Using static electricity, microrobots can land and stick to surfaces

Call them the RoboBats. In a recent article in Science, Harvard roboticists demonstrate that their flying microrobots, nicknamed the RoboBees, can now perch during flight to save energy -- like bats, birds or butterflies.

"Many applications for small drones require them to stay in the air for extended periods," said Moritz Graule, first author of the paper who conducted this research as a student at the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) and Wyss Institute for Biologically Inspired Engineering at Harvard University. "Unfortunately, smaller drones run out of energy quickly. We want to keep them aloft longer without requiring too much additional energy."

The team found inspiration in nature and simple science.

"A lot of different animals use perching to conserve energy," said Kevin Ma, a post-doc at SEAS and the Wyss Institute and coauthor. "But the methods they use to perch, like sticky adhesives or latching with talons, are inappropriate for a paperclip-size microrobot, as they either require intricate systems with moving parts or high forces for detachment."

Instead, the team turned to electrostatic adhesion -- the same basic science that causes a static-charged sock to cling to a pants leg or a balloon to stick to a wall.

When you rub a balloon on a wool sweater, the balloon becomes negatively charged. If the charged balloon is brought close to a wall, that negative charge forces some of the wall's electrons away, leaving the surface positively charged. The attraction between opposite charges then causes the balloon to stick to the wall.

"In the case of the balloon, however, the charges dissipate over time, and the balloon will eventually fall down," said Graule. "In our system, a small amount of energy is constantly supplied to maintain the attraction."

The RoboBee, pioneered at the Harvard Microrobotics Lab, uses an electrode patch and a foam mount that absorbs shock. The entire mechanism weighs 13.4 mg, bringing the total weight of the robot to about 100mg -- similar to the weight of a real bee. The robot takes off and flies normally. When the electrode patch is supplied with a charge, it can stick to almost any surface, from glass to wood to a leaf. To detach, the power supply is simply switched off.

"One of the biggest advantages of this system is that it doesn't cause destabilizing forces during disengagement, which is crucial for a robot as small and delicate as ours," said Graule.

The patch requires about 1000 times less power to perch than it does to hover, offering to dramatically extend the operational life of the robot. Reducing the robot's power requirements is critical for the researchers, as they work to integrate onboard batteries on untethered RoboBees.

"The use of adhesives that are controllable without complex physical mechanisms, are low power, and can adhere to a large array of surfaces is perfect for robots that are agile yet have limited payload -- like the RoboBee," added Robert Wood, Charles River Professor of Engineering and Applied Sciences at SEAS and a core faculty member of the Wyss Institute, and senior author of the study. "When making robots the size of insects, simplicity and low power are always key constraints."

Right now, the RoboBee can only perch under overhangs and on ceilings, as the electrostatic patch is attached to the top of the vehicle. Next, the team hopes to change the mechanical design so that the robot can perch on any surface.

"There are more challenges to making a robust, robotic landing system but this experimental result demonstrates a very versatile solution to the problem of keeping flying microrobots operating longer without quickly draining power," said Ma.

Video: https://www.youtube.com/watch?v=GJecMPiEGuA

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The above post is reprinted from materials provided by Harvard John A. Paulson School of Engineering and Applied Sciences. The original item was written by Leah Burrows. Note: Materials may be edited for content and length.

Archaeologists uncover 13,000-year-old bones of ancient, extinct species of bison at Old Vero Man site

In what is considered one of the oldest and most important archaeological digs in North America, scientists have uncovered what they believe are the bones of a 13,000- to 14,000-year-old ancient, extinct species of bison at the Old Vero Man Site in Vero Beach, Fla. Archaeologists from Florida Atlantic University's Harbor Branch Oceanographic Institute made this discovery just 10 feet below the ground's surface during the final stretch of the 2016 excavation efforts at the Vero Beach site.

Climate change may have contributed to extinction of Neanderthals

A researcher at the University of Colorado Denver has found that Neanderthals in Europe showed signs of nutritional stress during periods of extreme cold, suggesting climate change may have contributed to their demise around 40,000 years ago.

Jamie Hodgkins, a zooarchaeologist and assistant professor in the Department of Anthropology at CU Denver, analyzed the remains of prey animals and found that Neanderthals worked especially hard to extract every calorie from the meat and bones during colder time periods. Her results were published in the Journal of Human Evolution last week.

