Scientists have used a powerful X-ray laser to heat water from room temperature to 100,000 degrees Celsius in less than a tenth of a picosecond (millionth of a millionth of a second). The experimental set-up, that can be seen as the world's fastest water heater, produced an exotic state of water, from which researchers hope to learn more about the peculiar characteristics of Earth's most important liquid. The observations also have practical use for the probing biological and many other samples with X-ray lasers. The team of Carl Caleman from the Center for Free-Electron Laser Science (CFEL) at DESY and Uppsala University (Sweden) reports its findings in the journal Proceedings of the National Academy of Sciences (PNAS).
The researchers used the X-ray free-electron laser Linac Coherent Light Source LCLS at the SLAC National Accelerator Laboratory in the U.S. to shoot extremely intense and ultra-short flashes of X-rays at a jet of water. "It is not the usual way to boil your water," said Caleman. "Normally, when you heat water, the molecules will just be shaken stronger and stronger." On the molecular level, heat is motion -- the hotter, the faster the motion of the molecules. This can be achieved, for example, via heat transfer from a stove, or more directly with microwaves that make the water molecules swing back and forth ever faster in step with the electromagnetic field.
"Our heating is fundamentally different," explained Caleman. "The energetic X-rays punch electrons out of the water molecules, thereby destroying the balance of electric charges. So, suddenly the atoms feel a strong repulsive force and start to move violently." In less than 75 femtoseconds, that's 75 millionths of a billionth of a second or 0.000 000 000 000 075 seconds, the water goes through a phase transition from liquid to plasma. A plasma is a state of matter where the electrons have been removed from the atoms, leading to a sort of electrically charged gas.
"But while the water transforms from liquid to plasma, it still remains at the density of liquid water, as the atoms didn't have time to move significantly yet," said co-author Olof Jönsson from Uppsala University. This exotic state of matter is nothing that can be found naturally on Earth. "It has similar characteristics as some plasmas in the sun and the gas giant Jupiter, but has a lower density. Meanwhile, it is hotter than Earth's core."
The scientists used their measurements to validate simulations of the process. Together, the measurements and simulations allow to study this exotic state of water in order to learn more about water's general properties. "Water really is an odd liquid, and if it weren't for its peculiar characteristics, many things on Earth wouldn't be as they are, particularly life," Jönsson emphasised. Water displays many anomalies, including its density, heat capacity and thermal conductivity. It it these anomalies that will be investigated within the future Centre for Water Science (CWS) planned at DESY, and the obtained results are of great importance for the acivities there.
Apart from its fundamental significance, the study also has immediate practical significance. X-ray lasers are often used to investigate the atomic structure of tiny samples. "It is important for any experiment involving liquids at X-ray lasers," said co-author Kenneth Beyerlein from CFEL. "In fact, any sample that you put into the X-ray beam will be destroyed in the way that we observed. If you analyse anything that is not a crystal, you have to consider this."
Read more at Science Daily
May 15, 2018
Water plumes on Jupiter's moon Europa?
Scientists re-examining data from an old mission bring new insights to the tantalizing question of whether Jupiter's moon Europa has the ingredients to support life. The data provide independent evidence that the moon's subsurface liquid water reservoir may be venting plumes of water vapor above its icy shell.
Data collected by NASA's Galileo spacecraft in 1997 were put through new and advanced computer models to untangle a mystery -- a brief, localized bend in themagnetic field -- that had gone unexplained until now. Previous ultraviolet images from NASA's Hubble Space Telescope in 2012 suggested the presence of plumes, but this new analysis used data collected much closer to the source and is considered strong, corroborating support for plumes. The findings appear in Monday's issue of the journal Nature Astronomy.
The research was led by Xianzhe Jia, a space physicist at the University of Michigan in Ann Arbor and lead author of the journal article. Jia also is co-investigator for two instruments that will travel aboard Europa Clipper, NASA's upcoming mission to explore the moon's potential habitability.
"The data were there, but we needed sophisticated modeling to make sense of the observation," Jia said.
Jia's team was inspired to dive back into the Galileo data by Melissa McGrath of the SETI Institute in Mountain View, California. A member of the Europa Clipper science team, McGrath delivered a presentation to fellow team scientists, highlighting other Hubble observations of Europa.
"One of the locations she mentioned rang a bell. Galileo actually did a flyby of that location, and it was the closest one we ever had. We realized we had to go back," Jia said. "We needed to see whether there was anything in the data that could tell us whether or not there was a plume."
At the time of the 1997 flyby, about 124 miles (200 kilometers) above Europa's surface, the Galileo team didn't suspect the spacecraft might be grazing a plume erupting from the icy moon. Now, Jia and his team believe, its path was fortuitous.
