Tag Archives: Yale University

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Scientists examine over 1,000 chemicals from fracking fluids: many linked to reproductive or development toxicity

The indispensable chemical mixture that allows the industry to fracture rock and release the gas trapped inside is basically a black box. More than 1,000 chemicals are used in the fracking fluid, but a paper published in the Journal of Exposure Science and Environmental Epidemiology found toxicity information was lacking for 76% of them. In other words, these could be harmless or dangerous. there’s no way to know at this point. Concerning the rest — about 240 substances — the researchers found evidence that  suggests reproductive toxicity for 103 (43%), developmental toxicity for 95 (40%), and both for 41 (17%).

fracking fire

Image: YouTube

Substances mentioned in the study include arsenic, benzene, cadmium, lead, formaldehyde, chlorine, and mercury. Of the 240 analyzed substances, 67 were particularly worrisome since these had an existing federal health-based standard or guideline. Like all hazardous chemicals, it’s the dose that matters. In the right concentration, a usually toxic chemical can be harmless. The researchers from Yale University say data on whether levels of chemicals exceeded the guidelines were too limited to assess.

“This evaluation is a first step to prioritize the vast array of potential environmental contaminants from hydraulic fracturing for future exposure and health studies,” said Nicole Deziel, senior author and assistant professor of public health. “Quantification of the potential exposure to these chemicals, such as by monitoring drinking water in people’s homes, is vital for understanding the public health impact of hydraulic fracturing.”

“We focused on reproductive and developmental toxicity because these effects may be early indicators of environmental hazards. Gaps in our knowledge highlight the need to improve our understanding of the potential adverse effects associated with these compounds,” said Elise Elliott, a public health doctoral student and the paper’s first author.


Image: FracFocus

Fracking chemicals: a black box. Most drillers are not mandated to disclose the chemical makeup of fracking fluid, being treated as trade secrets.

According to Preserve the Beartooth Front, these findings from Yale echo previous research that found associations between proximity to hydraulic fracturing sites and reproductive and developmental problems. These include:

  • A 2013 Colorado study showed that exposure to frac water “could raise the risk of reproductive, metabolic, neurological and other diseases, especially in children who are exposed to EDCs [endocrine-disrupting chemicals].”
  • A 2014 Pennsylvania study looked at birth records to assess the health of infants born withina 2.5-kilometer radius of fracking sites. They found that proximity to fracking increased the likelihood of low birth weight by more than half.
  • A 2014 Colorado study examined the connection between how close a mother is to natural gas drilling and birth outcomes in a study of 124,842 births in rural Colorado between 1996 and 2009. The study shows an association between density and proximity of natural gas wells within a 10-mile radius of maternal residence and an increase of as much as 30% in the prevalence of congenital heart defects.

Earlier this year, the  U.S. Environmental Protection Agency (EPA) released a report in which it analyzed more than 39,000 FracFocus disclosures in the last two years.  The report found that the median number of chemical additives per fracking job was 14. Hydrochloric acid, methanol, and hydrotreated light petroleum distillates were the most common additives, being reported in 65 percent of all disclosures. Even in low doses, these are known to cause skin irritation, chemical burns, headaches and blurred vision.

In the past ten years, America has lived through what experts herald as the “shale boom” – a massive development of hydraulic fracturing wells to the point that today the U.S. has become the #1 crude oil and natural gas producer in the world. Nine out of ten wells in the U.S. are now fracking wells.


Essentially, hydraulic fracking wells pump a mixture of chemicals, sand and water some 2 miles deep into the ground. The pressure breaks down rock and releases the hydrocarbons previously trapped for millions of years.

While fracking gave the U.S. a huge leverage, both economical and tactical, critics have voiced a number of valid concerns. These include air pollution, huge amounts of wastewater, bedrock fracturing that leads to earthquakes, and — maybe most worrisome — the potential for groundwater and aquifer contamination with hazardous chemicals. There are many other concerns, as well.

