A Queen's University Belfast scientist has led an international team to the ground-breaking discovery of why the Sun's magnetic waves strengthen and grow as they emerge from its surface, which could help to solve the mystery of how the corona of the Sun maintains its multi-million degree temperatures.
For more than 60 years observations of the Sun have shown that as the magnetic waves leave the interior of the Sun they grow in strength but until now there has been no solid observational evidence as to why this was the case.
The corona's high temperatures have also always been a mystery. Usually the closer we are to a heat source, the warmer we feel. However, this is the opposite of what seems to happen on the Sun -- its outer layers are warmer than the heat source at its surface.
Scientists have accepted for a long time that magnetic waves channel energy from the Sun's vast interior energy reservoir, which is powered by nuclear fusion, up into the outer regions of its atmosphere. Therefore, understanding how the wave motion is generated and spread throughout the Sun is of huge importance to researchers.
The team, which was led by Queen's, included 13 scientists, spanning five countries and 11 research institutes including University of Exeter; Northumbria University; the European Space Agency; Instituto de Astrofísica de Canarias, Spain; University of Oslo, Norway; the Italian Space Agency and California State University Northridge, USA.
The experts formed a consortium called "Waves in the Lower Solar Atmosphere (WaLSA)" to carry out the research and used advanced high-resolution observations from the National Science Foundation's Dunn Solar Telescope, New Mexico, to study the waves.
Dr David Jess from the School of Mathematics and Physics at Queen's led the team of experts. He explains: "This new understanding of wave motion may help scientists uncover the missing piece in the puzzle of why the outer layers of the Sun are hotter than its surface, despite being further from the heat source.
"By breaking the Sun's light up into its basic colours, we were able to examine the behaviour of certain elements from the periodic table within its atmosphere, including silicon (formed close to the Sun's surface), calcium and helium (formed in the chromosphere where the wave amplification is most apparent).
"The variations in the elements allowed the speeds of the Sun's plasma to be uncovered. The timescales over which they evolve were benchmarked, which allowed the wave frequencies of the Sun to be recorded. This is similar to how a complex musical ensemble is deconstructed into basic notes and frequencies by visualising its musical score."
The team then used super computers to analyse the data through simulations. They found that the wave amplification process can be attributed to the formation of an 'acoustic resonator', where significant changes in temperature between the surface of the Sun and its outer corona create boundaries that are partially reflective and act to trap the waves, allowing them to intensify and dramatically grow in strength.
The experts also found that the thickness of the resonance cavity -the distance between the significant temperature changes -- is one of the main factors governing the characteristics of the detected wave motion.
Dr Jess comments: "The effect that we have found through the research is similar to how an acoustic guitar changes the sound it emits through the shape of its hollow body. If we think of this analogy we can see how the waves captured in the Sun can grow and change as they exit its surface and move towards the outer layers and exterior."
Read more at Science Daily
Dec 3, 2019
How does language emerge?
How the languages of the world emerged is largely a mystery. Considering that it might have taken millennia, it is intriguing to see how deaf people can create novel sign languages spontaneously. Observations have shown that when deaf strangers are brought together in a community, they come up with their own sign language in a considerably short amount of time. The most famous example of this is Nicaraguan Sign Language, which emerged in the 1980s. Interestingly, children played an important role in the development of these novel languages. However, how exactly this happened has not been documented, as Manuel Bohn describes: "We know relatively little about how social interaction becomes language. This is where our new study comes in."
In a series of studies, researchers at the Leipzig Research Centre for Early Childhood Development and the Max Planck Institute for Evolutionary Anthropology attempted to recreate exactly this process. The idea had been around for quite some time, says Gregor Kachel. But there was a problem: how to make children communicate with each other without them reverting to talking to each other? The solution came up in Skype conversations between the two researchers from Germany and their colleague Michael Tomasello in the US. In the study, children were invited to stay in two different rooms and a Skype connection was established between them. After a brief familiarization with the set-up, the researchers sneakily turned off the sound and watched as the children found new ways of communicating that go beyond spoken language.
The children's task was to describe an image with different motifs in a coordination game. With concrete things -- like a hammer or a fork -- children quickly found a solution by imitating the corresponding action (e.g. eating) in a gesture. But the researchers repeatedly challenged the children with new, more abstract pictures. For example, they introduced a white sheet of paper as a picture. The depicted "nothing" is difficult to imitate. Kachel describes how two children nevertheless mastered this task: "The sender first tried all sorts of different gestures, but her partner let her know that she did not know what was meant. Suddenly our sender pulled her T-shirt to the side and pointed to a white dot on her coloured T-shirt. The two had a real breakthrough: of course! White! Like the white paper! Later, when the roles were switched, the recipient didn't have a white spot on her T-shirt, but she nevertheless took the same approach: she pulled her T-shirt to the side and pointed to it. Immediately her partner knew what to do." Within a very short time, the two had established a sign for an abstract concept. In the course of the study, the images to be depicted became more and more complex, which was also reflected in the gestures that the children produced. In order to communicate, for example, an interaction between two animals, children invented separate gestures for actors and actions and began to combine them -- thus creating a kind of small local grammar.