When they examined the information gathered during that flyby 21 years ago, sure enough, high-resolution magnetometer data showed something strange. Drawing on what scientists learned from exploring plumes on Saturn's moon Enceladus -- that material in plumes becomes ionized and leaves a characteristic blip in the magnetic field -- they knew what to look for. And there it was on Europa -- a brief, localized bend in the magnetic field that had never been explained.
Galileo carried a powerful Plasma Wave Spectrometer to measure plasma waves caused by charged particles in gases around Europa's atmosphere. Jia's team pulled that data as well, and it also appeared to back the theory of a plume.
But numbers alone couldn't paint the whole picture. Jia layered the magnetometry and plasma wave signatures into new 3D modeling developed by his team at the University of Michigan, which simulated the interactions of plasma with solar system bodies. The final ingredient was the data from Hubble that suggested dimensions of potential plumes.
The result that emerged, with a simulated plume, was a match to the magnetic field and plasma signatures the team pulled from the Galileo data.
"There now seem to be too many lines of evidence to dismiss plumes at Europa," said Robert Pappalardo, Europa Clipper project scientist at NASA's Jet Propulsion Laboratory in Pasadena, California. "This result makes the plumes seem to be much more real and, for me, is a tipping point. These are no longer uncertain blips on a faraway image."
The findings are good news for the Europa Clipper mission, which may launch as early as June 2022. From its orbit of Jupiter, Europa Clipper will sail close by the moon in rapid, low-altitude flybys. If plumes are indeed spewing vapor from Europa's ocean or subsurface lakes, Europa Clipper could sample the frozen liquid and dust particles. The mission team is gearing up now to look at potential orbital paths, and the new research will play into those discussions.
Read more at Science Daily
Data collected by NASA's Galileo spacecraft in 1997 were put through new and advanced computer models to untangle a mystery -- a brief, localized bend in themagnetic field -- that had gone unexplained until now. Previous ultraviolet images from NASA's Hubble Space Telescope in 2012 suggested the presence of plumes, but this new analysis used data collected much closer to the source and is considered strong, corroborating support for plumes. The findings appear in Monday's issue of the journal Nature Astronomy.
The research was led by Xianzhe Jia, a space physicist at the University of Michigan in Ann Arbor and lead author of the journal article. Jia also is co-investigator for two instruments that will travel aboard Europa Clipper, NASA's upcoming mission to explore the moon's potential habitability.
"The data were there, but we needed sophisticated modeling to make sense of the observation," Jia said.
Jia's team was inspired to dive back into the Galileo data by Melissa McGrath of the SETI Institute in Mountain View, California. A member of the Europa Clipper science team, McGrath delivered a presentation to fellow team scientists, highlighting other Hubble observations of Europa.
"One of the locations she mentioned rang a bell. Galileo actually did a flyby of that location, and it was the closest one we ever had. We realized we had to go back," Jia said. "We needed to see whether there was anything in the data that could tell us whether or not there was a plume."
At the time of the 1997 flyby, about 124 miles (200 kilometers) above Europa's surface, the Galileo team didn't suspect the spacecraft might be grazing a plume erupting from the icy moon. Now, Jia and his team believe, its path was fortuitous.
When they examined the information gathered during that flyby 21 years ago, sure enough, high-resolution magnetometer data showed something strange. Drawing on what scientists learned from exploring plumes on Saturn's moon Enceladus -- that material in plumes becomes ionized and leaves a characteristic blip in the magnetic field -- they knew what to look for. And there it was on Europa -- a brief, localized bend in the magnetic field that had never been explained.
Galileo carried a powerful Plasma Wave Spectrometer to measure plasma waves caused by charged particles in gases around Europa's atmosphere. Jia's team pulled that data as well, and it also appeared to back the theory of a plume.
But numbers alone couldn't paint the whole picture. Jia layered the magnetometry and plasma wave signatures into new 3D modeling developed by his team at the University of Michigan, which simulated the interactions of plasma with solar system bodies. The final ingredient was the data from Hubble that suggested dimensions of potential plumes.
The result that emerged, with a simulated plume, was a match to the magnetic field and plasma signatures the team pulled from the Galileo data.
"There now seem to be too many lines of evidence to dismiss plumes at Europa," said Robert Pappalardo, Europa Clipper project scientist at NASA's Jet Propulsion Laboratory in Pasadena, California. "This result makes the plumes seem to be much more real and, for me, is a tipping point. These are no longer uncertain blips on a faraway image."
The findings are good news for the Europa Clipper mission, which may launch as early as June 2022. From its orbit of Jupiter, Europa Clipper will sail close by the moon in rapid, low-altitude flybys. If plumes are indeed spewing vapor from Europa's ocean or subsurface lakes, Europa Clipper could sample the frozen liquid and dust particles. The mission team is gearing up now to look at potential orbital paths, and the new research will play into those discussions.
