Sunday, August 19, 2018

Team Develops New Way To Grow Blood Vessels

Formation of new blood vessels, a process also known as angiogenesis, is one of the major clinical challenges in wound healing and tissue implants. To address this issue, researchers from Texas A&M University have developed a clay-based platform to deliver therapeutic proteins to the body to assist with the formation of blood vessels.

The team is led by members of the Inspired Nanomaterials and Tissue Engineering Lab in the Department of Biomedical Engineering. They have developed technology that introduces a new type of two-dimensional clay, also known as nanosilicates, that delivers multiple specialized proteins called growth factors into the body to stimulate new blood vessel formation. To allow blood vessels time to form, the clay is designed to prolong the release through its high surface area and charged characteristics, according to biomedical engineering assistant professor Dr. Akhilesh K. Gaharwar.

A photo of research conducted by Dr. Akhilesh Gaharwar and his team to develop a new platform to form blood vessels
Credit: Texas A&M University

"Clay nanoparticles work like tiny weak magnets that hold the growth factors within the polymeric hydrogels and release very slowly," Gaharwar said. "Sustained and prolonged release of physiologically relevant doses of growth factors are important to avoid problems due to high doses, such as abrupt tissue formation."

Co-investigator Dr. Kayla Bayless from the Department of Molecular and Cellular Medicine in the Texas A&M Health Science Center said the clay also keeps the growth factors organized, preventing abnormal growth and moderating activity of surrounding cells.

Gaharwar said by establishing clay nanoparticles as a platform technology for delivering the growth factors, the research will have a significant impact on designing the next generation of bioactive scaffolds and implants.

The research was recently published in Advanced Biosystems and is funded by the Division of Chemical, Bioengineering, Environmental and Transport Systems of the National Institute of Science, the National Institute of Biomedical Imaging and Bioengineering of the National Institutes of Health and by the National Science Foundation.


Contacts and sources:
Aubrey BloomTexas A&M University


Citation: 2D Nanosilicates Loaded with Proangiogenic Factors Stimulate Endothelial Sprouting David W. Howell Charles W. Peak Kayla J. Bayless Akhilesh K. Gaharwar First published: 11 June 2018 http://dx.doi.org/10.1002/adbi.201800092  https://onlinelibrary.wiley.com/doi/abs/10.1002/adbi.201800092

Scarlet Macaw DNA Points to Ancient Breeding Operation in Southwest

Somewhere in the American Southwest or northern Mexico, there are probably the ruins of a scarlet macaw breeding operation dating to between 900 and 1200 C.E., according to a team of archaeologists who sequenced the mitochondrial DNA of bird remains found in the Chaco Canyon and Mimbres areas of New Mexico.

Remains of a thriving prehistoric avian culture and breeding colony of scarlet macaws exist at the northern Mexican site of Paquimé, or Casas Grande. However, this community existed from 1250 to 1450, well after the abandonment of Chaco Canyon, and could not have supplied these birds to Southwest communities prior to the 13th century, said Richard George, graduate student in anthropology, Penn State.

Scarlet macaw (A.M. cyanoptera) walks on the ground. 
Credit: Lakdos

Historically, scarlet macaws lived from South America to eastern coastal Mexico and Guatemala, thousands of miles from the American Southwest. Previously, researchers thought that ancestral Puebloan people might have traveled to these natural breeding areas and brought birds back, but the logistics of transporting adolescent birds are difficult. None of the sites where these early macaw remains were found contained evidence of breeding -- eggshells, pens or perches.

"We were interested in the prehistoric scarlet macaw population history and the impacts of human direct management," said George. "Especially any evidence for directed breeding or changes in the genetic diversity that could co-occur with different trade networks."

The researchers sequenced the mitochondrial DNA of 20 scarlet macaw specimens, but were only able to obtain full sequences from 14. They then directly radiocarbon-dated all 14 birds with complete or near complete genomes and found they fell between 900 and 1200 CE.

"We looked at the full mitochondrial genome of over 16,000 base pairs to understand the maternal relationships represented in the Chaco Canyon and Mimbres regions," said George.

Early illustration of a scarlet macaw drawn in Illustrations of the Family of Psittacidae, or Parrots, by Edward Lear in 1832. 
Credit:  Edward Lear, PD-US

Mitochondrial DNA exists separate from the cell nucleus and is inherited directly from the mother. While nuclear DNA combines the DNA inherited from both parents, mitochondrial DNA can show direct lineage because all siblings have the same mtDNA as their mother, and she has the same mtDNA as her own siblings and mother, all the way back through their ancestry.