Researchers at University of Texas at Arlington conducted tests on more than 100 water wells in Texas and found 30% of these contained ‘alarming’ amounts of arsenic, enough to be considered carcinogenic and seriously threatening human health. These contaminated wells were found in the vicinity of known fracking sites and prior to drilling these were found to be free of arsenic or at least far from the concentrations we’re seeing now.

Today, however, there is no evidence that might directly link fracking to contaminated water, even though many people can now light their tap water on fire after fracking wells were developed in their vicinity. When Stanford researchers traced back methane leaks from contaminated drinking water in Pennsylvania and Texas to shale gas wells, they did not find a link between the contamination and the technique used to drill for shale gas itself. Instead, the researchers concluded that well integrity is the main driver for the contamination.

With good and bad, we need more long-term research on the matter to establish whether or not fracking is worth it. Frack now, ask questions later is not a wise course of action.

Update: corrected sub-heading citing fracking chemical as undisclosed and protected by patent laws.

The Number of Trees has Halved Since Human Civilization Emerged

Today, the Earth has approximately 3 trillion trees left standing – about 422 per person – but we’ve already cut 46% of them.

Branching out


Using a mixture of satellite imagery, forest inventories and supercomputer technologies, an international team led by Yale researchers conducted the biggest survey ever on trees, mapping them globally at a square kilometer level. The researchers also used projected maps of current and historic forest cover, which were provided by the United Nations Environment Programme to see how much tree loss has occurred over time. Their results showed that there are more trees on Earth than was previously estimated, but we’ve still destroyed a big chunk of total trees: almost half. That’s already starting to take its toll.

“We have nearly halved the number of trees on the planet and we have seen the impacts on climate and human health as a result,” said Thomas Crowther, post-doctoral fellow at Yale University’s school of forestry and environmental studies (F&ES) and lead author of the study.

Indeed, we generally take trees as granted, and we often forget just how important their are for the planet – not just in terms of biodiversity, but in terms of climate, soil stability and many others. The environmental services that trees provide are inestimable.

“They store huge amounts of carbon, are essential for the cycling of nutrients, for water and air quality, and for countless human services. Yet you ask people to estimate, within an order of magnitude, how many trees there are and they don’t know where to begin,” he said, adding he was “certainly surprised” to find the estimate was in the trillions. Trees are among the most prominent and critical organisms on Earth yet we are only recently beginning to comprehend their global extent and distribution,” Crowther added.



Tree populations have remained relatively stable and constant before the human effect started kicking in. We’ve been cutting trees at an enormous rate, especially in areas like the Amazon forests in South America, but many forests in Asia, Europe and North America have also been decimated.

Trees and humans

To say that there are 422 trees per person on Earth is, while true, pretty misleading. The tree density varies greatly across continents and even countries, with the highest tree densities in the sub-arctic regions of Russia, Scandinavia and North America. In terms of total tree cover, South America still reigned supreme though, home to 43% of the world’s trees. In the UK for example, researchers found more than three billion trees, or around 47 per person, while in Ireland there are some 709 million trees, or 154 per person. That means that the trees/person rate in the UK is 10 times lower than the global average, and similar figures are reported for most of the developed world.

“The diverse array of data available today allowed us to build predictive models to estimate the number of trees at each location around the globe,” said postdoctoral student Henry Glick.

The census won’t just help us understand how many trees there are in the world, but inform scientists about the structure of forest ecosystems in different regions and calculate the amount of damage we’ve already done – and what we should do if we want to repair it; essentially, we are now the main driver controlling tree spread and density.

“The scale of human impact is astonishing,” says Thomas Crowther, an ecologist now at the Netherlands Institute of Ecology in Wageningen who led the study while at Yale University in New Haven, Connecticut. “Obviously we expected humans would have a prominent role, but I didn’t expect that it would come out as the as the strongest control on tree density.”


The most worrying fact is that we’ve been stunting tree development especially in places where we’d expect them to thrive – in warm, moist regions. Farming and deforestation often go hand in hand, as do deforestation and ecosystem destruction. The effects of cutting down trees and forests are long reaching and difficult to grasp, but one thing’s for sure: if we continue with the ‘business as usual model’, we’re going to be doing irreparable damage, and everyone on this planet, including us, will have to pay.