How does a language emerge? Based on the present study, the following steps appear plausible: first, people create reference to actions and objects via signs that resemble things. The prerequisite for this is a common ground of experience between interaction partners. Partners also coordinate by imitating each other such that they use the same signs for the same things. The signs thus gain interpersonal and eventually conventional meaning. Over time, the relationships between the signs and things become more abstract and the meaning of the individual signs more specific. Grammatical structures are gradually introduced when there is a need to communicate more complex facts. However, the most remarkable aspect of the current studies is that these processes can be observed under controlled circumstances and within 30 minutes.
Read more at Science Daily
In a series of studies, researchers at the Leipzig Research Centre for Early Childhood Development and the Max Planck Institute for Evolutionary Anthropology attempted to recreate exactly this process. The idea had been around for quite some time, says Gregor Kachel. But there was a problem: how to make children communicate with each other without them reverting to talking to each other? The solution came up in Skype conversations between the two researchers from Germany and their colleague Michael Tomasello in the US. In the study, children were invited to stay in two different rooms and a Skype connection was established between them. After a brief familiarization with the set-up, the researchers sneakily turned off the sound and watched as the children found new ways of communicating that go beyond spoken language.
The children's task was to describe an image with different motifs in a coordination game. With concrete things -- like a hammer or a fork -- children quickly found a solution by imitating the corresponding action (e.g. eating) in a gesture. But the researchers repeatedly challenged the children with new, more abstract pictures. For example, they introduced a white sheet of paper as a picture. The depicted "nothing" is difficult to imitate. Kachel describes how two children nevertheless mastered this task: "The sender first tried all sorts of different gestures, but her partner let her know that she did not know what was meant. Suddenly our sender pulled her T-shirt to the side and pointed to a white dot on her coloured T-shirt. The two had a real breakthrough: of course! White! Like the white paper! Later, when the roles were switched, the recipient didn't have a white spot on her T-shirt, but she nevertheless took the same approach: she pulled her T-shirt to the side and pointed to it. Immediately her partner knew what to do." Within a very short time, the two had established a sign for an abstract concept. In the course of the study, the images to be depicted became more and more complex, which was also reflected in the gestures that the children produced. In order to communicate, for example, an interaction between two animals, children invented separate gestures for actors and actions and began to combine them -- thus creating a kind of small local grammar.
How does a language emerge? Based on the present study, the following steps appear plausible: first, people create reference to actions and objects via signs that resemble things. The prerequisite for this is a common ground of experience between interaction partners. Partners also coordinate by imitating each other such that they use the same signs for the same things. The signs thus gain interpersonal and eventually conventional meaning. Over time, the relationships between the signs and things become more abstract and the meaning of the individual signs more specific. Grammatical structures are gradually introduced when there is a need to communicate more complex facts. However, the most remarkable aspect of the current studies is that these processes can be observed under controlled circumstances and within 30 minutes.
Read more at Science Daily
Eating in sync with biological clock could replace problematic diabetes treatment
Type 2 diabetics inject themselves with insulin, a hormone that regulates the movement of sugar into liver, muscle and fat cells, up to four times a day. But insulin injections are linked to weight gain and the loss of control of blood sugar levels. This triggers a vicious cycle of higher insulin doses, continuous weight gain, a higher incidence of cardiovascular disease and other complications.
A new Tel Aviv University study finds that a starch-rich breakfast consumed early in the morning coupled with a small dinner could replace insulin injections and other diabetes medications for many diabetics.
"The traditional diabetic diet specifies six small meals spread throughout the day. But our research proposes shifting the starch-rich calories to the early hours of the day. This produces a glucose balance and improved glycemic control among type 2 diabetics," explains Prof. Daniela Jakubowicz of TAU's Sackler Faculty of Medicine and Wolfson Medical Center's Diabetes Unit. "We believe that through this regimen it will be possible for diabetics to significantly reduce or even stop the injections of insulin, and most of antidiabetic medications, to achieve excellent control of glucose levels."
Prof. Jakubowicz is the lead author of the study, the result of a collaboration with Prof. Julio Wainstein and Dr. Zohar Landau of Wolfson Medical Center's Diabetes Unit and Prof. Oren Froy and Dr. Shani Tsameret of the Hebrew University of Jerusalem. The research was published in Diabetes Care in December.
According to the new research, our metabolism and biological clock are optimized for eating in the morning and for fasting during the evening and night, when we are supposed to be asleep. "But the usual diet recommended for type 2 diabetes consists of several small meals evenly distributed throughout the day -- for example, three meals and three snacks daily, including a snack before going to sleep to prevent a drop in sugar levels during the night," Prof. Jakubowicz says.
"But the '6M-diet,' as this is called, has not been effective for sugar control, so diabetics require additional medication and insulin. And insulin injections lead to weight gain, which further increases blood sugar levels," Prof. Jakubowicz adds.
The researchers studied 29 type 2 diabetes participants and compared a new "3M-diet," more in alignment with our biological clock, with a control group on the traditional 6M-diet. The experimental 3M-diet comprises a meal of bread, fruits and sweets in the early hours of the morning; a substantial lunch; and a small dinner specifically lacking starches, sweets and fruits.
The group on the traditional 6M-diet did not lose weight and did not experience any improvement of sugar levels, requiring an increase in medication and insulin doses. But the group on the 3M-diet not only lost weight but also experienced substantially improved sugar levels.