Scarlet macaws in Mexico and Central America have five haplogroups -- genetically similar, but not identical mitochondrial DNA lines -- and each haplogroup has a number of haplotypes containing identical DNA lines. The researchers found that their scarlet macaws were all from haplogroup 6 and that 71 percent of the birds shared one of four unique haplotypes. They report the results of this analysis today (Aug 13) in the Proceedings of the National Academy of Sciences.

The researchers found that the probability of obtaining 14 birds from the wild and having them all come from the same haplogroup, one that is small and isolated, was extremely small. A better explanation, especially because these specimens ranged over a 300-year period, is that all the birds came from the same breeding population and that this population existed somewhere in the American Southwest or northern Mexico.

"These birds all likely came from the same source, but we don't have any way to support that assumption without examining the full genome," said George. "However, the genetic results likely indicate some type of narrow breeding from a small founder population with little or no introgression or resupply."

However, no one has found macaw breeding evidence dating to the 900 to 1200 period in the American Southwest or northern Mexico.

"The next step will be to analyze macaws from other archaeological sites in Arizona and northern Mexico to narrow down the location of this early breeding colony," said Douglas Kennett, professor and head of anthropology, Penn State, and co-director or the project.





Contacts and sources:
A'ndrea Elyse MesserPenn State

16 Going On 66: Will You Be the Same Person 50 Years from Now?



How much do you change between high school and retirement? The answer depends on whether you're comparing yourself to others or to your younger self.

The results of a new study, the first to test how personality might change over 50 years and relying on the same data source at both time points, finds that broad patterns of thoughts, feelings and behaviors - personality - do change, and this change appears to accumulate with time. But don't compare yourself to others; those who are the most emotionally stable when young are probably going to continue being the most stable as they age.

"The rankings (of personality traits) remain fairly consistent. People who are more conscientious than others their age at 16 are likely to be more conscientious than others at 66," said Rodica Damian, assistant professor of psychology at the University of Houston and lead author of a new study on the subject. "But, on average, everyone becomes more conscientious, more emotionally stable, and more agreeable.

University of Houston Psychologist Rodica Damian
Credit: University of Houston

Still, she said, researchers did find individual differences in change across time, with some people changing more than others and some changing in more maladaptive or harmful ways.

The work, "Sixteen Going on Sixty-Six: A Longitudinal Study of Personality Stability and Change across 50 Years," was published Aug. 16 in the Journal of Personality and Social Psychology.

Social scientists have long debated whether personality is stable - unchanged over time - or malleable. Recent studies have indicated it might be both, but longitudinal studies covering very long timespans and relying on the same data source at both time points are rare.

The new research supports the idea that personality is influenced by both genetics and environment.

Personality is described as patterns of thoughts, feelings and behaviors, consisting of five major traits: conscientiousness, agreeableness, openness to experiences, extraversion, and emotional stability. Damian said those five traits have been found across ages and cultures.

The combination of those traits - how dominant each trait is in a given individual relative to the other traits -makes up the personality profile.

With co-authors Marion Spengler of the University of Tuebingen in Germany, Brent W. Roberts of the University of Illinois at Urbana-Champaign, and Andreea Sutu, a graduate student working with Damian at UH, Damian used a dataset of U.S. high school students who answered a series of questions to assess personality in 1960 and again 50 years later.

Data from the Project Talent Personality Inventory allowed the researchers to answer several questions, including:

To what extent do people maintain their relative standing on personality traits compared with other people - for example, do people who are more impulsive than most of their peers at age 16 remain more impulsive than their peers at age 60?
  • To what extent do average levels of personality traits change? Are people, on average, more conscientious at 66 than at 16?
  • Does everyone change in the same way?
  • Are there gender differences in patterns of personality stability and change across time?
"Our findings suggest that personality has a stable component across the lifespan, both at the trait level and at the profile level, and that personality is also malleable and people mature as they age," the researchers wrote. They found gender differences in personality at any given time, Damian said, but, overall, men and women changed at the same rates across the lifespan.