Journal Reference: Crowther, T. W. et al. Nature http://dx.doi.org/10.1038/nature14967 (2015).

Snakes evolved on land, possibly with toes and feet

A new analysis conducted by Yale researchers revealed that the first snakes may have actually evolved on land, not in water. These proto-snakes were likely night hunters that might have had hind legs and even toes.

“We generated the first comprehensive reconstruction of what the ancestral snake was like,” said Allison Hsiang, lead author the study published online May 19 in the journal BMC Evolutionary Biology. Hsiang is a postdoctoral researcher in Yale’s Department of Geology and Geophysics.

Image via Smithsonian.

Snakes emerged about 128.5 million years ago, during the early Cretaceous. The Cretaceous was a period with a relatively warm climate, with high sea levels and numerous shallow inland seas. Some paleontologists proposed that snakes actually evolved in these seas, ultimately differentiating in the over 3,000 species we see today.

However, this study claims otherwise. Researchers integrated genetic sequencing and fossil analysis, adding it to the anatomical comparison of 73 lizard and snake species. With this, they believe they’ve created the most comprehensive snake family tree to date. Furthermore, they propose that ancestral snakes had sharp, needle-like teeth with which they grabbed small, rodent-like creatures and swallowed them whole.

“We infer that the most recent common ancestor of all snakes was a nocturnal, stealth-hunting predator targeting relatively large prey, and most likely would have lived in forested ecosystems in the Southern Hemisphere,” Hsiang said.

But it gets even better – according to their analysis, the first snakes also had tiny hind limbs, and even toes.

“Our analyses suggest that the most recent common ancestor of all living snakes would have already lost its forelimbs, but would still have had tiny hind limbs, with complete ankles and toes. It would have first evolved on land, instead of in the sea,” said co-author Daniel Field, a Yale Ph.D. candidate. “Both of those insights resolve longstanding debates on the origin of snakes.”

This was actually the most surprising result for paleontologists, but the science seems to back it up.

“I was most amazed by how strongly we inferred that the common ancestor retained hind limbs,” Field said. “Sometimes evolution plays out in unexpected and strange ways,” he added. “We think we’ve got a strongly supported idea, and based on the mathematical reconstruction it is what is most likely to be true.”

The study was published in BMC Evolutionary Biology.

Journal Reference: Allison Y Hsiang, Daniel J Field, Timothy H Webster, Adam DB Behlke, Matthew B Davis, Rachel A Racicot and Jacques A Gauthier. The origin of snakes: revealing the ecology, behavior, and evolutionary history of early snakes using genomics, phenomics, and the fossil record, BMC Evolutionary Biology 2015. DOI: 10.1186/s12862-015-0358-5

Astronomers discover farthest galaxy yet

A team of astronomers from Yale and the University of California-Santa Cruz have looked back in time, discovering a galaxy that was formed when the Universe was only 5% of its current age. This is now the farthest, and youngest galaxy known to date.

The galaxy EGS-zs8-1 sets a new distance record. It was discovered in images from the Hubble Space Telescope’s CANDELS survey.
Credit: NASA, ESA, P. Oesch and I. Momcheva (Yale University), and the 3D-HST and HUDF09/XDF teams

When we look at something through a telescope, we don’t see it as it is now, we see it as it was when light coming from it started its journey towards us. It takes light from the Sun 8 minutes to reach us, so when we view the Sun from Earth, we see it as it was 8 minutes ago. But it took light from that galaxy billions of years to reach us, so astronomers are effectively taking a glimpse in the past.

The galaxy, named EGS-zs8-1 is one of the brightest ones we know, and it emerged just 670 million years after the Big Bang. The light from it took 13 billion years to reach us, but because the Universe is continuously expanding, it’s estimated that the galaxy is now over 30 billion light years away from us.