Read more at Science Daily
Where hominid brains are concerned, size doesn't matter
The recently-discovered species Homo naledi may have had a pint-sized brain, but that brain packed a big punch. New research by Ralph Holloway and colleagues -- that include researchers from the University of the Witwatersrand, Johannesburg, South Africa -- published in the Proceedings of the National Academy of Sciences examines the imprints of the brain upon the skulls of this species, called endocasts. The research highlights the humanlike shape of naledi's tiny brain, surprising scientists who studied the fossils. These findings draw further into question the long-held belief that human evolution was an inevitable march towards bigger, more complex brains.
The discovery of Homo naledi by Professor Lee Berger of Wits University and his team at the Rising Star caves in the Cradle of Human Kind in 2013 was one of the largest hominin discoveries ever made and hailed as one of the most significant hominid discoveries of the 21st Century. Berger and Professor John Hawkes who was also part of the original Rising Star team who made the naledi discovery, as well as Professor Heather Garvin from Des Moines University in the US, are associated with the Evolutionary Studies Institute (ESI), based at Wits University. They are all co-authors of the current study.
In 2017, geologists demonstrated that this species existed in southern Africa between 236,000 and 335,000 years ago -- potentially the same time that modern humans first emerged in Africa. This is a puzzle to scientists, who long held that there was only one species in Africa at this late time period -- Homo sapiens. How did this species exist alongside others with brains three times its size? The new study suggests that naledi's behavior may have reflected the shape and structure of the brain more than its size.
The researchers pieced together traces of Homo naledi's brain shape from an extraordinary collection of skull fragments and partial crania, from at least five adult individuals. One of these bore a very clear imprint of the convolutions on the surface of the brain's left frontal lobe. "This is the skull I've been waiting for my whole career," said lead author Ralph Holloway, of Columbia University.
The anatomy of naledi's frontal lobe was similar to humans, and very different from great apes. Naledi wasn't alone. Other members of our genus, from Homo erectus to Homo habilis and the small-brained "hobbits," Homo floresiensis, also share features of the frontal lobe with living humans. But earlier human relatives, like Australopithecus africanus, had a much more apelike shape in this part of the brain, suggesting that functional changes in this brain region emerged with Homo. "It's too soon to speculate about language or communication in Homo naledi," said coauthor Shawn Hurst, "but today human language relies upon this brain region."
The back of the brain also showed humanlike changes in naledi compared to more primitive hominins like Australopithecus. Human brains are usually asymmetrical, with the left brain displaced forward relative to the right. The team found signs of this asymmetry in one of the most complete naledi skull fragments. They also found hints that the visual area of the brain, in the back of the cortex, was relatively smaller in naledi than in chimpanzees -- another humanlike trait.
The small brains of Homo naledi raise new questions about the evolution of human brain size. Big brains were costly to human ancestors, and some species may have paid the costs with richer diets, hunting and gathering, and longer childhoods. But that scenario doesn't seem to work well for Homo naledi, which had hands well-suited for toolmaking, long legs, humanlike feet, and teeth suggesting a high-quality diet. According to study coauthor John Hawks, "Naledi's brain seems like one you might predict for Homo habilis, two million years ago. But habilis didn't have such a tiny brain -- naledi did."
Read more at Science Daily
The discovery of Homo naledi by Professor Lee Berger of Wits University and his team at the Rising Star caves in the Cradle of Human Kind in 2013 was one of the largest hominin discoveries ever made and hailed as one of the most significant hominid discoveries of the 21st Century. Berger and Professor John Hawkes who was also part of the original Rising Star team who made the naledi discovery, as well as Professor Heather Garvin from Des Moines University in the US, are associated with the Evolutionary Studies Institute (ESI), based at Wits University. They are all co-authors of the current study.
In 2017, geologists demonstrated that this species existed in southern Africa between 236,000 and 335,000 years ago -- potentially the same time that modern humans first emerged in Africa. This is a puzzle to scientists, who long held that there was only one species in Africa at this late time period -- Homo sapiens. How did this species exist alongside others with brains three times its size? The new study suggests that naledi's behavior may have reflected the shape and structure of the brain more than its size.
The researchers pieced together traces of Homo naledi's brain shape from an extraordinary collection of skull fragments and partial crania, from at least five adult individuals. One of these bore a very clear imprint of the convolutions on the surface of the brain's left frontal lobe. "This is the skull I've been waiting for my whole career," said lead author Ralph Holloway, of Columbia University.
The anatomy of naledi's frontal lobe was similar to humans, and very different from great apes. Naledi wasn't alone. Other members of our genus, from Homo erectus to Homo habilis and the small-brained "hobbits," Homo floresiensis, also share features of the frontal lobe with living humans. But earlier human relatives, like Australopithecus africanus, had a much more apelike shape in this part of the brain, suggesting that functional changes in this brain region emerged with Homo. "It's too soon to speculate about language or communication in Homo naledi," said coauthor Shawn Hurst, "but today human language relies upon this brain region."