Hodgkins examined bones discovered in caves once inhabited by Neanderthals in southwestern France for marks demonstrating how the carcasses of deer and other animals were butchered and used for food. During colder, glacial periods, the bones were more heavily processed. In particular, they showed higher frequencies of percussion marks, indicating a nutritional need to consume all of the marrow, probably signaling reduced food availability.

"Our research uncovers a pattern showing that cold, harsh environments were stressful for Neanderthals," said Hodgkins. "As the climate got colder, Neanderthals had to put more into extracting nutrients from bones. This is especially apparent in evidence that reveals Neanderthals attempted to break open even low marrow yield bones, like the small bones of the feet."

These findings further support the hypothesis that changing climate was a factor in Neanderthal extinction.

"Our results illustrate that climate change has real effects," said Hodgkins. "Studying Neanderthal behavior is an opportunity to understand how a rapidly changing climate affected our closest human relatives in the past. If Neanderthal populations were already on the edge of survival at the end of the Ice Age, the increased competition that occurred when modern humans appeared on the scene may have pushed them over the edge."

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The above post is reprinted from materials provided by University of Colorado Denver. Note: Materials may be edited for content and length.

How the spectacular Hawaiian-Emperor seamount chain became so bendy

The physical mechanism causing the unique, sharp bend in the Hawaiian-Emperor seamount chain has been uncovered in a collaboration between the University of Sydney and the California Institute of Technology (Caltech).

Mysterious mounds created by earthworms

Mysterious spectacular mounds found in Earth in tropical wetlands in South America are created by earthworms, researchers have found.

A quasiparticle collider

In the early 1900s, Ernest Rutherford shot alpha particles onto gold foils and concluded from their scattering properties that atoms contain their mass in a very small nucleus. A hundred years later, modern scientists took that concept to a new level, building the Large Hadron Collider in Switzerland to smash protons into each other, which led to the discovery of the Higgs boson.

Paper gets 'smart' with drawn-on, stenciled sensor tags

A piece of paper is one of the most common, versatile daily items. Children use it to draw their favorite animals and practice writing the A-B-Cs, and adults print reports or scribble a hasty grocery list.

Swept up in the solar wind

From our vantage point on the ground, the sun seems like a still ball of light, but in reality, it teems with activity. Eruptions called solar flares and coronal mass ejections explode in the sun's hot atmosphere, the corona, sending light and high energy particles out into space. The corona is also constantly releasing a stream of charged particles known as the solar wind.

'Sixth sense' protects drivers except when texting

While much has been made about the dangers of texting and driving, less attention has been focused on the age-old distractions of being absent minded or upset while driving. A team of researchers from the University of Houston (UH) and the Texas A&M Transportation Institute (TTI) focused on all three of these important factors.

Chemists find 'huge shortcut' for organic synthesis using C-H bonds

Chemists have taken another major step in the quest to use carbon-hydrogen bonds to create new molecules, a strategy that aims to revolutionize the field of organic synthesis.

Exoplanets' complex orbital structure points to planetary migration in solar systems

The four planets of the Kepler-223 star system seem to have little in common with the planets of Earth's own solar system. And yet a new study shows that the Kepler-223 system is trapped in an orbital configuration that Jupiter, Saturn, Uranus, and Neptune may have broken from in the early history of the solar system.

Twin study finds that gut microbiomes run in families

A genome-wide association analysis of over 1,000 twins in the UK supports that some parts of our microbiomes are inherited and shaped--not through a spread of microbes from parent to child, but through our genes. The results, revealing new examples of heritable bacterial species--including those related to diet preference, metabolism, and immune defense -- appear May 11 in Cell Host & Microbe's special issue on the "Genetics and Epigenetics of Host-Microbe Interactions."

Cosmic dust reveals Earth's ancient atmosphere

Using the oldest fossil micrometeorites -- space dust -- ever found, Monash University-led research has made a surprising discovery about the chemistry of Earth's atmosphere 2.7 billion years ago.

The findings of a new study published today in the journal Nature -- led by Dr Andrew Tomkins and a team from the School of Earth, Atmosphere and Environment at Monash, along with scientists from the Australian Synchrotron and Imperial College, London -- challenge the accepted view that Earth's ancient atmosphere was oxygen-poor. The findings indicate instead that the ancient Earth's upper atmosphere contained about the same amount of oxygen as today, and that a methane haze layer separated this oxygen-rich upper layer from the oxygen-starved lower atmosphere.