“It has already built more than 15% of the mass of our own Milky Way today,” said Pascal Oesch, a Yale astronomer and lead author of a study published online May 5 in Astrophysical Journal Letters. “But it had only 670 million years to do so. The universe was still very young then.” The new distance measurement also enabled the astronomers to determine that EGS-zs8-1 is still forming stars rapidly, about 80 times faster than our galaxy.

This finding is even more remarkable as only a handful galaxies from the early stages of the Universe were accurately measured in terms of distance to the Milky Way.

“Every confirmation adds another piece to the puzzle of how the first generations of galaxies formed in the early universe,” said Pieter van Dokkum, the Sol Goldman Family Professor of Astronomy and chair of Yale’s Department of Astronomy, who is second author of the study. “Only the largest telescopes are powerful enough to reach to these large distances.”

The moment at which this galaxy was captured in time was a very significant one for our Universe – it was a time when the hydrogen between galaxies was transitioning from a neutral state to an ionized state.

“It appears that the young stars in the early galaxies like EGS-zs8-1 were the main drivers for this transition, called reionization,” said Rychard Bouwens of the Leiden Observatory, co-author of the study.

The discoveries excited astronomers who believe that they will make many more similar discoveries in the future.

“Our current observations indicate that it will be very easy to measure accurate distances to these distant galaxies in the future with the James Webb Space Telescope,” said co-author Garth Illingworth of the University of California-Santa Cruz. “The result of JWST’s upcoming measurements will provide a much more complete picture of the formation of galaxies at the cosmic dawn.”

Journal Reference: P. A. Oesch, P. G. van Dokkum, G. D. Illingworth, R. J. Bouwens, I. Momcheva, B. Holden, G. W. Roberts-Borsani, R. Smit, M. Franx, I. Labbé, V. González, D. Magee. A SPECTROSCOPIC REDSHIFT MEASUREMENT FOR A LUMINOUS LYMAN BREAK GALAXY ATz= 7.730 USING KECK/MOSFIRE. The Astrophysical Journal, 2015; 804 (2): L30 DOI: 10.1088/2041-8205/804/2/L30

NASA officially starts program to look for alien life

Just after NASA researchers made the bold claim that they will find alien life in less than 20 years, the space agency has officially launched a project to look for it. The Nexus for Exoplanet System Science, or “NExSS” will be a project integrating several fields of science, aiming to better understand exoplanets with the potential to host life, as well as planet-life interactions.

An image charge with symbolism: the search for life beyond our solar system requires unprecedented cooperation across scientific disciplines. NASA’s NExSS collaboration includes those who study Earth as a life-bearing planet (lower right), those researching the diversity of solar system planets (left), and those on the new frontier, discovering worlds orbiting other stars in the galaxy (upper right).
Credits: NASA

“This interdisciplinary endeavor connects top research teams and provides a synthesized approach in the search for planets with the greatest potential for signs of life,” says Jim Green, NASA’s Director of Planetary Science. “The hunt for exoplanets is not only a priority for astronomers, it’s of keen interest to planetary and climate scientists as well.”

The study of exoplanets is a relatively new field, but has blossomed incredibly in recent years. The first exoplanet was discovered only in 1995, but in the last six years alone, we’ve managed to find over 1,000 exoplanets with thousands of additional candidates waiting to be found. Scientists are working on establishing not only the ‘Goldilocks area‘, in which planets might hold liquid water, but also the search for biosignatures, or signs of life.

Of course, in order to do this, astronomy is simply not enough – you need to understand how the chemistry and geology of an exoplanet might interact with biology, and what visible signals they give out. James Graham, a UC Berkeley professor of astronomy, and leader of the Berkeley/Stanford team explains that the project will bring together researchers from several fields.

“We’re combining techniques to discover new information about how planets form, their range of properties and what sorts of planets are most common, with the eventual goal of finding terrestrial planets and venues for life in the universe,” Graham said.

