008, and since then researchers have received about $2 million in funding from the National Science Foundation and the National Institutes of Health.

The movement of two stars and Proxima Centuri movement plotted to aid in the planet hunt. Credit:NASA, ESA, K. Sahu and J. Anderson (STScI), H. Bond (STScI and Pennsylvania State University), M. Dominik (University of St. Andrews), and Digitized Sky Survey (STScI/AURA/UKSTU/AAO)

Hubble is going to be looking for planets in around Proxima Centuri and the way it is going to do it is pretty VERY cool. I hope it works! It should be noted so far planets have not been detected there. Now there is a couple of opportunities to try a new technique.

Proxima Centuri is a red dwarf sun and it is also the closest Sun to our system. To have a new look for planets what they have done is to searched a star catalog and found out Proxima Centuri will pass in front of two stars, the first in October 2014 and February 2016. When these events occur there will be microlensing effects lasting from a few hours to a few days.

Here’s the explanation from NASA’s Hubble page:

Astronomers will measure the mass by examining images of each of the background stars to see how far the stars are offset from their real positions in the sky. The offsets are the result of Proxima Centauri’s gravitational field warping space. The degree of offset can be used to measure Proxima Centauri’s mass. The greater the offset, the greater the mass of Proxima Centauri. If the red dwarf has any planets, their gravitational fields will produce a second small position shift.

Because Proxima Centauri is so close to Earth, the area of sky warped by its gravitation field is larger than for more distant stars. This makes it easier to look for shifts in apparent stellar position caused by this effect. However, the position shifts will be too small to be perceived by any but the most sensitive telescopes in space and on the ground. The European Space Agency’s Gaia space telescope and the European Southern Observatory’s Very Large Telescope on Mt. Cerro Paranal in Chile may be able to make measurements comparable to Hubble’s.

Overexpression in the hippocampus dentate gyrus of mice resulted in significantly delayed spatial learning and memory as measured by longer latency to reaching the platform (upper plot) compared to control group (lower plot). (Credit: Boaz Barak et al./NeuroMolecular Medicine)

In the brain, cell-to-cell communication is dependent on neurotransmitters, chemicals that aid the transfer of information between neurons.

Several proteins have the ability to modify the production of these chemicals by either increasing or decreasing their amount, or promoting or preventing their secretion. One example is tomosyn, which hinders the secretion of neurotransmitters when in abnormal amounts.

Dr. Boaz Barak of Tel Aviv University‘s Sagol School of Neuroscience, in collaboration with Prof. Uri Ashery, used a method for modifying the levels of this protein in the mouse hippocampus — the region of the brain associated with learning and memory.

They found tomosyn had a significant impact on the brain’s activity: Over-production led to a sharp decline in the ability to learn and memorize information, the researchers reported in the journal NeuroMolecular Medicine.

“This study demonstrates that it is possible to manipulate various processes and neural circuits in the brain,” says Dr. Barak, a finding which may aid in the development of therapeutic procedures for epilepsy and neurodegenerative diseases such as Alzheimer’s.

Slowing the transmission rate of information when the brain is overactive during epileptic seizures could have a beneficial effect, and readjusting the levels of tomosyn in an Alzheimer’s patient may help increase cognition and combat memory loss, he said.

A maze of memory loss

The researchers teamed up with a laboratory at the National Institutes of Health (NIH) in Baltimore to create a virus that produces the tomosyn protein. In the lab, the virus was injected into the hippocampus region in mice. Then, to test the consequences, they performed a series of behavioral tests designed to measure functions like memory, cognitive ability, and motor skills.

In one experiment, called the Morris Water Maze, mice had to learn to navigate to, and remember, the location of a hidden platform placed inside a pool with opaque water. During the first five days of testing, researchers found that the test group with an over-production of tomosyn had a significant problem in learning and memorizing the location of the platform, compared to a control group that received a placebo injection.

And when the platform was removed from the maze, the test group spent less time swimming around the area where the platform once was, indicating that they had no memory of its existence. In comparison, the control group of mice searched for the missing platform in its previous location for two or even three days after its removal, notes Dr. Barak.

These findings were further verified by measuring electrical activity in the brains of both the test group and the control group. In the test group, researchers found decreased levels of transmissions between neurons in the hippocampus, a physiological finding that may explain the results of the behavioral tests.