"Their need for diabetic medication, especially for insulin doses, dipped substantially. Some were even able to stop using insulin altogether," adds Prof. Jakubowicz. "In addition, the 3M-diet improved the expression of biological clock genes. This suggests that the 3M-diet is not only more effective in controlling diabetes. It may also prevent many other complications such as cardiovascular disease, aging and cancer, which are all regulated by the biological clock genes."
Read more at Science Daily
A new Tel Aviv University study finds that a starch-rich breakfast consumed early in the morning coupled with a small dinner could replace insulin injections and other diabetes medications for many diabetics.
"The traditional diabetic diet specifies six small meals spread throughout the day. But our research proposes shifting the starch-rich calories to the early hours of the day. This produces a glucose balance and improved glycemic control among type 2 diabetics," explains Prof. Daniela Jakubowicz of TAU's Sackler Faculty of Medicine and Wolfson Medical Center's Diabetes Unit. "We believe that through this regimen it will be possible for diabetics to significantly reduce or even stop the injections of insulin, and most of antidiabetic medications, to achieve excellent control of glucose levels."
Prof. Jakubowicz is the lead author of the study, the result of a collaboration with Prof. Julio Wainstein and Dr. Zohar Landau of Wolfson Medical Center's Diabetes Unit and Prof. Oren Froy and Dr. Shani Tsameret of the Hebrew University of Jerusalem. The research was published in Diabetes Care in December.
According to the new research, our metabolism and biological clock are optimized for eating in the morning and for fasting during the evening and night, when we are supposed to be asleep. "But the usual diet recommended for type 2 diabetes consists of several small meals evenly distributed throughout the day -- for example, three meals and three snacks daily, including a snack before going to sleep to prevent a drop in sugar levels during the night," Prof. Jakubowicz says.
"But the '6M-diet,' as this is called, has not been effective for sugar control, so diabetics require additional medication and insulin. And insulin injections lead to weight gain, which further increases blood sugar levels," Prof. Jakubowicz adds.
The researchers studied 29 type 2 diabetes participants and compared a new "3M-diet," more in alignment with our biological clock, with a control group on the traditional 6M-diet. The experimental 3M-diet comprises a meal of bread, fruits and sweets in the early hours of the morning; a substantial lunch; and a small dinner specifically lacking starches, sweets and fruits.
The group on the traditional 6M-diet did not lose weight and did not experience any improvement of sugar levels, requiring an increase in medication and insulin doses. But the group on the 3M-diet not only lost weight but also experienced substantially improved sugar levels.
"Their need for diabetic medication, especially for insulin doses, dipped substantially. Some were even able to stop using insulin altogether," adds Prof. Jakubowicz. "In addition, the 3M-diet improved the expression of biological clock genes. This suggests that the 3M-diet is not only more effective in controlling diabetes. It may also prevent many other complications such as cardiovascular disease, aging and cancer, which are all regulated by the biological clock genes."
Read more at Science Daily
Bacterial communities 'hitchhiking' on marine plastic trash
Millions of tons of plastic trash are fouling the world's ocean, most of it tiny pieces of microplastic less than a quarter-inch in size. Even the smallest marine animals can ingest these microplastics, potentially threatening their survival.
Marine microplastics aren't floating solo, either -- they quickly pick up a thin coating of bacteria and other microbes, a biofilm known as "The Plastisphere." These biofilms can influence the microplastics' fate -- causing them to sink or float, or breaking them down into even tinier bits, for example. They can even make the plastic smell or taste like food to some marine organisms. But very little is known about what kinds of microbes are in the Plastisphere, and how they interact with one another and the plastic.
Now, using an innovative microscopy method developed at the Marine Biological Laboratory (MBL), Woods Hole, scientists have revealed the structure of the microbial communities coating microplastic samples from a variety of ocean sites. The team, led by Linda Amaral-Zettler (who coined the term "Plastisphere"), Jessica Mark Welch, and Cathleen Schlundt, reports its results this week in Molecular Ecology Resources.
The MBL team built upon an fluorescence imaging technique developed by Mark Welch and colleagues to literally see the spatial organization of microbes on the plastic samples. They did so by designing probes that fluorescently lit up and targeted major, known bacterial groups in the Plastisphere.
"We now have a toolkit that enables us to understand the spatial structure of the Plastisphere and, combined with other methods, a better future way to understand the Plastisphere's major microbial players, what they are doing, and their impact on the fate of plastic litter in the ocean," said Amaral-Zettler, a MBL Fellow from the NIOZ Royal Netherlands Institute for Sea Research and the University of Amsterdam.
The scientists saw diatoms and bacteria colonizing the microplastics, dominated in all cases by three phyla: Proteobacteria, Cyanobacteria, and Bacteriodetes. Spatially, the Plastisphere microbial communities were heterogeneously mixed, providing the first glimpse of bacterial interactions on marine microplastics.
Mark Welch and colleagues have previously applied their imaging technology to study microbial communities in the human mouth and in the digestive tract of cuttlefish and vertebrates.
Read more at Science Daily
Marine microplastics aren't floating solo, either -- they quickly pick up a thin coating of bacteria and other microbes, a biofilm known as "The Plastisphere." These biofilms can influence the microplastics' fate -- causing them to sink or float, or breaking them down into even tinier bits, for example. They can even make the plastic smell or taste like food to some marine organisms. But very little is known about what kinds of microbes are in the Plastisphere, and how they interact with one another and the plastic.