Dr Tomkins explained how the team extracted micrometeorites from samples of ancient limestone collected in the Pilbara region in Western Australia and examined them at the Monash Centre for Electron Microscopy (MCEM) and the Australian Synchrotron.

"Using cutting-edge microscopes we found that most of the micrometeorites had once been particles of metallic iron -- common in meteorites -- that had been turned into iron oxide minerals in the upper atmosphere, indicating higher concentrations of oxygen than expected," Dr Tomkins said.

"This was an exciting result because it is the first time anyone has found a way to sample the chemistry of the ancient Earth's upper atmosphere," Dr Tomkins said.

Imperial College researcher Dr Matthew Genge -- an expert in modern cosmic dust -- performed calculations that showed oxygen concentrations in the upper atmosphere would need to be close to modern day levels to explain the observations.

"This was a surprise because it has been firmly established that the Earth's lower atmosphere was very poor in oxygen 2.7 billion years ago; how the upper atmosphere could contain so much oxygen before the appearance of photosynthetic organisms was a real puzzle," Dr Genge said.

Dr Tomkins explained that the new results suggest the Earth at this time may have had a layered atmosphere with little vertical mixing, and higher levels of oxygen in the upper atmosphere produced by the breakdown of CO 2 by ultraviolet light.

"A possible explanation for this layered atmosphere might have involved a methane haze layer at middle levels of the atmosphere. The methane in such a layer would absorb UV light, releasing heat and creating a warm zone in the atmosphere that would inhibit vertical mixing," Dr Tomkins said.

"It is incredible to think that by studying fossilised particles of space dust the width of a human hair, we can gain new insights into the chemical makeup of Earth's upper atmosphere, billions of years ago." Dr Tomkins said.

Dr Tomkins outlined next steps in the research.

"The next stage of our research will be to extract micrometeorites from a series of rocks covering over a billion years of Earth's history in order to learn more about changes in atmospheric chemistry and structure across geological time. We will focus particularly on the great oxidation event, which happened 2.4 billion years ago when there was a sudden jump in oxygen concentration in the lower atmosphere."

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The above post is reprinted from materials provided by Monash University.Note: Materials may be edited for content and length.

Optical Illusion Zebra Crossings Are Appearing In India

How do you slow down a car without using speed bumps? Assuming you haven’t got access to some sort of powerful magnetic device or your own superpowers, the answer may be to use some extremely clever artists. 3D street art is becoming increasingly commonplace these days, but it takes an incredible artist to produce. Normally it’s made for purely aesthetic reasons, but every now and then, there’s a plan behind the painting. With this in mind, artists Saumya Pandya Thakkar and Shakuntala Pandya of Ahmedabad, India have recently taken to social media to share their latest creations: optical illusions that look very much like zebra crossings. The hope is to use them to reduce the speed of vehicles in population-dense areas.

Fructose alters hundreds of brain genes, which can lead to a wide range of diseases

A range of diseases -- from diabetes to cardiovascular disease, and from Alzheimer's disease to attention deficit hyperactivity disorder -- are linked to changes to genes in the brain. A new study by UCLA life scientists has found that hundreds of those genes can be damaged by fructose, a sugar that's common in the Western diet, in a way that could lead to those diseases.

However, the researchers discovered good news as well: An omega-3 fatty acid known as docosahexaenoic acid, or DHA, seems to reverse the harmful changes produced by fructose.

"DHA changes not just one or two genes; it seems to push the entire gene pattern back to normal, which is remarkable," said Xia Yang, a senior author of the study and a UCLA assistant professor of integrative biology and physiology. "And we can see why it has such a powerful effect."

DHA occurs naturally in the membranes of our brain cells, but not in a large enough quantity to help fight diseases.

"The brain and the body are deficient in the machinery to make DHA; it has to come through our diet," said Fernando Gomez-Pinilla, a UCLA professor of neurosurgery and of integrative biology and physiology, and co-senior author of the paper.