Contacts and sources: 
Laurie Fickman
University of Houston

Saturday, August 18, 2018

New Matrix Delivers Healing Stem Cells to Injured Elderly Muscles



A car accident leaves an aging patient with severe muscle injuries that won’t heal. Treatment with muscle stem cells from a donor might restore damaged tissue, but doctors are unable to deliver them effectively. A new method may help change this.

Researchers at the Georgia Institute of Technology engineered a molecular matrix, a hydrogel, to deliver muscle stem cells called muscle satellite cells (MuSCs) directly to injured muscle tissue in patients whose muscles don’t regenerate well. In lab experiments on mice, the hydrogel successfully delivered MuSCs to injured, aged muscle tissue to boost the healing process while protecting the stem cells from harsh immune reactions.

The method was also successful in mice with a muscle tissue deficiency that emulated Duchene muscular dystrophy, and if research progresses, the new hydrogel therapy could one day save the lives of people suffering from the disease.

First author Woojin Han observes muscle tissue samples treated with the new MuSC nanohydrogel. 
Woojin Han observes muscle tissue in Young Jang's lab
Credit: Georgia Tech / Christopher Moore


Inflammatory war zone

Simply injecting additional muscle satellite cells into damaged, inflamed tissue has proven inefficient, in part because the stem cells encounter an immune system on the warpath.

“Any muscle injury is going to attract immune cells. Typically, this would help muscle stem cells repair damage. But in aged or dystrophic muscles, immune cells lead to the release a lot of toxic chemicals like cytokines and free radicals that kill the new stem cells,” said Young Jang, an assistant professor in Georgia Tech’s School of Biological Sciences and one of the study’s principal investigators.

Only between 1 and 20 percent of injected MuSCs make it to damaged tissue, and those that do, arrive there weakened. Also, some tissue damage makes any injection unfeasible, thus the need for new delivery strategies.

“Our new hydrogel protects the stem cells, which multiply and thrive inside the matrix. The gel is applied to injured muscle, and the cells engraft onto the tissues and help them heal,” said Woojin Han, a postdoctoral researcher in Georgia Tech’s School of Mechanical Engineering and the paper’s first author.

Han, Jang and Andres Garcia, the study’s other principal investigator, published their results on August 15, 2018, in the journal Science Advances. The National Institute of Arthritis and Musculoskeletal and Skin Diseases of the National Institutes of Health funded the research.
Hydrogel: watery nets

Hydrogels often start out as water-based solutions of molecular components that resemble crosses, and other components that make the ends of the crosses attach to each other. When the components come together, they fuse into molecular nets suspended in water, resulting in a material with the consistency of a gel.

If stem cells or a drug are mixed into the solution, when the net, or matrix, forms, it ensnares the treatment for delivery and protects the payload from death or dissipation in the body. Researchers can easily and reliably synthesize hydrogels and also custom-engineer them by tweaking their components, as the Georgia Tech researchers did in this hydrogel.

“It physically traps the muscle satellite cells in a net, but the cells also grab onto chemical latches we engineered into the net,” Han said.

This hydrogel’s added latches, which bond with proteins protruding from stem cells’ membranes, not only increase the cells’ adhesion to the net but also hinder them from committing suicide. Stem cells tend to kill themselves when they’re detached and free-floating.

The chemical components and the cells are mixed in solution then applied to the injured muscle, where the mixture sets to a matrix-gel patch that glues the stem cells in place. The gel is biocompatible and biodegradable.

“The stem cells keep multiplying and thriving in the gel after it is applied,” Jang said. “Then the hydrogel degrades and leaves behind the cells engrafted onto muscle tissue the way natural stem cells usually would be.”
Stem cell breakdown

In younger, healthier patients, muscle satellite cells are part of the natural healing mechanism.

“Muscle satellite cells are resident stem cells in your skeletal muscles. They live on muscle strands like specks, and they’re key players in making new muscle tissue,” Han said.

“As we age, we lose muscle mass, and the number of satellite cells also decreases. The ones that are left get weaker. It’s a double whammy,” Jang said. “At a very advanced age, a patient stops regenerating muscle altogether.”

“With this system we engineered, we think we can introduce donor cells to enhance the repair mechanism in injured older patients,” Han said. “We also want to get this to work in patients with Duchene muscular dystrophy.”

“Duchene muscular dystrophy is surprisingly frequent,” Jang said. “About 1 in 3,500 boys get it. They eventually get respiratory defects that lead to death, so we hope to be able to use this to rebuild their diaphragm muscles.”