The back of the brain also showed humanlike changes in naledi compared to more primitive hominins like Australopithecus. Human brains are usually asymmetrical, with the left brain displaced forward relative to the right. The team found signs of this asymmetry in one of the most complete naledi skull fragments. They also found hints that the visual area of the brain, in the back of the cortex, was relatively smaller in naledi than in chimpanzees -- another humanlike trait.
The small brains of Homo naledi raise new questions about the evolution of human brain size. Big brains were costly to human ancestors, and some species may have paid the costs with richer diets, hunting and gathering, and longer childhoods. But that scenario doesn't seem to work well for Homo naledi, which had hands well-suited for toolmaking, long legs, humanlike feet, and teeth suggesting a high-quality diet. According to study coauthor John Hawks, "Naledi's brain seems like one you might predict for Homo habilis, two million years ago. But habilis didn't have such a tiny brain -- naledi did."
Read more at Science Daily
Biologists 'transfer' a memory through RNA injection
UCLA biologists report they have transferred a memory from one marine snail to another, creating an artificial memory, by injecting RNA from one to another. This research could lead to new ways to lessen the trauma of painful memories with RNA and to restore lost memories.
"I think in the not-too-distant future, we could potentially use RNA to ameliorate the effects of Alzheimer's disease or post-traumatic stress disorder," said David Glanzman, senior author of the study and a UCLA professor of integrative biology and physiology and of neurobiology. The team's research is published May 14 in eNeuro, the online journal of the Society for Neuroscience.
RNA, or ribonucleic acid, has been widely known as a cellular messenger that makes proteins and carries out DNA's instructions to other parts of the cell. It is now understood to have other important functions besides protein coding, including regulation of a variety of cellular processes involved in development and disease.
The researchers gave mild electric shocks to the tails of a species of marine snail called Aplysia. The snails received five tail shocks, one every 20 minutes, and then five more 24 hours later. The shocks enhance the snail's defensive withdrawal reflex, a response it displays for protection from potential harm. When the researchers subsequently tapped the snails, they found those that had been given the shocks displayed a defensive contraction that lasted an average of 50 seconds, a simple type of learning known as "sensitization." Those that had not been given the shocks contracted for only about one second.
The life scientists extracted RNA from the nervous systems of marine snails that received the tail shocks the day after the second series of shocks, and also from marine snails that did not receive any shocks. Then the RNA from the first (sensitized) group was injected into seven marine snails that had not received any shocks, and the RNA from the second group was injected into a control group of seven other snails that also had not received any shocks.
Remarkably, the scientists found that the seven that received the RNA from snails that were given the shocks behaved as if they themselves had received the tail shocks: They displayed a defensive contraction that lasted an average of about 40 seconds.
"It's as though we transferred the memory," said Glanzman, who is also a member of UCLA's Brain Research Institute.
As expected, the control group of snails did not display the lengthy contraction.
Next, the researchers added RNA to Petri dishes containing neurons extracted from different snails that did not receive shocks. Some dishes had RNA from marine snails that had been given electric tail shocks, and some dishes contained RNA from snails that had not been given shocks. Some of the dishes contained sensory neurons, and others contained motor neurons, which in the snail are responsible for the reflex.
When a marine snail is given electric tail shocks, its sensory neurons become more excitable. Interestingly, the researchers discovered, adding RNA from the snails that had been given shocks also produced increased excitability in sensory neurons in a Petri dish; it did not do so in motor neurons. Adding RNA from a marine snail that was not given the tail shocks did not produce this increased excitability in sensory neurons.
In the field of neuroscience, it has long been thought that memories are stored in synapses. (Each neuron has several thousand synapses.) Glanzman holds a different view, believing that memories are stored in the nucleus of neurons.
"If memories were stored at synapses, there is no way our experiment would have worked," said Glanzman, who added that the marine snail is an excellent model for studying the brain and memory.
Scientists know more about the cell biology of this simple form of learning in this animal than any other form of learning in any other organism, Glanzman said. The cellular and molecular processes seem to be very similar between the marine snail and humans, even though the snail has about 20,000 neurons in its central nervous system and humans are thought to have about 100 billion.
In the future, Glanzman said, it is possible that RNA can be used to awaken and restore memories that have gone dormant in the early stages of Alzheimer's disease. He and his colleagues published research in the journal eLife in 2014 indicating that lost memories can be restored.
Read more at Science Daily
May 14, 2018
How our ancestors with autistic traits led a revolution in Ice Age art
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| This is a drawing of a horse by Nadia, a gifted autistic child artist (left) and by a typically developing child of the same age (right). |
Around 30,000 years ago realistic art suddenly flourished in Europe. Extremely accurate depictions of bears, bison, horses and lions decorate the walls of Ice Age archaeological sites such as Chauvet Cave in southern France.