Correcting neuronal processes by modifying brain proteins

In the future, Dr. Barak believes that the ability to modify proteins directly in the brain will allow for more control over brain activities and the correction of neurodegenerative processes, such as providing stricter regulation in neuronal activity for epileptic patients or stimulating neurotransmitters to help with learning and memory loss in Alzheimer’s patients.

A separate study conducted by the researchers supports that premise. It demonstrates that mouse models for Alzheimer’s disease do have an over-production of tomosyn in the hippocampus region, so countering the production of this protein could have a beneficial effect.

Now Dr. Barak and Prof. Ashery are developing a method for artificially decreasing levels of the protein. “We hypothesize that with an under-production in tomosyn, the mice will show a marked improvement in their cognitive performance in behavioral testing,” he said

(Credit: iStockphoto)

Researchers at the Stanford University School of Medicine have found that a naturally occurring protein secreted only in discrete areas of the mammalian brain may act as a Valium-like brake on certain types of epileptic seizures.

The protein is known as diazepam binding inhibitor, or DBI. It calms the rhythms of a key brain circuit and so could prove valuable in developing novel, less side-effect-prone therapies not only for epilepsy but possibly for anxiety and sleep disorders, too. The researchers’ discoveries is published May 30 in Neuron.

“This is one of the most exciting findings we have had in many years,” said John Huguenard, PhD, professor of neurology and neurological sciences and the study’s senior author. “Our results show for the first time that a nucleus deep in the middle of the brain generates a small protein product, or peptide, that acts just like benzodiazepines.” This drug class includes not only the anti-anxiety compound Valium (generic name diazepam), first marketed in 1965, but its predecessor Librium, discovered in 1955, and the more recently developed sleep aid Halcyon.

Valium, which is notoriously addictive, prone to abuse and dangerous at high doses, was an early drug treatment for epilepsy, but it has fallen out of use for this purpose because its efficacy quickly wears off and because newer, better anti-epileptic drugs have come along.

For decades, DBI has also been known to researchers under a different name: ACBP. In fact, it is found in every cell of the body, where it is an intracellular transporter of a metabolite called acyl-CoA. “But in a very specific and very important brain circuit that we’ve been studying for many years, DBI not only leaves the cells that made it but is — or undergoes further processing to become — a natural anti-epileptic compound,” Huguenard said. “In this circuit, DBI or one of its peptide fragments acts just like Valium biochemically and produces the same neurological effect.”

Marijuana-mimicking substances in the brain

Other endogenous (internally produced) substances have been shown to cause effects similar to psychoactive drugs. In 1974, endogenous proteins called endorphins, with biochemical activity and painkilling properties similar to that of opiates, were isolated. A more recently identified set of substances, the endocannabinoids, mimic the memory-, appetite- and analgesia-regulating actions of the psychoactive components of cannabis, or marijuana.

DBI binds to receptors that sit on nerve-cell surfaces and are responsive to a tiny but important chemical messenger, or neurotransmitter, called GABA. The roughly one-fifth of all nerve cells in the brain that are inhibitory mainly do their job by secreting GABA, which binds to receptors on nearby nerve cells, rendering those cells temporarily unable to fire any electrical signals of their own.

Benzodiazepine drugs enhance GABA-induced inhibition by binding to a different site on GABA receptors from the one GABA binds to. That changes the receptor’s shape, making it hyper-responsive to GABA. These receptors come in many different types and subtypes, not all of which are responsive to benzodiazepines. DBI binds to the same spot to which benzodiazepines bind on benzodiazepine-responsive GABA receptors. But until now, exactly what this means has remained unclear.

Huguenard, along with postdoctoral scholar and lead author Catherine Christian, PhD, and several Stanford colleagues zeroed in on DBI’s function in the thalamus, a deep-brain structure that serves as a relay station for sensory information, and which previous studies in the Huguenard lab have implicated on the initiation of seizures.

The researchers used single-nerve-cell-recording techniques to show that within a GABA-secreting nerve-cell cluster called the thalamic reticular nucleus, DBI has the same inhibition-boosting effect on benzodiazepine-responsive GABA receptors as do benzodiazepines. Using bioengineered mice in which those receptors’ benzodiazepine-binding site was defective, they showed that DBI lost its effect, which Huguenard and Christian suggested makes these mice seizure-prone.