Now, using an innovative microscopy method developed at the Marine Biological Laboratory (MBL), Woods Hole, scientists have revealed the structure of the microbial communities coating microplastic samples from a variety of ocean sites. The team, led by Linda Amaral-Zettler (who coined the term "Plastisphere"), Jessica Mark Welch, and Cathleen Schlundt, reports its results this week in Molecular Ecology Resources.
The MBL team built upon an fluorescence imaging technique developed by Mark Welch and colleagues to literally see the spatial organization of microbes on the plastic samples. They did so by designing probes that fluorescently lit up and targeted major, known bacterial groups in the Plastisphere.
"We now have a toolkit that enables us to understand the spatial structure of the Plastisphere and, combined with other methods, a better future way to understand the Plastisphere's major microbial players, what they are doing, and their impact on the fate of plastic litter in the ocean," said Amaral-Zettler, a MBL Fellow from the NIOZ Royal Netherlands Institute for Sea Research and the University of Amsterdam.
The scientists saw diatoms and bacteria colonizing the microplastics, dominated in all cases by three phyla: Proteobacteria, Cyanobacteria, and Bacteriodetes. Spatially, the Plastisphere microbial communities were heterogeneously mixed, providing the first glimpse of bacterial interactions on marine microplastics.
Mark Welch and colleagues have previously applied their imaging technology to study microbial communities in the human mouth and in the digestive tract of cuttlefish and vertebrates.
Read more at Science Daily
Dec 2, 2019
Global levels of biodiversity could be lower than we think, new study warns
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| Tropical forest |
The study by PhD graduate Dr Martin Jung, Senior Lecturer in Geography Dr Pedram Rowhani and Professor of Conservation Science Jörn Scharlemann, all at the University of Sussex, shows that fewer species and fewer individuals are observed at sites that have been disturbed by an abrupt land change in past decades.
The authors warn that areas subjected to deforestation or intensification of agriculture can take at least ten years to recover, with reductions in species richness and abundance.
With current biodiversity assessments failing to take into account the impacts of past land changes, the researchers believe that the natural world could be in a far worse state than currently thought.
Lead author, Dr Martin Jung said: "These findings show that recent abrupt land changes, like deforestation or intensification through agriculture, can cause even more impactful and long-lasting damage to biodiversity than previously thought.
"Our study shows that it can take at least ten or more years for areas which have undergone recent abrupt land changes to recover to levels comparable to undisturbed sites. This only strengthens the argument to limit the impacts of land change on biodiversity with immediate haste."
The study combined global data on biodiversity from the PREDICTS database, one of the largest databases of terrestrial plants, fungi and animals across the world, with quantitative estimates of abrupt land change detected using images from NASA's Landsat satellites from 1982 to 2015.
Comparing numbers of plants, fungi and animals at 5,563 disturbed sites with those at 10,102 undisturbed sites across the world from Africa to Asia, the researchers found that biodiversity remains affected by a land change event for several years after it has occurred, due to a lag effect.
Species richness and abundance were found to be 4.2% and 2% lower, respectively, at sites where an abrupt land change had occurred.
In addition, the impacts on species were found to be greater if land changes had occurred more recently, and caused greater changes in vegetation cover. At sites that had land changes in the last five years, there were around 6.6% fewer species observed.
However, at sites where a land change had taken place 10 or more years ago, species richness and abundance were indistinguishable from sites without a past land change in the same period, indicating that biodiversity can recover after such disturbances.
Dr Jung explained: "For us, the results clearly indicate that regional and global biodiversity assessments need to consider looking back at the past in order to have more accurate results in the present.
"We've shown that remotely-sensed satellite data can assist in doing this in a robust way globally. Our framework can also be applied to habitat restoration and conservation prioritization assessments."
Read more at Science Daily
How ancient microbes created massive ore deposits, set stage for early life
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| Lake Kivu |
University of British Columbia (UBC) researchers, and collaborators from the universities of Alberta, Tübingen, Autònoma de Barcelona and the Georgia Institute of Technology, found that ancestors of modern bacteria cultured from an iron-rich lake in Democratic Republic of Congo could have been key to keeping Earth's dimly lit early climate warm, and in forming the world's largest iron ore deposits billions of years ago.
The bacteria have special chemical and physical features that in the complete absence of oxygen allow them to convert energy from sunlight into rusty iron minerals and into cellular biomass. The biomass ultimately causes the production of the potent greenhouse gas methane by other microbes.
"Using modern geomicrobiological techniques, we found that certain bacteria have surfaces which allow them to expel iron minerals, making it possible for them to export these minerals to the seafloor to make ore deposits," said Katharine Thompson, lead author of the study and PhD student in the department of microbiology and immunology.
"Separated from their rusty mineral products, these bacteria then go on to feed other microbes that make methane. That methane is what likely kept Earth's early atmosphere warm, even though the sun was much less bright than today."