DHA strengthens synapses in the brain and enhances learning and memory. It is abundant in wild salmon (but not in farmed salmon) and, to a lesser extent, in other fish and fish oil, as well as walnuts, flaxseed, and fruits and vegetables, said Gomez-Pinilla, who also is a member of UCLA's Brain Injury Research Center.

Americans get most of their fructose in foods that are sweetened with high-fructose corn syrup, an inexpensive liquid sweetener made from corn starch, and from sweetened drinks, syrups, honey and desserts. The Department of Agriculture estimates that Americans consumed an average of about 27 pounds of high-fructose corn syrup in 2014. Fructose is also found is in most baby food and in fruit, although the fiber in fruit substantially slows the body's absorption of the sugar -- and fruit contains other healthy components that protect the brain and body, Yang said.

To test the effects of fructose and DHA, the researchers trained rats to escape from a maze, and then randomly divided the animals into three groups. For the next six weeks, one group of rats drank water with an amount of fructose that would be roughly equivalent to a person drinking a liter of soda per day. The second group was given fructose water and a diet rich in DHA. The third received water without fructose and no DHA.

After the six weeks, the rats were put through the maze again. The animals that had been given only the fructose navigated the maze about half as fast than the rats that drank only water -- indicating that the fructose diet had impaired their memory. The rats that had been given fructose and DHA, however, showed very similar results to those that only drank water -- which strongly suggests that the DHA eliminated fructose's harmful effects.

Other tests on the rats revealed more major differences: The rats receiving a high-fructose diet had much higher blood glucose, triglycerides and insulin levels than the other two groups. Those results are significant because in humans, elevated glucose, triglycerides and insulin are linked to obesity, diabetes and many other diseases.

The research team sequenced more than 20,000 genes in the rats' brains, and identified more than 700 genes in the hypothalamus (the brain's major metabolic control center) and more than 200 genes in the hippocampus (which helps regulate learning and memory) that were altered by the fructose. The altered genes they identified, the vast majority of which are comparable to genes in humans, are among those that interact to regulate metabolism, cell communication and inflammation. Among the conditions that can be caused by alterations to those genes are Parkinson's disease, depression, bipolar disorder, and other brain diseases, said Yang, who also is a member of UCLA's Institute for Quantitative and Computational Biosciences.

Of the 900 genes they identified, the researchers found that two in particular, called Bgn and Fmod, appear to be among the first genes in the brain that are affected by fructose. Once those genes are altered, they can set off a cascade effect that eventually alters hundreds of others, Yang said.

That could mean that Bgn and Fmod would be potential targets for new drugs to treat diseases that are caused by altered genes in the brain, she added.

The research also uncovered new details about the mechanism fructose uses to disrupt genes. The scientists found that fructose removes or adds a biochemical group to cytosine, one of the four nucleotides that make up DNA. (The others are adenine, thymine and guanine.) This type of modification plays a critical role in turning genes "on" or "off."

The research is published online in EBioMedicine, a journal published jointly by Cell and The Lancet. It is the first genomics study of all the genes, pathways and gene networks affected by fructose consumption in the regions of the brain that control metabolism and brain function.

Previous research led by Gomez-Pinilla found that fructose damages communication between brain cells and increases toxic molecules in the brain; and that a long-term high-fructose diet diminishes the brain's ability to learn and remember information.

"Food is like a pharmaceutical compound that affects the brain," said Gomez-Pinilla. He recommends avoiding sugary soft drinks, cutting down on desserts and generally consuming less sugar and saturated fat.

Although DHA appears to be quite beneficial, Yang said it is not a magic bullet for curing diseases. Additional research will be needed to determine the extent of its ability to reverse damage to human genes.

The paper's lead author is Qingying Meng, a postdoctoral scholar in Yang's laboratory. Other co-authors are Zhe Ying, a staff research associate in Gomez-Pinilla's laboratory, and colleagues from UCLA, the National Institutes of Health and Icahn School of Medicine at Mount Sinai in New York.

Yang's research is supported by the National Institutes of Health (grant R01DK104363), as is Gomez-Pinilla's (R01DK104363 and R01NS050465).

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The above post is reprinted from materials provided by University of California - Los Angeles. Note: Materials may be edited for content and length.

Researchers pinpoint part of the brain that recognizes facial expressions

Researchers at The Ohio State University have pinpointed the area of the brain responsible for recognizing human facial expressions.