Why our ice age ancestors created exceptionally realistic art rather than the very simple or stylised art of earlier modern humans has long perplexed researchers.
Many have argued that psychotropic drugs were behind the detailed illustrations. The popular idea that drugs might make people better at art led to a number of ethically-dubious studies in the 60s where participants were given art materials and LSD.
The authors of the new study discount that theory, arguing instead that individuals with "detail focus," a trait linked to autism, kicked off an artistic movement that led to the proliferation of realistic cave drawings across Europe.
Lead author of the paper, Dr Penny Spikins from the Department of Archaeology at the University of York, said: "Detail focus is what determines whether you can draw realistically; you need it in order to be a talented realistic artist. This trait is found very commonly in people with autism and rarely occurs in people without it.
"We looked at the evidence from studies attempting to identify a link between artistic talent and drug use, and found that drugs can only serve to dis-inhibit individuals with a pre-existing ability. The idea that people with a high degree of detail focus, many of which may have had autism, set a trend for extreme realism in ice age art is a more convincing explanation."
The research adds to a growing body of evidence that people with autistic traits played an important role in human evolution.
Dr Spikins added: "Individuals with this trait -- both those who would be diagnosed with autism in the modern day and those that wouldn't -- likely played an important part in human evolution and survival as we colonised Europe.
Read more at Science Daily
Snorers suffer from nerve and muscle damage in the palate
People who snore may have extensive tissue damage in the nerves and muscles of the soft palate. This can in turn create problems with swallowing and contribute to development of sleep apnea. Treatment strategies aimed at early intervention to stop snoring might have beneficial effects in healing or preventing development of sleep apnea. These findings are explained in a new dissertation at Umeå University, Sweden.
The reason why some develop sleep apnea is still unclear. Factors that are considered important are obesity, a small throat, neurological diseases and hormonal disorders. But even those without that background can suffer. The thesis shows that tissue damage in the soft palate also is an important factor that contributes to the development of sleep apnea and disturbances in swallowing function.
"The nerve and muscles injuries seem to contribute to the collapse of the upper airway during sleep. Most likely, the damage results from the recurrent snoring vibrations the tissues are exposed to, says Farhan Shah," PhD student at the Department of Integrative Medical Biology at Umeå University.
In his dissertation, Farhan Shah reports a study where his research team has examined eight patients who have been snoring for many years and 14 patients with snoring and sleep apnea. These have been compared to a control group of 18 non-snoring people. The subjects in the study were examined with overnight sleep registrations to detect sleep apnea. Disorders of the swallowing function were investigated with a video radiographic technique.
Tissue samples from the participants' soft palate were analyzed to detect muscle and nerve lesions. The results showed that snorers and sleep apnea patients had extensive damage in both nerves and muscles. The damage was related to the degree of swallowing disorders and the severity of sleep apnea.
The nerves in the soft palate of snorers and sleep apnea patients showed fewer nerve fibers and supporting cells that help the nerve fibers survive and regenerate. The nerves also had increased connective tissue. In muscle analysis, one could see that a large number of muscle fibers in the soft palate showed changes reflecting loss of innervation due to nerve damage.
It was also possible to see changes in the protein structures in the muscle fibers' cell membrane and cell skeleton of snorers and sleep apnea patients. Such changes give muscle weakness and have been previously found only in genetic muscle diseases.
"Continued research is needed to see if treatment that prevents damage to nerves and muscles could cure or at least prevent further deterioration in snores and sleep apnea patients. It would be a big win because sleep apnea is a major public illness," says Farhan Shah.
More than 400,000 Swedes suffer from sleep apnea. The condition is characterized by snoring and recurrent respiratory arrest during sleep. It creates a stress for the body and a proven risk increases for high blood pressure, cardiovascular diseases and premature death.
Read more at Science Daily
The reason why some develop sleep apnea is still unclear. Factors that are considered important are obesity, a small throat, neurological diseases and hormonal disorders. But even those without that background can suffer. The thesis shows that tissue damage in the soft palate also is an important factor that contributes to the development of sleep apnea and disturbances in swallowing function.
"The nerve and muscles injuries seem to contribute to the collapse of the upper airway during sleep. Most likely, the damage results from the recurrent snoring vibrations the tissues are exposed to, says Farhan Shah," PhD student at the Department of Integrative Medical Biology at Umeå University.
In his dissertation, Farhan Shah reports a study where his research team has examined eight patients who have been snoring for many years and 14 patients with snoring and sleep apnea. These have been compared to a control group of 18 non-snoring people. The subjects in the study were examined with overnight sleep registrations to detect sleep apnea. Disorders of the swallowing function were investigated with a video radiographic technique.