This is a possible explanation to the 'faint-young-sun' paradox, originated by astronomer Carl Sagan. The paradox is that there were liquid oceans on early Earth, yet heat budgets calculated from the early Sun's luminosity and modern atmospheric chemistry imply Earth should have been entirely frozen. A frozen Earth would not have supported very much life. A methane-rich atmosphere formed in connection to large-scale iron ore deposits and life was initially proposed by University of Michigan atmospheric scientist James Walker in 1987. The new study provides strong physical evidence to support the theory and finds that microscale bacterial-mineral interactions were likely responsible.
"The fundamental knowledge we're gaining from studies using modern geomicrobiological tools and techniques is transforming our view of Earth's early history and the processes that led to a planet habitable by complex life including humans," said senior author of the paper, Sean Crowe, Canada Research Chair in Geomicrobiology and associate professor at UBC.
"This knowledge of the chemical and physical processes through which bacteria interact with their surroundings can also be used to develop and design new processes for resource recovery, novel building and construction materials, and new approaches to treating disease."
Read more at Science Daily
Why do we freeze when startled? New study in flies points to serotonin
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| Fruit fly |
These findings, published today in Current Biology, offer broad insight into the biology of the startle response, a ubiquitous, yet mysterious, phenomenon that has been observed in virtually every animal studied to date, from flies to fish to people.
"Imagine sitting in your living room with your family and -- all of a sudden -- the lights go out, or the ground begins to shake," said Richard Mann, PhD, a principal investigator at Columbia's Mortimer B. Zuckerman Mind Brain Behavior Institute and the paper's senior author. "Your response, and that of your family, will be the same: You will stop, freeze and then move to safety. With this study, we show in flies that a rapid release of the chemical serotonin in their nervous system drives that initial freeze. And because serotonin also exists in people, these findings shed light on what may be going on when we get startled as well."
In the brain, serotonin is most closely associated with regulating mood and emotion. But previous research on flies and vertebrates has shown it can also affect the speed of an animal's movement. The Columbia researchers' initial goal was to more fully understand how the chemical accomplished this.
The team first analyzed fruit fly steps using FlyWalker, an apparatus developed by Dr. Mann and Columbia physicist Szabolcs Marka, PhD, to track an insect's steps on a special type of glass. After monitoring how the flies moved, the scientists manipulated the levels of serotonin -- and another chemical called dopamine -- in the fly's ventral nerve cord (VNC), which is analogous to the vertebrate spinal cord.
Their initial results revealed that activating neurons that produce serotonin in the VNC slows flies down, while silencing those same neurons speeds flies up. Additional experiments showed that serotonin levels could impact the insects' walking speed under a wide variety of conditions, including different temperatures, when the flies were hungry, or while they walked upside down, all situations that normally affect walking speed.
"We witnessed serotonin's biggest effects when the flies experienced rapid environmental changes," said Clare Howard, PhD, the paper's first author. "In other words, when they were startled."
To further investigate, the research team devised two scenarios to elicit a fly's startle response. In the first, they turned the lights off: a total blackout for the insects. For the second, they simulated an earthquake.
To accomplish this, the scientists partnered with Tanya Tabachnik, Director of Advanced Instrumentation at Columbia's Zuckerman Institute. Tabachnik's team of machinists and engineers works with scientists to design and build customized systems for their research. For this study, they created a miniature, fly-sized arena perched atop specialized vibrating motors. Adjusting the motors' strength produced the desired earthquake effect. When the researchers exposed the flies to either the blackout or earthquake scenarios, they also manipulated the fly's ability to produce serotonin.
"We found that when a fly is startled in these scenarios, serotonin acts like an emergency brake; its release is needed for them to freeze, and that part of this response may be a result of stiffening both sides of the animal's leg joints," said Dr. Mann, who is also the Higgins Professor of Biochemistry and Molecular Biophysics (in Systems Biology) at Columbia's Vagelos College of Physicians and Surgeons. "This co-contraction could cause the brief pause in walking, after which the insect begins to move."
"We think this pause is important," added Dr. Howard, "It could allow the fly's nervous system to gather the information about this sudden change and decide how it should respond."
Interestingly, even though the fly's response in both scenarios was to cause an immediate pause, their subsequent walking speeds differed significantly.
"After being startled in the blackout scenario, the fly's gait was slow and deliberate," Dr. Howard said. "But the earthquake caused the flies to walk faster after the initial pause."
While these findings are specific to fruit flies, the ubiquity of serotonin and the startle response provides clues as to the chemical and molecular processes that occur when more complex animals, including people, get startled.
Going forward, the researchers hope to further investigate serotonin's role in movement, as well as what other factors may be at play.
Read more at Science Daily
The coldest reaction
The coldest chemical reaction in the known universe took place in what appears to be a chaotic mess of lasers. The appearance deceives: Deep within that painstakingly organized chaos, in temperatures millions of times colder than interstellar space, Kang-Kuen Ni achieved a feat of precision. Forcing two ultracold molecules to meet and react, she broke and formed the coldest bonds in the history of molecular couplings.
"Probably in the next couple of years, we are the only lab that can do this," said Ming-Guang Hu, a postdoctoral scholar in the Ni lab and first author on their paper published today in Science. Five years ago, Ni, the Morris Kahn Associate Professor of Chemistry and Chemical Biology and a pioneer of ultracold chemistry, set out to build a new apparatus that could achieve the lowest temperature chemical reactions of any currently available technology. But they couldn't be sure their intricate engineering would work.