It's on the right side of the brain behind the ear, in a region called the posterior superior temporal sulcus (pSTS).

In a paper published today in the Journal of Neuroscience, the researchers report that they used functional magnetic resonance imaging (fMRI) to identify a region of pSTS as the part of the brain activated when test subjects looked at images of people making different facial expressions.

Further, the researchers have discovered that neural patterns within the pSTS are specialized for recognizing movement in specific parts of the face. One pattern is tuned to detect a furrowed brow, another is tuned to detect the upturn of lips into a smile, and so on.

"That suggests that our brains decode facial expressions by adding up sets of key muscle movements in the face of the person we are looking at," said Aleix Martinez, a cognitive scientist and professor of electrical and computer engineering at Ohio State.

Martinez said that he and his team were able to create a machine learning algorithm that uses this brain activity to identify what facial expression a person is looking at based solely on the fMRI signal.

"Humans use a very large number of facial expressions to convey emotion, other non-verbal communication signals and language," Martinez said.

"Yet, when we see someone make a face, we recognize it instantly, seemingly without conscious awareness. In computational terms, a facial expression can encode information, and we've long wondered how the brain is able to decode this information so efficiently.

"Now we know that there is a small part of the brain devoted to this task."

Using this fMRI data, the researchers developed a machine learning algorithm that has about a 60 percent success rate in decoding human facial expressions, regardless of the facial expression and regardless of the person viewing it.

"That's a very powerful development, because it suggests that the coding of facial expressions is very similar in your brain and my brain and most everyone else's brain," Martinez said.

The study doesn't say anything about people who exhibit atypical neural functioning, but it could give researchers new insights, said study co-author Julie Golomb, assistant professor of psychology and director of the Vision and Cognitive Neuroscience Lab at Ohio State.

"This work could have a variety of applications, helping us not only understand how the brain processes facial expressions, but ultimately how this process may differ in people with autism, for example," she said.

Doctoral student Ramprakash Srinivasan, Golomb and Martinez placed 10 college students into an fMRI machine and showed them more than 1,000 photographs of people making facial expressions. The expressions corresponded to seven different emotional categories: disgusted, happily surprised, happily disgusted, angrily surprised, fearfully surprised, sadly fearful and fearfully disgusted.

While some of the expressions were positive and others negative, they all had some commonalities among them. For instance, "happily surprised," "angrily surprised" and "fearfully surprised" all include raised eyebrows, though other parts of the face differ when we express these three emotions.

fMRI detects increased blood flow in the brain, so the research group was able to obtain images of the part of the brain that was activated when the students recognized different expressions. Regardless of the expression they were looking at, all the students showed increased activity in the same region -- the pSTS.

Then the research group used a computer to cross-reference the fMRI images with the different facial muscle movements shown in the test photographs. They were able to create a map of regions within the pSTS that activated for different facial muscle groups, such as the muscles of the eyebrows or lips.

First, they constructed maps using the fMRIs of 9 of the participants. Then, they fed the algorithm the fMRI images from the 10th student, and asked it to identify the expressions that student was looking at. Then they repeated the experiment, creating the map from scratch with data from nine of the students, but using a different student as the 10th subject.

About 60 percent of the time, the algorithm was able to accurately identify the facial expression that the 10th person was looking at, based solely on that person's fMRI image.

Martinez called the results "very positive," and said that they indicate that the algorithm is making strides toward an understanding of what happens in that region of the brain.

The researchers will continue the work, which was funded by the National Institutes of Health and the Alfred P. Sloan Foundation.

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The above post is reprinted from materials provided by Ohio State University. The original item was written by Pam Frost Gorder. Note: Materials may be edited for content and length.

Cracking the Zika mystery

An important breakthrough in understanding the Zika virus structure and its behaviour has been highlighted in a study by Duke-NUS Medical School (Duke-NUS) scientists.

Published online on 19 April 2016 in the journal Nature, their findings reveal the Zika virus structure and identify potential sites on the virus to target with therapeutics. This knowledge will help worldwide efforts to fight the poorly understood virus, which is a currently a public health and research priority.

Associate Professor Shee-Mei Lok and her team from Duke-NUS imaged the Zika virus under a cryo-electron microscope from a large number of purified viral particles. By using thousands of images, they reconstructed a high-resolution cryo-electron microscopy structure of the Zika virus.