If the method goes to clinical trials, researchers will likely have to work around the potential for donor cell rejection in human patients.

The following researchers coauthored the paper: Shannon Anderson, Mahir Mohiuddin, Shadi Nakhai, and Eunjung Shin from Georgia Tech; Isabel Freitas Amaral, and Ana Paula Pêgo from the University of Porto in Portugal, and Daniela Barros from Georgia Tech and the University of Porto. The research was funded by the National Institute of Arthritis and Musculoskeletal and Skin Diseases of the National Institutes of Health (awards # R21AR072287 and R01AR062368). Any opinions, findings and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect views of the National Institutes of Health.

 

Contacts and sources:
Ben Brumfield
Georgia Institute of Technology
Citation: Synthetic matrix enhances transplanted satellite cell engraftment in dystrophic and aged skeletal muscle with comorbid trauma.
Woojin M. Han, Shannon E. Anderson, Mahir Mohiuddin, Daniela Barros, Shadi A. Nakhai, Eunjung Shin, Isabel Freitas Amaral, Ana Paula Pêgo, Andrés J. García, Young C. Jang. Science Advances, 2018; 4 (8): eaar4008 DOI: 10.1126/sciadv.aar4008

World's First-Ever 4D Printing for Ceramics



A research team at City University of Hong Kong (CityU) has achieved a ground-breaking advancement in materials research by successfully developing the world's first-ever 4D printing for ceramics, which are mechanically robust and can have complex shapes. This could turn a new page in the structural application of ceramics.

Ceramic has a high melting point, so it is difficult to use conventional laser printing to make ceramics. The existing 3D-printed ceramic precursors, which are usually difficult to deform, also hinder the production of ceramics with complex shapes.

To overcome these challenges, the CityU team has developed a novel "ceramic ink", which is a mixture of polymers and ceramic nanoparticles. The 3D-printed ceramic precursors printed with this novel ink are soft and can be stretched three times beyond their initial length. These flexible and stretchable ceramic precursors allow complex shapes, such as origami folding. With proper heat treatment, ceramics with complex shapes can be made.


Printed ceramic origami mimicking the Sydney Opera House.


Credit: City University of Hong Kong

The team was led by Professor LU Jian, Vice-President (Research and Technology) and Chair Professor of Mechanical Engineering, who is a distinguished materials scientist with research interests ranging from fabricating nanomaterials and advanced structural materials to the computational simulation of surface engineering.

With the development of the elastic precursors, the research team has achieved one more breakthrough by developing two methods of 4D printing of ceramics.

4D printing is conventional 3D printing combined with the additional element of time as the fourth dimension, where the printed objects can re-shape or self-assemble themselves over time with external stimuli, such as mechanical force, temperature, or a magnetic field.

In this research, the team made use of the elastic energy stored in the stretched precursors for shape morphing. When the stretched ceramic precursors are released, they undergo self-reshaping. After heat treatment, the precursors turn into ceramics.

The resultant elastomer-derived ceramics are mechanically robust. They can have a high compressive strength-to-density ratio (547 MPa on 1.6 g cm-3 microlattice), and they can come in large sizes with high strength compared to other printed ceramics.

4D-printed ceramic Miura-ori

Credit: City University of Hong Kong

"The whole process sounds simple, but it's not," said Professor Lu. "From making the ink to developing the printing system, we tried many times and different methods. Like squeezing icing on a cake, there are a lot of factors that can affect the outcome, ranging from the type of cream and the size of the nozzle, to the speed and force of squeezing, and the temperature."

It took more than two and a half years for the team to overcome the limitations of the existing materials and to develop the whole 4D ceramic printing system.

In the first shaping method, a 3D-printed ceramic precursor and substrate were first printed with the novel ink. The substrate was stretched using a biaxial stretching device, and joints for connecting the precursor were printed on it. The precursor was then placed on the stretched substrate. With the computer-programmed control of time and the release of the stretched substrate, the materials morphed into the designed shape.

In the second method, the designed pattern was directly printed on the stretched ceramic precursor. It was then released under computer-programming control and underwent the self-morphing process.

The innovation was published in the latest issue of top academic journal Science Advances under the title "Origami and 4D printing of elastomer-derived ceramic structures". All research team members are from CityU, including Dr LIU Guo, Research Assistant, Dr ZHAO Yan, Senior Research Associate, and Dr WU Ge, Research Fellow.