Tissue samples from the participants' soft palate were analyzed to detect muscle and nerve lesions. The results showed that snorers and sleep apnea patients had extensive damage in both nerves and muscles. The damage was related to the degree of swallowing disorders and the severity of sleep apnea.
The nerves in the soft palate of snorers and sleep apnea patients showed fewer nerve fibers and supporting cells that help the nerve fibers survive and regenerate. The nerves also had increased connective tissue. In muscle analysis, one could see that a large number of muscle fibers in the soft palate showed changes reflecting loss of innervation due to nerve damage.
It was also possible to see changes in the protein structures in the muscle fibers' cell membrane and cell skeleton of snorers and sleep apnea patients. Such changes give muscle weakness and have been previously found only in genetic muscle diseases.
"Continued research is needed to see if treatment that prevents damage to nerves and muscles could cure or at least prevent further deterioration in snores and sleep apnea patients. It would be a big win because sleep apnea is a major public illness," says Farhan Shah.
More than 400,000 Swedes suffer from sleep apnea. The condition is characterized by snoring and recurrent respiratory arrest during sleep. It creates a stress for the body and a proven risk increases for high blood pressure, cardiovascular diseases and premature death.
Read more at Science Daily
Restoring epigenetic balance reinstates memory in flies with Alzheimer's disease symptoms
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| "When people age, they have a loss of memory but it's not because there are mutations in their genes," Elefant said. "It's the way they're packaged. They're distorted. And we're seeing non-invasive ways we might be able to prevent that early on." |
Early in the progression of Alzheimer's disease, cognitive impairment (such as difficulties with learning and memory) may be tied to the presence of elevated levels of the HDAC2 enzyme. HDAC2 helps control how genes linked to learning and memory are expressed. It appears that when HDAC2 overwhelms the enzyme it is paired with, which is called Tip60 HAT, it represses genes and leads to problems with neuroplasticity -- the brain's ability to adapt to new stimuli or recall reactions to stimuli it already encountered.
But a research team led by Priyalakshmi Panikker, a PhD student, and Felice Elefant, PhD, an associate professor, both in Drexel's College of Arts and Sciences, performed tests in flies and found that if they added extra Tip60 HAT in the brain of flies that displayed symptoms close to Alzheimer's disease, the balance between the enzymes could be successfully restored. When that balance came back, behaviors the team had taught the flies were able to be learned again and remembered.
"Our findings strongly support the concept of exploring the efficacy of specific Tip60 HAT activators, as well as identifying and manipulating additionally misregulated Tip60 target genes," Elefant said.
Elefant, Panikker and their team -- whose findings were published in the Journal of Neuroscience - looked at how Alzheimer's disease affected flies early in their development, during their larval stages, to catch what might happen in Alzheimer's well before the tell-tale symptoms arise.
"Many researchers that study Alzheimer's disease utilize human post-mortem samples, and thus, they are not looking at what is happening during the early progression of neurodegeneration, including whether we can correct what is happening during these early stages ," Elefant said.
For the study, flies were taught to associate a certain odor with sucrose -- table sugar, which flies eat and is a positive reinforcement. After being exposed to the scent paired with sugar, the flies learned to move towards the scent even without the sugar present.
Flies that modeled Alzheimer's disease showed no difference in their reaction to the smell they had earlier been condition to. This showed that their ability to learn and remember this association was negatively affected.
But once Tip60 HAT was introduced in the brain to correct the identified Tip60 HAT/HDAC2 imbalance, these flies showed a reaction time comparable to the ones without the Alzheimer's type of condition. This indicated that they recovered their ability to learn and remember after the epigenetic balance was reintroduced.
Moreover, when researchers identified a collection of genes related to brain function that had been repressed in the flies -- due to elevated HDAC2 -- an introduction of increased Tip60 HAT levels in the brain restored regular function in 9 of the 11 genes tested.
The results Panikker and Elefant found were encouraging. More testing is needed, but Elefant's goal is to find new avenues for gene therapy.
Read more at Science Daily
Forensics: New tool predicts eye, hair and skin color from a DNA sample of an unidentified individual
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| An international team, led by scientists from the School of Science at IUPUI and Erasmus MC University Medical Center Rotterdam, has developed a novel tool to accurately predict eye, hair and skin color from human biological material. The innovative high-probability and high-accuracy complete pigmentation profile webtool is available online without charge. |
The tool is designed to be used when standard forensic DNA profiling is not helpful because no reference DNA exists against which to compare the evidence sample.
The HIrisPlex-S DNA test system is capable of simultaneously predicting eye, hair and skin color phenotypes from DNA. Users, such as law enforcement officials or anthropologists, can enter relevant data using a laboratory DNA analysis tool, and the webtool will predict the pigment profile of the DNA donor.