Now, they not only performed the coldest reaction yet, they discovered their new apparatus can do something even they did not predict. In such intense cold -- 500 nanokelvin or just a few millionths of a degree above absolute zero -- their molecules slowed to such glacial speeds, Ni and her team could see something no one has been able to see before: the moment when two molecules meet to form two new molecules. In essence, they captured a chemical reaction in its most critical and elusive act.
Chemical reactions are responsible for literally everything: breathing, cooking, digesting, creating energy, pharmaceuticals, and household products like soap. So, understanding how they work at a fundamental level could help researchers design combinations the world has never seen. With an almost infinite number of new combinations possible, these new molecules could have endless applications from more efficient energy production to new materials like mold-proof walls and even better building blocks for quantum computers.
In her previous work, Ni used colder and colder temperatures to work this chemical magic: forging molecules from atoms that would otherwise never react. Cooled to such extremes, atoms and molecules slow to a quantum crawl, their lowest possible energy state. There, Ni can manipulate molecular interactions with utmost precision. But even she could only see the start of her reactions: two molecules go in, but then what? What happened in the middle and the end was a black hole only theories could try to explain.
Chemical reactions occur in just millionths of a billionth of a second, better known in the scientific world as femtoseconds. Even today's most sophisticated technology can't capture something so short-lived, though some come close. In the last twenty years, scientists have used ultra-fast lasers like fast-action cameras, snapping rapid images of reactions as they occur. But they can't capture the whole picture. "Most of the time," Ni said, "you just see that the reactants disappear and the products appear in a time that you can measure. There was no direct measurement of what actually happened in these chemical reactions." Until now.
Ni's ultracold temperatures force reactions to a comparatively numbed speed. "Because [the molecules] are so cold," Ni said, "now we kind of have a bottleneck effect." When she and her team reacted two potassium rubidium molecules -- chosen for their pliability -- the ultracold temperatures forced the molecules to linger in the intermediate stage for microseconds. Microseconds -- mere millionths of a second -- may seem short, but that's millions of times longer than usual and long enough for Ni and her team to investigate the phase when bonds break and form, in essence, how one molecule turns into another.
With this intimate vision, Ni said she and her team can test theories that predict what happens in a reaction's black hole to confirm if they got it right. Then, her team can craft new theories, using actual data to more precisely predict what happens during other chemical reactions, even those that take place in the mysterious quantum realm.
Read more at Science Daily
"Probably in the next couple of years, we are the only lab that can do this," said Ming-Guang Hu, a postdoctoral scholar in the Ni lab and first author on their paper published today in Science. Five years ago, Ni, the Morris Kahn Associate Professor of Chemistry and Chemical Biology and a pioneer of ultracold chemistry, set out to build a new apparatus that could achieve the lowest temperature chemical reactions of any currently available technology. But they couldn't be sure their intricate engineering would work.
Now, they not only performed the coldest reaction yet, they discovered their new apparatus can do something even they did not predict. In such intense cold -- 500 nanokelvin or just a few millionths of a degree above absolute zero -- their molecules slowed to such glacial speeds, Ni and her team could see something no one has been able to see before: the moment when two molecules meet to form two new molecules. In essence, they captured a chemical reaction in its most critical and elusive act.
Chemical reactions are responsible for literally everything: breathing, cooking, digesting, creating energy, pharmaceuticals, and household products like soap. So, understanding how they work at a fundamental level could help researchers design combinations the world has never seen. With an almost infinite number of new combinations possible, these new molecules could have endless applications from more efficient energy production to new materials like mold-proof walls and even better building blocks for quantum computers.
In her previous work, Ni used colder and colder temperatures to work this chemical magic: forging molecules from atoms that would otherwise never react. Cooled to such extremes, atoms and molecules slow to a quantum crawl, their lowest possible energy state. There, Ni can manipulate molecular interactions with utmost precision. But even she could only see the start of her reactions: two molecules go in, but then what? What happened in the middle and the end was a black hole only theories could try to explain.
Chemical reactions occur in just millionths of a billionth of a second, better known in the scientific world as femtoseconds. Even today's most sophisticated technology can't capture something so short-lived, though some come close. In the last twenty years, scientists have used ultra-fast lasers like fast-action cameras, snapping rapid images of reactions as they occur. But they can't capture the whole picture. "Most of the time," Ni said, "you just see that the reactants disappear and the products appear in a time that you can measure. There was no direct measurement of what actually happened in these chemical reactions." Until now.
Ni's ultracold temperatures force reactions to a comparatively numbed speed. "Because [the molecules] are so cold," Ni said, "now we kind of have a bottleneck effect." When she and her team reacted two potassium rubidium molecules -- chosen for their pliability -- the ultracold temperatures forced the molecules to linger in the intermediate stage for microseconds. Microseconds -- mere millionths of a second -- may seem short, but that's millions of times longer than usual and long enough for Ni and her team to investigate the phase when bonds break and form, in essence, how one molecule turns into another.
With this intimate vision, Ni said she and her team can test theories that predict what happens in a reaction's black hole to confirm if they got it right. Then, her team can craft new theories, using actual data to more precisely predict what happens during other chemical reactions, even those that take place in the mysterious quantum realm.