"With the versatile shape-morphing capability of the printed ceramic precursors, its application can be huge!" said Professor Lu. One promising application will be for electronic devices. Ceramic materials have much better performance in transmitting electromagnetic signals than metallic materials. With the arrival of 5G networks, ceramic products will play a more important role in the manufacture of electronic products. The artistic nature of ceramics and their capability to form complex shapes also provide the potential for consumers to tailor-make uniquely designed ceramic mobile phone back plates.

Furthermore, this innovation can be applied in the aero industry and space exploration. "Since ceramic is a mechanically robust material that can tolerate high temperatures, the 4D-printed ceramic has high potential to be used as a propulsion component in the aerospace field," said Prof Lu.

Riding on the breakthrough in material and 4D-printing technique advancement, Prof Lu said the next step is to enhance the mechanical properties of the material, such as reducing its brittleness.

The research was supported by the Major Program of National Natural Science Foundation of China, the Hong Kong Collaborative Research Fund Scheme and Theme-based Research Scheme, the Innovation and Technology Commission via the Hong Kong Branch of National Precious Metals Material Engineering Research Center, the Guangdong Provincial Department of Science and Technology, and the Science and Technology Innovation Commission of Shenzhen Municipality.


Contacts and sources:
P.K. Lee
City University of Hong Kong (CityU)
Citation: 

Probiotic Use Link Between Brain Fogginess, Severe Bloating



Probiotic use can result in a significant accumulation of bacteria in the small intestine that can result in disorienting brain fogginess as well as rapid, significant belly bloating, investigators report.

In a published study of 38 patients, the 30 who reported problems like confusion and difficulty concentrating, in addition to their gas and bloating, were all taking probiotics, some several varieties.

When investigators looked further, they found large colonies of bacteria breeding in the patients’ small intestines, and high levels of D-lactic acid being produced by the bacteria lactobacillus’ fermentation of sugars in their food, says Dr. Satish S.C. Rao, director of neurogastroenterology/motility and the Digestive Health Clinical Research Center at the Medical College of Georgia at Augusta University.

Dr. Satish S.C. Rao, director of neurogastroenterology/motility and the Digestive Health Clinical Research Center at the Medical College of Georgia at Augusta University
Credit: Augusta University

D-lactic acid is known to be temporarily toxic to brain cells, interfering with cognition, thinking and sense of time. They found some patients had two to three times the normal amount of D-lactic acid in their blood. Some said their brain fogginess – which lasted from a half hour to many hours after eating – was so severe that they had to quit their jobs.

The report in the journal Clinical and Translational Gastroenterology appears to be the first time the connection has been made between brain fogginess, bacterial overgrowth in the small intestine, high levels of D-lactic acid in the gut and probiotic use, Rao says.

“What we now know is that probiotic bacteria have the unique capacity to break down sugar and produce D-lactic acid. So if you inadvertently colonize your small bowel with probiotic bacteria, then you have set the stage for potentially developing lactic acidosis and brain fogginess,” Rao says.

While probiotics can be beneficial in some scenarios, like helping a patient restore his gut bacteria after taking antibiotics, the investigators advised caution against its excessive and indiscriminate use.

“Probiotics should be treated as a drug, not as a food supplement,” Rao says, noting that many individuals self-prescribe the live bacteria, which are considered good for digestion and overall health.

Others have implicated probiotics in the production of D-lactic acid – and brain fogginess – in patients with a short bowel so their small intestine does not function properly, and in newborns fed formula containing the popular product. Short bowel syndrome results in a lot of undigested carbohydrates that are known to cause small intestinal bacterial overgrowth, or SIBO, and the high levels of D-lactic acid. Severe liver and kidney problems can produce similar problems.

Whether there was also a connection when the gut is intact was an unknown. “This is the first inroad,” says Rao.

All patients experiencing brain fogginess took probiotics and SIBO was more common in the brain fogginess group as well, 68 percent compared to 28 percent, respectively. Patients with brain fogginess also had a higher prevalence of D-lactic acidosis, 77 versus 25 percent, respectively.

When brain-foggy patients stopped taking probiotics and took a course of antibiotics, their brain fogginess resolved.

Movement of food through the gastrointestinal tract was slow in one third of the brain foggy patients and one fourth of the other group. Slower passage, as well as things like obesity surgery, can increase the chance of bacterial buildup, or SIBO.