In another seizure-prone mouse strain in which that site is intact but the gene for DBI is missing, the scientists saw diminished inhibitory activity on the part of benzodiazepine-responsive GABA receptors. Re-introducing the DBI gene to the brains of these mice via a sophisticated laboratory technique restored the strength of the GABA-induced inhibition.

In normal mice, a compound known to block the benzodiazepine-binding site weakened these same receptors’ inhibitory activity in the thalamic reticular nucleus, even in the absence of any administered benzodiazepines. This suggested that some naturally occurring benzodiazepine-like substance was being displaced from the benzodiazepine-binding site by the drug. In DBI-gene-lacking mice, the blocking agent had no effect at all.

Huguenard’s team also showed that DBI has the same inhibition-enhancing effect on nerve cells in an adjacent thalamic region — but also that, importantly, no DBI is naturally generated in or near this region; in the corticothalamic circuit, at least, DBI appears to be released only in the thalamic reticular nucleus. So, the actions of DBI on GABA receptors appear to be tightly controlled to occur only in specific brain areas.

Huguenard doesn’t know yet whether it is DBI per se, or one of its peptide fragments (and if so which one), that is exerting the active inhibitory role. But, he said, by finding out exactly which cells are releasing DBI under what biochemical circumstances, it may someday be possible to develop agents that could jump-start and boost its activity in epileptic patients at the very onset of seizures, effectively nipping them in the bud.

The study received funding from the National Institute of Neurological Disorders and Stroke (grants NS034774, NS006477 and T32NS007280), the Epilepsy Foundation and a Katharine McCormick Advanced Postdoctoral Fellowship at the School of Medicine.

MIT engineers have created synthetic biology circuits that can perform analog computations such as taking logarithms and square roots in living cells (cartoon) (credit: Ramiz Daniel et al./MIT)

By combining existing genetic “parts,” or engineered genes, in novel ways, MIT engineers have transformed bacterial cells into living calculators that can compute logarithms, divide, and take square roots, using three or fewer genetic parts.

The circuits perform those calculations in an analog fashion by exploiting natural biochemical functions that are already present in the cell rather than by reinventing them with digital logic.

This makes them more efficient than the digital circuits pursued by most synthetic biologists, according to MIT engineers Rahul Sarpeshkar and Timothy Lu, the two senior authors on the paper describing the circuits in the May 15 online edition of Nature.

“In analog you compute on a continuous set of numbers, which means it’s not just black and white, it’s gray as well,” says Sarpeshkar, an associate professor of electrical engineering and computer science and the head of the Analog Circuits and Biological Systems group at MIT

Analog computation would be particularly useful for designing cellular sensors for pathogens or other molecules, the researchers say. Analog sensing could also be combined with digital circuits to create cells that can take a specific action triggered by a threshold concentration of certain molecules.

“You could do a lot of upfront sensing with the analog circuits because they’re very rich and a relatively small amount of parts can give you a lot of complexity, and have that output go into a circuit that makes a decision — is this true or not?” says Lu, an assistant professor of electrical engineering and computer science and biological engineering.

Analog advantages 

Sarpeshkar has previously identified thermodynamic similarities between analog transistor circuits and the chemical circuits that take place inside cells. In 2011, he took advantage of those similarities to model biological interactions between DNA and proteins in an electronic circuit, using only eight transistors.

In the new Nature paper, Sarpeshkar, Lu and colleagues have done the reverse — mapping analog electronic circuits onto cells. Sarpeshkar has long advocated analog computing as a more efficient alternative to digital computation at the moderate precision of computation seen in biology. These analog circuits are efficient because they can take in a continuous range of inputs, and they exploit the natural continuous computing functions that are already present in cells. In the case of cells, that continuous input might be the amount of glucose present. In transistors, it’s a range of continuous input currents or voltages.

Digital circuits, meanwhile, represent every value as zero or one, ignoring the range of possibilities in between. This can be useful for creating circuits that perform logic functions such as AND, NOT and OR inside cells, which many synthetic biologists have done. These circuits can reveal whether or not a threshold level of a certain molecule is present, but not the exact amount of it.

Digital circuits also require many more parts, which can drain the energy of the cell hosting them. “If you build too many parts to make some function, the cell is not going to have the energy to keep making those proteins,” Sarpeshkar says.