"We have previously provided law enforcement and anthropologists with DNA tools for eye color and for combined eye and hair color, but skin color has been more difficult," said forensic geneticist Susan Walsh from IUPUI, who co-directed the study. "Importantly, we are directly predicting actual skin color divided into five subtypes -- very pale, pale, intermediate, dark and dark to black -- using DNA markers from the genes that determine an individual's skin coloration. This is not the same as identifying genetic ancestry. You might say it's more similar to specifying a paint color in a hardware store rather than denoting race or ethnicity.
"If anyone asks an eyewitness what they saw, the majority of time they mention hair color and skin color. What we are doing is using genetics to take an objective look at what they saw," Walsh said.
The innovative high-probability and high-accuracy complete pigmentation profile webtool is available online without charge.
The study, "HIrisPlex-S System for Eye, Hair and Skin Colour Prediction from DNA: Introduction and Forensic Developmental Validation," is published in the peer-reviewed journal Forensic Science International: Genetics.
Read more at Science Daily
May 13, 2018
Alcohol and tobacco are by far the biggest threat to human welfare of all addictive drugs
A new review published online today in the journal Addiction has compiled the best, most up-to-date source of information on alcohol, tobacco, and illicit drug use and the burden of death and disease. It shows that in 2015 alcohol and tobacco use between them cost the human population more than a quarter of a billion disability-adjusted life years, with illicit drugs costing a further tens of millions.
The largest health burden from substance use was attributable to tobacco smoking and the smallest was attributable to illicit drugs. Global estimates suggest that nearly one in seven adults (15.2%) smoke tobacco and one in five adults report at least one occasion of heavy alcohol use in the past month.
Compared with the rest of the world, Central, Eastern, and Western Europe recorded consistently higher alcohol consumption per capita (11.61, 11.98 and 11.09 litres, respectively) and a higher percentage of heavy consumption amongst drinkers (50.5%, 48.2%, and 40.2%, respectively). The same European regions also recorded the highest prevalence of tobacco smoking (Eastern Europe 24.2%, Central Europe 23.7%, and Western Europe 20.9%).
In contrast, use of illicit drugs was far less common. Fewer than one in twenty people were estimated to use cannabis in the past year, and much lower estimates were observed for amphetamines, opioids and cocaine. Hotspots included the US, Canada, and Australasia. The US and Canada had one of the highest rates of cannabis, opioid, and cocaine dependence (748.7 [694.8, 812.3], 650.0 [574.5, 727.3], and 301.2 [269.3, 333.7] per 100,000 people, respectively). Australasia (Australia and New Zealand) had the highest prevalence of amphetamine dependence (491.5 per 100,000 people [441.4, 545.5]), as well as high rates of cannabis, opioid and cocaine use dependence (693.7 [648.1, 744.4], 509.9 [453.7, 577.8], and 160.5 [136.4, 187.1] per 100,000 people, respectively).
Some countries and regions (e.g., Africa, Caribbean and Latin America, Asia regions) have little or no data on substance use and associated health burden. These are typically low or middle income countries that frequently have punitive drug policies, and may experience serious political and social unrest. These countries need enhanced monitoring because they are at risk of rapid escalation in substance use and related health burden.
The report, 'Global Statistics on Alcohol, Tobacco, and Illicit Drug Use: 2017 Status Report', uses data mainly obtained from the World Health Organization, United Nations Office on Drugs and Crime, and Institute for Health Metrics and Evaluation. The authors note that there are important limitations to the data, especially for illicit drugs, but believe that putting all this information in one place will make it easier for governments and international agencies to develop policies to combat substance use.
From Science Daily
The largest health burden from substance use was attributable to tobacco smoking and the smallest was attributable to illicit drugs. Global estimates suggest that nearly one in seven adults (15.2%) smoke tobacco and one in five adults report at least one occasion of heavy alcohol use in the past month.
Compared with the rest of the world, Central, Eastern, and Western Europe recorded consistently higher alcohol consumption per capita (11.61, 11.98 and 11.09 litres, respectively) and a higher percentage of heavy consumption amongst drinkers (50.5%, 48.2%, and 40.2%, respectively). The same European regions also recorded the highest prevalence of tobacco smoking (Eastern Europe 24.2%, Central Europe 23.7%, and Western Europe 20.9%).
In contrast, use of illicit drugs was far less common. Fewer than one in twenty people were estimated to use cannabis in the past year, and much lower estimates were observed for amphetamines, opioids and cocaine. Hotspots included the US, Canada, and Australasia. The US and Canada had one of the highest rates of cannabis, opioid, and cocaine dependence (748.7 [694.8, 812.3], 650.0 [574.5, 727.3], and 301.2 [269.3, 333.7] per 100,000 people, respectively). Australasia (Australia and New Zealand) had the highest prevalence of amphetamine dependence (491.5 per 100,000 people [441.4, 545.5]), as well as high rates of cannabis, opioid and cocaine use dependence (693.7 [648.1, 744.4], 509.9 [453.7, 577.8], and 160.5 [136.4, 187.1] per 100,000 people, respectively).