NExSS will tap into the collective expertise from each of the science communities supported by NASA’s Science Mission Directorate:

  • Earth scientists develop a systems science approach by studying our home planet.
  • Planetary scientists apply systems science to a wide variety of worlds within our solar system.
  • Heliophysicists add another layer to this systems science approach, looking in detail at how the Sun interacts with orbiting planets.
  • Astrophysicists provide data on the exoplanets and host stars for the application of this systems science framework.

The Yale University team, headed by Debra Fischer, will design new spectrometers with the stability to reach Earth-detecting precision for nearby stars. The team will also make improvements to Planet Hunters, www.planethunters.org, a web interface that allows citizen scientists to search for transiting planets in the NASA Kepler public archive data. Meanwhile, a group led by Neal Turner at NASA’s Jet Propulsion Laboratory, California Institute of Technology, will work to understand why so many exoplanets orbit close to their stars. A team at the University of Wyoming, headed by Hannah Jang-Condell, will explore the evolution of planet formation while a Penn State University team, led by Eric Ford, will strive to further understand planetary formation by investigating the bulk properties of small transiting planets and implications for their formation.

The entire thing will be coordinated by Natalie Batalha of NASA’s Ames Research Center, Dawn Gelino with NExScI, the NASA Exoplanet Science Institute, and Anthony del Genio of NASA’s Goddard Institute for Space Studies. All in all, researchers from ten universities will participate.

All in all, it’s a huge thing, with huge potential implications; it may finally help us understand whether or not we are alone in the galaxy.

Source: NASA.

This giant arthropod was the biggest creature of its time

Some 480 million years ago the seven-foot-long Aegirocassis benmoulae swam in a shallow sea covering what is today the Sahara desert. This giant arthropod, much larger than arthropods existing today, was likely the biggest creature in the world at the time, but despite its impressive appearance, it wasn’t a predator.

“It would have dwarfed anything else at the time, being twice as big as the next biggest animal — at the very least,” says Peter Van Roy, a paleontologist at Yale University and a co-author of a Nature study published today that contributes entirely new information about Aegirocassis benmoulae. “They were absolutely massive.”

illustration by Marianne Collins, ArtofFact

Back in the Ordovician, the Earth looked very different than it does today. The Cambrian explosion was already over, and life was exploring all sorts of evolutionary niches – including giant arthropods. In fact, when researchers first found a fossil of Aegirocassis, they thought they were looking at several organisms – they assumed that the appendages were actually shrimps, the toothed mouths were jellyfish, and their complete bodies were actually described as sea cucumbers. But in 1985, a group of researchers figured it out – all the bits and pieces that paleontologists thought were several creatures were actually just one organism. But there were still many questions.

“Nevertheless, the affinities of anomalocaridids remained enigmatic: it would take almost another decade before they were finally recognized as arthropods,” Van Roy says.

Interestingly enough, it was a man with no formal training in paleontology that would shed light on these creatures – a local collector in Morocco by the name of Mohamed Ben Moula. To show his gratitude, Van Roy named the creature after him.

“With a big smile, he walks over to me and says, ‘you know, I have something to show you,’” Van Roy says. Ben Moula showed him a beautifully preserved appendage with “very delicate filter-feeding morphology; it had all these fine spines,” Van Roy says. “It was shocking.”

Despite its large size, Aegirocassis seems to have been fairly common. He and the Moroccan fossil collector went on to find dozens of preserved specimens in the Moroccan desert, and there are still thousands of full or fragmentary fossils in the area.

Artistic representation of Laggania, a related creature from the same period. Image credits: Wired.

“They may have come together to molt, or they may have lived in a group,” he said. “It is interesting we found so many of them. It shows there was a well developed, rich plankton system in place 480 million years ago.”

But that doesn’t mean that there were no more surprises. The biggest one came in the form of flaps. Researchers had no idea that any anomalocaridids (the group to which Aegirocassis belong) had flaps.

“They were believed to lack limbs on the body.”

It might seem like a small matter, but the implications are actually huge: this is the missing link that explains how some crustaceans — like shrimp and lobsters — ended up with limbs that have two branches. These limbs are crucial to them, being involved in everything from gas exchange, to swimming, walking and grasping, and transferring sperm.