Read more at Science Daily
Dec 1, 2019
Vision: Not seeing the trees for the wood
Researchers from the Netherlands Institute for Neuroscience have shown how it is possible that objects stand out less when they are surrounded by similar objects. This surround-suppression effect is caused by feedback from higher visual brain areas. The results of this research are important for a better understanding of the way in which the brain transforms incoming light into a cohesive image. The paper has been published in the scientific journal Current Biology.
The brain area responsible for processing vision is located at the back of the brain. One of the most important parts of this area, the primary visual cortex, is the area where a visual stimulus first reaches the cortex. Nerve cells in this area are sensitive to perceiving objects within a very small field of vision. So when you look at a specific object, the nerve cells in the primary cortex are activated and you see this object. "But when this object is surrounded by similar objects, the cells are less active. So really what happens is that you don't see the trees for the wood," says Alexander Heimel, group leader at the Netherlands Institute.
SURROUND-SUPPRESSION EFFECT
"The theory had previously yielded the idea that this surround-suppression effect was the result of signals from higher visual brain areas. But until recently there was not much scientific evidence for this," says principal researcher Joris Vangeneugden, aios at Maastricht University. In order to find out whether it really was a matter of higher visual brain areas signaling, the researchers measured mouse brain activity while the mouse was looking at images of different sizes. At the same time, the researchers managed to pause the higher visual areas for a couple of seconds. It turned out that the activity in the primary visual cortex remained high for the larger images when these higher visual areas were paused, while this did not happen when they were active. The suppression of the surroundings thus decreased. This shows that the higher areas do indeed provide some sort of feedback to the primary visual cortex. "They tell the primary visual cortex that it should focus on a small individual object, not on everything there is to see," says Heimel.
VISUAL PROTHESIS
Understanding this step is necessary to understand, eventually, how the brain transforms the light that enters via our eyes into a perception that makes us understand what we see. "An understanding of how our brain does this is essential for the development of prosthetics that will make blind people see again. Merely ensuring that light reaches the brain does not always suffice; what happens after that is even more important," says Vangeneugden.
From Science Daily
The brain area responsible for processing vision is located at the back of the brain. One of the most important parts of this area, the primary visual cortex, is the area where a visual stimulus first reaches the cortex. Nerve cells in this area are sensitive to perceiving objects within a very small field of vision. So when you look at a specific object, the nerve cells in the primary cortex are activated and you see this object. "But when this object is surrounded by similar objects, the cells are less active. So really what happens is that you don't see the trees for the wood," says Alexander Heimel, group leader at the Netherlands Institute.
SURROUND-SUPPRESSION EFFECT
"The theory had previously yielded the idea that this surround-suppression effect was the result of signals from higher visual brain areas. But until recently there was not much scientific evidence for this," says principal researcher Joris Vangeneugden, aios at Maastricht University. In order to find out whether it really was a matter of higher visual brain areas signaling, the researchers measured mouse brain activity while the mouse was looking at images of different sizes. At the same time, the researchers managed to pause the higher visual areas for a couple of seconds. It turned out that the activity in the primary visual cortex remained high for the larger images when these higher visual areas were paused, while this did not happen when they were active. The suppression of the surroundings thus decreased. This shows that the higher areas do indeed provide some sort of feedback to the primary visual cortex. "They tell the primary visual cortex that it should focus on a small individual object, not on everything there is to see," says Heimel.
VISUAL PROTHESIS
Understanding this step is necessary to understand, eventually, how the brain transforms the light that enters via our eyes into a perception that makes us understand what we see. "An understanding of how our brain does this is essential for the development of prosthetics that will make blind people see again. Merely ensuring that light reaches the brain does not always suffice; what happens after that is even more important," says Vangeneugden.
From Science Daily
Placenta changes could mean male offspring of older moms more likely to develop heart problems
Placenta changes could mean male offspring of older mums more likely to develop heart problems in later life, rat study finds.
Changes occur in the placenta in older pregnant mothers leading to a greater likelihood of poor health in their male offspring, a study in rats has shown. Both male and female fetuses do not grow as large in older mothers, but there are sex-specific differences in changes to placental development and function. These are likely to play a central role in the increased likelihood of later-life heart problems and high blood pressure in males.
In humans, women over 35 are considered to be of advanced maternal age. The study, published in Scientific Reports, looked at pregnant rats of a comparable age. In aged mothers, the placenta of female fetuses showed beneficial changes in structure and function that would maximise the support of fetal growth. In some instances, the placenta even supported the female fetus better than the placenta of a younger mother. In the case of male fetuses however, the placenta showed changes that would limit fetal growth in the aged pregnant rats.
"This new understanding of placental development and function could contribute to better management of human pregnancies, and development of targeted interventions to improve the longer-term health of children born to older mothers," said Dr Tina Napso, a postdoctoral fellow at the University of Cambridge and first author of the study.
Pregnancy in older mothers is associated with a heightened risk of complications for both the mother and her baby. These include preeclampsia -- raised blood pressure in the mother during pregnancy, gestational diabetes, stillbirth and fetal growth restriction. Until now there has been limited understanding of how the placenta is altered by advanced maternal age.