The high-resolution structure of the Zika virus showed that the overall virus architecture is similar to other flaviviruses such as the West Nile and dengue viruses. However, the team found that the Zika virus is more thermally stable than the dengue virus, and is also structurally stable even when incubated at 40 degrees Celsius, mimicking the body temperature of extremely feverish patients after virus infection.

The structure also revealed that the Zika virus surface proteins have tighter interactions compared to the dengue virus, therefore making it more stable than the dengue virus. This may explain its ability to survive in harsh conditions such as semen, saliva and urine. In addition to transmission by the bite of an infected mosquito, the structural stability of the virus makes it more resilient, which likely explains its special ability to transmit through sexual contact. Similar viruses, such as dengue and West Nile, do not spread through sexual contact.

Overall, the findings suggest that antibodies or drugs that destabilise the structure of the Zika virus may help to reduce the severity of the disease or limit the spread of the virus.

"This is exciting, as our structure will provide important clues to other researchers around the world who are working to find therapeutic agents against the Zika virus," said Assoc Prof Lok from the Emerging Infectious Diseases Programme at Duke-NUS.

"Additionally, we have shown that the Zika virus contains structures that are unique from the viruses in the same family that affect brains, such as the West Nile virus, and also those that cause fever, such as the dengue virus. These structures can be mutated to better understand how they influence the Zika virus infection in humans and can also potentially lead to the development of a safe vaccine that has reduced side effects."

Assoc Prof Lok's next step is to understand the effect of potent antibodies on the Zika virus. By examining the structure presented in this study, her team will work to determine how the antibodies could be used to kill the virus. They also hope to identify which potent antibodies could be used to treat people in emergency situations, such as a sudden outbreak or in the case of infection during pregnancy.

The authors include Dr Victor Kostyuchenko, Elisa Lim and Dr Shuijun Zhang from Duke-NUS.

The Zika virus, a mosquito-borne virus, is mainly transmitted to people through the bite of infected Aedes mosquitoes. It causes Zika virus disease which presents symptoms such as mild fever, skin rashes, conjunctivitis, muscle and joint pain, malaise or headache in infected people.

In February 2016, the Zika virus was declared by the World Health Organization (WHO) to be a public health emergency of international concern. (1) This was a result of worldwide outbreaks of the virus starting in 2013 which have been associated with neurological disorders such as microcephaly in foetuses and Guillian-Barré syndrome in adults. (2)

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(1) WHO statement on the first meeting of the International Health Regulations (2005) (IHR 2005) Emergency Committee on Zika virus and observed increase in neurological disorders and neonatal malformations. (2016, February 1). Retrieved April 13, 2016, fromhttp://www.who.int/mediacentre/news/statements/2016/1st-emergency-committee-zika/en/

(2) Zika virus. (n.d.). Retrieved April 13, 2016, fromhttp://www.who.int/mediacentre/factsheets/zika/en/

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The above post is reprinted from materials provided by Duke-NUS Medical School. Note: Materials may be edited for content and length

Astrophysicists find triple star system with 'hot Jupiter'

Crisp, clear images of a "hot Jupiter" system captured by a University of Notre Dame physicist were vital in determining that a newly found planet inhabits a three-star system, a phenomenon documented only a few times before.

Origin of life: An artificial comet holds the missing piece

Researchers have for the first time shown that ribose, a sugar that is one of the building blocks of genetic material in living organisms, may have formed in cometary ices. To obtain this result, scientists at the Institut de Chimie de Nice (CNRS/Université Nice Sophia Antipolis) carried out a highly detailed analysis of an artificial comet created by their colleagues at the Institut d'Astrophysique Spatiale (CNRS/Université Paris-Sud). Along with other teams[1], including one at the SOLEIL synchrotron, they propose the first realistic scenario for the formation of this key compound, which had never been detected in meteorites or cometary ices until now. Their findings, which shed new light on the emergence of life on Earth, are published in the journal Science dated 8 April 2016.

First transistors made entirely of nanocrystal 'inks'

The transistor is the most fundamental building block of electronics, used to build circuits capable of amplifying electrical signals or switching them between the 0s and 1s at the heart of digital computation. Transistor fabrication is a highly complex process, however, requiring high-temperature, high-vacuum equipment.