Biramous limbs, Zhang, X.-l., et al. (2007)

To make things even more interesting, it seems that despite being an arthropod, it actually had a surprisingly soft body.

“These extraordinary fossils are soft-bodied, which are typically very rare,” said John Paterson, an associate professor at the University of New England in Armidale, Australia, who was not involved in the study. “They require rapid burial and low oxygen conditions in order to be preserved in such exquisite detail.”

But for its impressive appearance and surprising developments, Aegirocassis was actually not a predator – he fed off of plankton.

“Given the huge size of Aegirocassis and its very alien appearance, I assume most people would probably be terrified if they’d encounter it while swimming,” said Van Roy. However, contrary to almost all other anomalocaridids which were active predators, our animal would have been a very peaceful guy.”

Journal Reference: Peter Van Roy, Allison C. Daley & Derek E. G. Briggs. Anomalocaridid trunk limb homology revealed by a giant filter-feeder with paired flaps. doi:10.1038/nature14256

Older diabetics face high over-treatment risk

The “one size fits all” approach to diabetics treatment may cause significant problems for older patients also suffering from other conditions. Attempting to aggressively control blood sugar with insulin and sulfonylurea drugs could lead to over-treatment and hypoglycemia (low blood sugar), Yale researchers report.

Diabetes overtreatment may threaten the health and lives of older patients. Image via Health Works.

The study, which was published in JAMA Internal Medicine, found that many older patients received the same treatment as their younger counterparts, despite having other health conditions to struggle with. In patients with diabetes aged 65 and older this raises major problems – potentially even life threatening ones.

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“We treat diabetes to prevent complications of the disease by lowering blood sugar levels, but the problem with aggressively lowering blood sugars in older people — to a hemoglobin A1c below 7% — is that it is uncertain whether this approach provides a benefit, and it could, in fact, cause greater harm,” said lead author Dr. Kasia Lipska, assistant professor of internal medicine at Yale School of Medicine. “Our study suggests that we have a one-size-fits-all approach despite questionable benefits and known risks. We have been potentially over-treating a substantial proportion of the population.”

This study asks some very valid questions and shows that even though managing diabetes is very important, we need to find a way to tailor treatments for individual patients and needs.

For this study, patients were divided into three groups depending on their relative health – poor, intermediate and good. Blood sugar was considered controlled if it fell below 7%. About 62% of the patients had blood sugar levels less than 7%. Out of them, 55% were treated with either insulin or sulfonylureas medications.

“We should use an individualized therapy approach when treating older diabetes patients,” said Lipska. “Older patients who are relatively healthy may benefit if they are treated in a similar way to younger diabetes patients, but this approach might not work in older patients who often have other health issues.”

Diabetes is a term denoting a group of metabolic diseases in which there are high blood sugar levels over a prolonged period. As at 2013, 382 million people have diabetes worldwide, with type 2 diabetes making for 90% of all cases.

Journal Reference: Kasia J. Lipska, Joseph S. Ross, Yinghui Miao, Nilay D. Shah, Sei J. Lee, Michael A. Steinman. Potential Overtreatment of Diabetes Mellitus in Older Adults With Tight Glycemic Control. doi:10.1001/jamainternmed.2014.7345

Adding water to solids can actually make them stronger, providing engineers with exciting new material composites

Some findings are just counterintuitive. I mean, you’d think that adding water to materials would always make them softer, right ? Well according to Yale researchers, that’s not necessarily the case. The team found that you could improve the strength of a composite by 30 percent by embedding droplets of water into its structure.

Scientists can make composite materials stronger by up to 30 percent by embedding water. Image credits: The Speaker.

Adding pockets of water to solids can actually make them stronger, offering new perspective in engineering, especially in plastic engineering (the technique doesn’t work with metals, ceramics or other structural materials). Engineers will also be able to add other properties (such as electromagnetism) to materials by embedding droplets of liquid. By understanding the interaction between water and other materials, researchers can also develop other, more advanced materials in the future.