Doing the math

Complex analog computation can be implemented by composing synthetic gene circuits. Here, an adder is built
by engineering two wide-dynamic-range, positive-slope logarithm circuits (modules outlined in red) to produce a common output, which is summed to yield the overall output. (credit: Ramiz Daniel et al./MIT/Nature)

To create an analog adding or multiplying circuit that can calculate the total quantity of two or more compounds in a cell, the researchers combined two circuits, each of which responds to a different input. In one circuit, a sugar called arabinose turns on a transcription factor that activates the gene that codes for green fluorescent protein (GFP). In the second, a signaling molecule known as AHL also turns on a gene that produces GFP. By measuring the total amount of GFP, the total amount of both inputs can be calculated.

To subtract or divide, the researchers swapped one of the activator transcription factors with a repressor, which turns off production of GFP when the input molecule is present. The team also built an analog square root circuit that requires just two parts, while a recently reported digital synthetic circuit for performing square roots had more than 100.

“Analog computation is very efficient,” Sarpeshkar says. “To create digital circuits at a comparable level of precision would take many more genetic parts.”

Another of the team’s circuits can perform division by calculating the ratio of two different molecules. Cells often perform this kind of computation on their own, which is critical for monitoring the relative concentrations of molecules such as NAD and NADH, which are frequently converted from one to the other as they help other cellular reactions take place.

“That ratio is important for controlling a lot of cellular processes, and the cell naturally has enzymes that can recognize those ratios,” Lu says. “Cells can already do a lot of these things on their own, but for them to do it over a useful range requires extra engineering.”

That extra engineering included modifying the circuits so that they can compute with inputs over a range of 1 to 10,000 — much wider than the range of a naturally occurring cell circuit.

The researchers are now trying to create analog circuits in nonbacterial cells, including mammalian cells. They are also working on expanding the library of genetic parts that can be incorporated into the circuits. “Right now we’re using three of the most commonly used transcription factors in biology, but we’d like to do this with additional parts and make this a generalizable platform so everyone else can use it,” Lu says.

“We have just scratched the surface of what sophisticated analog feedback circuits can do in living cells,” says Sarpeshkar, whose lab is working on building further new analog circuits in cells. He believes the new approach of what he terms “analog synthetic biology” will create a new set of fundamental and applied circuits that can dramatically improve the fine control of gene expression, molecular sensing, computation and actuation.

The research was funded by MIT Lincoln Laboratory, the Office of Naval Research and the National Science Foundation.

In its push for putting zero-emission cars on the road, the Department of Energy is launching new programs to study the infrastructure needed to run vehicles on hydrogen.

Artist’s concept of “hot Jupiter” exoplanet HD 149026b (NASA/JPL-Caltech)

Overheated and overinflated, hot Jupiters are some of the strangest extrasolar planets to be discovered by the Kepler mission… and they may be even more exotic than anyone ever thought. A new model proposed by Florida Gulf Coast University astronomer Dr. Derek Buzasi suggests that these worlds are intensely affected by electric currents that link them to their host stars. In Dr. Buzasi’s model, electric currents arising from interactions between the planet’s magnetic field and their star’s stellar wind flow through the interior of the planet, puffing it up and heating it like an electric toaster.

In effect, hot Jupiters are behaving like giant resistors within exoplanetary systems.

(...)
Read the rest of Flying Space Toasters: Electrified Exoplanets Really Feel the Heat (524 words)

© Jason Major for Universe Today, 2013. | Permalink | No comment |
Post tags: AAS222, electricity, exoplanets, hot jupiter, Kepler, stellar wind

Feed enhanced by Better Feed from Ozh

Ace magician Luís de Matos recently posted this photo on his facebook post (and David B brought it to my attention):

I think it is an interesting idea. Would it be good for charities to ask people to specify their religion when they make an online donation, and then show the results per head per religion? Do you think it would encourage people to give more?

A mirror ball–the most perfect test particle ever placed in orbit–should help Italian scientists measure an exotic effect predicted by general relativity

Marijuana is more popular and accessible in the U.S. than any other street drug. In national surveys, 48 percent of Americans say they have tried it, and 6.5 percent of high school seniors admit to daily use. So it was not too surprising when two states, Washington and Colorado, became the first to legalize recreational marijuana in the November 2012 general election, albeit in limited quantity, for anyone over the age of 21. Activists expect that similar measures will soon win approval in other parts of the country.