"With the average age of first pregnancy in women becoming higher and higher, and especially so in developed countries, it is very important to understand how the age of the mother and the sex of the baby interact to determine pregnancy and later-life health of the child," said Dr Amanda Sferruzzi-Perri, lead author of the study and a Royal Society Fellow in the Centre for Trophoblast Research at the University of Cambridge's Department of Physiology, Development and Neuroscience.
The placenta transports nutrients and oxygen from mother to fetus, secretes signalling factors into the mother so she supports fetal development, and is the main protective barrier for the fetus against toxins, bacteria, and hormones -- such as stress hormones -- in the mother's blood. It is highly dynamic in nature, and its function can change to help protect the growing fetus when conditions become less favourable for its development, for example through a lack of nutrients or oxygen or when the mother is stressed.
The researchers analysed the placentas of young (3-4 months old) and aged rats (9.5-10 months old) that were pregnant with male and female offspring. The aged rats correspond to approximately 35 year-old humans. Rats are a useful model as their biology and physiology have a number of important characteristics in common with those of humans.
The study found that advanced maternal age reduced the efficiency of the placenta of both male and female fetuses. It affected the structure and function of the placenta more markedly for male fetuses, reducing its ability to support growth of the fetus.
"A pregnancy at an older age is a costly proposition for the mother, whose body has to decide how nutrients are shared with the fetus. That's why, overall, fetuses do not grow sufficiently during pregnancy when the mother is older compared to when she is young," said Dr Napso. "We now know that growth, as well as gene expression in the placenta is affected in older mothers in a manner that partially depends on sex: changes in the placentas of male fetuses are generally detrimental."
The research involved a collaboration between scientists at the University of Cambridge, the University of Alberta in Canada, the Robinson Research Institute and the University of Adelaide, Australia.
An earlier study performed by the collaborators showed that offspring from mothers who enter pregnancy at an older age have poor heart function and high blood pressure as young adults, and particularly so if they are male. This new research was conducted to understand why, and whether this sex difference may be due to how the male and female fetuses are supported within the womb in an aged mother.
Read more at Science Daily
Changes occur in the placenta in older pregnant mothers leading to a greater likelihood of poor health in their male offspring, a study in rats has shown. Both male and female fetuses do not grow as large in older mothers, but there are sex-specific differences in changes to placental development and function. These are likely to play a central role in the increased likelihood of later-life heart problems and high blood pressure in males.
In humans, women over 35 are considered to be of advanced maternal age. The study, published in Scientific Reports, looked at pregnant rats of a comparable age. In aged mothers, the placenta of female fetuses showed beneficial changes in structure and function that would maximise the support of fetal growth. In some instances, the placenta even supported the female fetus better than the placenta of a younger mother. In the case of male fetuses however, the placenta showed changes that would limit fetal growth in the aged pregnant rats.
"This new understanding of placental development and function could contribute to better management of human pregnancies, and development of targeted interventions to improve the longer-term health of children born to older mothers," said Dr Tina Napso, a postdoctoral fellow at the University of Cambridge and first author of the study.
Pregnancy in older mothers is associated with a heightened risk of complications for both the mother and her baby. These include preeclampsia -- raised blood pressure in the mother during pregnancy, gestational diabetes, stillbirth and fetal growth restriction. Until now there has been limited understanding of how the placenta is altered by advanced maternal age.
"With the average age of first pregnancy in women becoming higher and higher, and especially so in developed countries, it is very important to understand how the age of the mother and the sex of the baby interact to determine pregnancy and later-life health of the child," said Dr Amanda Sferruzzi-Perri, lead author of the study and a Royal Society Fellow in the Centre for Trophoblast Research at the University of Cambridge's Department of Physiology, Development and Neuroscience.
The placenta transports nutrients and oxygen from mother to fetus, secretes signalling factors into the mother so she supports fetal development, and is the main protective barrier for the fetus against toxins, bacteria, and hormones -- such as stress hormones -- in the mother's blood. It is highly dynamic in nature, and its function can change to help protect the growing fetus when conditions become less favourable for its development, for example through a lack of nutrients or oxygen or when the mother is stressed.
The researchers analysed the placentas of young (3-4 months old) and aged rats (9.5-10 months old) that were pregnant with male and female offspring. The aged rats correspond to approximately 35 year-old humans. Rats are a useful model as their biology and physiology have a number of important characteristics in common with those of humans.
The study found that advanced maternal age reduced the efficiency of the placenta of both male and female fetuses. It affected the structure and function of the placenta more markedly for male fetuses, reducing its ability to support growth of the fetus.
"A pregnancy at an older age is a costly proposition for the mother, whose body has to decide how nutrients are shared with the fetus. That's why, overall, fetuses do not grow sufficiently during pregnancy when the mother is older compared to when she is young," said Dr Napso. "We now know that growth, as well as gene expression in the placenta is affected in older mothers in a manner that partially depends on sex: changes in the placentas of male fetuses are generally detrimental."
The research involved a collaboration between scientists at the University of Cambridge, the University of Alberta in Canada, the Robinson Research Institute and the University of Adelaide, Australia.
An earlier study performed by the collaborators showed that offspring from mothers who enter pregnancy at an older age have poor heart function and high blood pressure as young adults, and particularly so if they are male. This new research was conducted to understand why, and whether this sex difference may be due to how the male and female fetuses are supported within the womb in an aged mother.
Read more at Science Daily
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