“This is a great example of how different types of physics emerge at different scales,” Dr. Eric Dufresne, associate professor of mechanical engineering and materials science at Yale and principle investigator of the study, told The Speaker. “Shrinking the scale of an object can really change how it behaves.”

 Usually, embedding liquids (especially water) into the structure of another material makes the entire structure weaker, not stronger. However, as this research showed, surface tension could sometimes turn things around. Surface tension is the tension of the surface film of a liquid caused by the attraction of the particles in the surface layer by the bulk of the liquid, which tends to minimize surface area.a contractive tendency of the surface of a liquid that allows it to resist an external force.
“Surface tension is a force that tries to reduce the surface area of a material,” Dufresne said. “It is familiar in fluids–it’s the force that pulls water into a sponge, makes wet hair clump together and lets insects walk on water. Solids have surface tension too, but usually the ‘elastic force’ of the solid is so strong that surface tension doesn’t have much of an effect. The ‘elastic force’ of a solid is what makes a solid spring back to its original shape after you stop pushing on it.”
Duresfne called this technology “a new knob to turn” for engineers, who can now have more control over the properties they choose to include in their materials – these properties can be mechanical, electrical and even optical.
“As the solid gets stiffer, the liquid droplets need to be smaller in order to have this stiffening or cloaking effect. By embedding the solid with droplets of different materials, one can give it new electrical, optical or mechanical properties. On the simple scale, they could lower the cost be replacing expensive polymers with simple liquids. More excitingly, embedded droplets could provide an electromagnetic handle to actuate structures.”

Journal Reference: Robert W. Style, Rostislav Boltyanskiy, Benjamin Allen, Katharine E. Jensen, Henry P. Foote, John S. Wettlaufer, and Eric R. Dufresne. Stiffening solids with liquid inclusions.

Memory deficits of the elderly may be reversed

A team of researchers from Yale University have shown at a cellular basis why we tend to be more forgetful as we age, and claim that the condition may be reversed.

There’s no secret to the fact that an elderly person has a much weaker memory than the one he did at 20 years of age, but the whole process which leads to this degradation is still far from being entirely known. The researchers behind the study, recently published in the journal Nature, believe neural networks in the brains of the middle-aged and elderly have weaker connections and fire less robustly than in youthful ones.

“Age-related cognitive deficits can have a serious impact on our lives in the Information Age, as people often need higher cognitive functions to meet even basic needs, such as paying bills or accessing medical care,” says Amy Arnsten, professor of neurobiology and psychology at Yale University. “These abilities are critical for maintaining demanding careers and being able to live independently as we grow older.”

Experimenting, they looked for age-related changes in the activity of neurons in the prefrontal cortex (PFC), the area of the brain that is responsible for higher cognitive and executive functions, of variously aged animals. The PFC network of neurons is one of the brain’s most active regions when a person isn’t asleep, firing up signals constantly – this is where all the “working memory” magic is.

A neat working memory is essential for complex tasks such as reasoning, comprehension and learning. It also controls short-memory, allowing you to remember simple things like where your parked the car or put your keys, while being constantly updated and refreshed.

Arnsten and colleagues analyzed the PFC signals in young, medium-aged and old animals. They observed that young animals could maintain a higher rate of signal shooting in the working memory than those much older. Scientists looking for a reason for this, believe the PFC of older animals accumulate excessive levels of a signaling molecule called cAMP, which can open ion channels and weaken prefrontal neuronal firing.

By using agents that inhibit the generation of cAMP in the brain, they were able to to restore more youthful firing patterns in the aged neurons, albeit not exactly like those found in a young specimen – the improvements were dramatic, however. One of such agents employed was guanfacine, a neural enhancer already prescribed to children with PFC deficiencies and for hypertension treatment.

A clinical trial will shortly commence headed by Yale School of Medicine to see what kind of improvements guanfacine might have for the working memory in human subjects. Scientists doubt however that the substance might be used for treatments against Alzheimer or other forms of dementia.