Some countries and regions (e.g., Africa, Caribbean and Latin America, Asia regions) have little or no data on substance use and associated health burden. These are typically low or middle income countries that frequently have punitive drug policies, and may experience serious political and social unrest. These countries need enhanced monitoring because they are at risk of rapid escalation in substance use and related health burden.
The report, 'Global Statistics on Alcohol, Tobacco, and Illicit Drug Use: 2017 Status Report', uses data mainly obtained from the World Health Organization, United Nations Office on Drugs and Crime, and Institute for Health Metrics and Evaluation. The authors note that there are important limitations to the data, especially for illicit drugs, but believe that putting all this information in one place will make it easier for governments and international agencies to develop policies to combat substance use.
From Science Daily
The evolution of conflict resolution
Recently published in the Journal of the Royal Society Interface, Assistant Professor Christoph Riedl's latest research examines a model that might explain how humans resolve conflict, and what these actions say about biological and social behavior, both now and into the future.
Dynamic networks allow individuals to resolve conflicts by managing their network connections rather than changing their strategy. This is a common phenomenon among humans who can make deliberate choices regarding who they want to interact with.
"Let's use an example: You're at a friend's house and you're both eating appetizers," explains Riedl. "When only one appetizer is left, how do you decide who gets it? If you both really want it, then you are involved in a potential conflict, and there are several socially accepted ways of solving the issue. But which norm should you settle on, and why?"
With these social constructs in mind, Riedl's research started by looking at traditional games of conflict, such as "the game of chicken," and applying computer simulations to examine how disagreements get resolved efficiently to encourage cooperation.
These simulations showed Riedl and his team -- Tufts University Associate Professor of Philosophy Rory Smead, Northeastern University Associate Professor of Philosophy Patrick Forber, and Network Science Institute PhD student Michael Foley -- that one social solution far outweighs the other, instead of both behaviors being exhibited equally.
"Host-guest norms or 'paradoxical behavior' account for the vast majority of our simulated final state solutions -- in other words, the host gives the guest the last appetizer," says Riedl. "The opposite solution where the host takes the appetizer for himself, called ownership norms or 'bourgeois behavior,' is quite rare."
"This is especially interesting in the context of human biological behavior because in the animal kingdom, territoriality or ownership norms are ubiquitous."
And so, how and why did the host-guest norm evolve into the more socially accepted conflict resolution in human beings, and how might that affect the future? The research suggests that this is due to the dynamic nature of the social network which allows actors to choose their interaction partners. This entails that insofar ownership and territoriality are probably widespread due to the intrinsic importance of holding resources or the value of owning a territory rather than as a convention for avoiding conflict. Riedl and his fellow researchers are hard at work to unveil additional details about the evolutionary dynamics of when or where certain conventions may arise.
From Science Daily
Dynamic networks allow individuals to resolve conflicts by managing their network connections rather than changing their strategy. This is a common phenomenon among humans who can make deliberate choices regarding who they want to interact with.
"Let's use an example: You're at a friend's house and you're both eating appetizers," explains Riedl. "When only one appetizer is left, how do you decide who gets it? If you both really want it, then you are involved in a potential conflict, and there are several socially accepted ways of solving the issue. But which norm should you settle on, and why?"
With these social constructs in mind, Riedl's research started by looking at traditional games of conflict, such as "the game of chicken," and applying computer simulations to examine how disagreements get resolved efficiently to encourage cooperation.
These simulations showed Riedl and his team -- Tufts University Associate Professor of Philosophy Rory Smead, Northeastern University Associate Professor of Philosophy Patrick Forber, and Network Science Institute PhD student Michael Foley -- that one social solution far outweighs the other, instead of both behaviors being exhibited equally.
"Host-guest norms or 'paradoxical behavior' account for the vast majority of our simulated final state solutions -- in other words, the host gives the guest the last appetizer," says Riedl. "The opposite solution where the host takes the appetizer for himself, called ownership norms or 'bourgeois behavior,' is quite rare."
"This is especially interesting in the context of human biological behavior because in the animal kingdom, territoriality or ownership norms are ubiquitous."
And so, how and why did the host-guest norm evolve into the more socially accepted conflict resolution in human beings, and how might that affect the future? The research suggests that this is due to the dynamic nature of the social network which allows actors to choose their interaction partners. This entails that insofar ownership and territoriality are probably widespread due to the intrinsic importance of holding resources or the value of owning a territory rather than as a convention for avoiding conflict. Riedl and his fellow researchers are hard at work to unveil additional details about the evolutionary dynamics of when or where certain conventions may arise.
From Science Daily
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