“Now that we can identify the problem, we can treat it,” Rao says. Diagnosis includes breath, urine and blood tests to detect lactic acid, and an endoscopy that enables examination of fluid from the small intestines so the specific bacteria can be determined and the best antibiotics selected for treatment.

Normally there is not much D-lactic acid made in the small intestines, but probiotic use appears to change that. SIBO, which was present in most with brain fogginess, can cause bacteria to go into a feeding frenzy that ferments sugars resulting in production of uncomfortable things like hydrogen gas and methane that explain the bloating.

Probiotics added to that feeding frenzy the bacterium lactobacillus, which produces D-lactic acid as it breaks down sugars, The acid get absorbed in the blood and can reach the brain.

All those with brain fogginess, SIBO and/or D-lactic acidosis, were given antibiotics that targeted their bacterial population and asked to discontinue probiotics. Those without SIBO were asked to halt probiotics and stop eating yogurt, which is considered one of the best sources of probiotics. Those with SIBO and D-lactic acidosis but no brain fogginess also took antibiotics.

Following treatment, 70 percent of patients reported significant improvement in their symptoms and 85 percent said their brain fogginess was gone. Those without brain fogginess but with SIBO and high levels of D-lactic acid reported significant improvement in symptoms like bloating and cramping within three months.

Abdominal pain was the most common symptom in both groups and before treatment, six of those with brain fogginess reported a tremendous increase in their abdominal size within just a few minutes of eating.

All patients received extensive examination of their gastrointestinal tract, including a motility test, to rule out other potential causes of their symptoms. They filled out questionnaires about symptoms like abdominal pain, belching and gas and answered questions about related issues like antibiotic and probiotic use as well as food fads and yogurt consumption.

They were given carbohydrates followed by extensive metabolic testing looking at the impact on things like blood glucose and insulin levels. Levels of D-lactic acid and L-lactate acid, which results from our muscles’ use of glucose as energy and can cause muscle cramps, also were measured.

Probiotic use may be particularly problematic for patients who have known problems with motility, as well as those taking opioids and proton pump inhibitors, which reduce stomach acid secretion and so the natural destruction of excessive bacteria.

Probiotics are supposed to work in the colon and not the small intestines or stomach, Rao says, so motility issues can result in problems with probiotic bacteria reaching the proper place. A wide variety of problems, from conditions like diabetes to drugs like antidepressants and minerals like iron, can slow movement and increase the possibility that probiotics will remain too long in the upper gut where they can cause harm, he says.

Probiotics definitely can help, for example, people who have gastroenteritis, or stomach flu, or are left with diarrhea and other problems after antibiotics wipe out their natural gut bacteria, Rao says.

“In those situations, we want to build up their bacterial flora so probiotics are ideal,” he says.

Rao’s pursuit of a possible connection between probiotics, brain fogginess and bloating started with a memorable patient who developed significant amounts of both problems within a minute of eating.

“It happened right in front of our eyes,” Rao says of the dramatic abdominal distention. They knew the woman had diabetes, which can slow motility. When they looked in the blood and urine at a variety of metabolic compounds, they found the high levels of D-lactic acid and soon learned the patient used probiotics and regularly ate yogurt.

Next steps include additional studies in which the investigators better quantify and characterize the brain fogginess reported by patients and following patients for longer periods to ensure their problems remain resolved. Some patients in the current study required a couple of rounds of antibiotics, Rao notes.

Good food sources of probiotics include yogurt, sauerkraut, kimchi, kefir and dark chocolate, which are generally safe because of the small amounts of bacteria present, Rao says.

The 19-foot long small intestine has been a bit of an understudied organ, likely in part because it’s hard to visualize via the mouth or anus, Rao says. “I think the small bowel can be a source of huge mystery,” Rao says.

Your helpful gut bacteria, or microbiome, which are essential to things like a well-functioning immune system and general health, are largely in the large intestine and colon.




Contacts and sources:
Medical College of Georgia at Augusta University

Citation: Brain fogginess, gas and bloating: a link between SIBO, probiotics and metabolic acidosis.
Satish S. C. Rao, Abdul Rehman, Siegfried Yu, Nicole Martinez de Andino.Clinical and Translational Gastroenterology, 2018; 9 (6) DOI: 10.1038/s41424-018-0030-7

Friday, August 17, 2018

'Abrupt Thaw' Of Permafrost Beneath Lakes Could Significantly Affect Climate Change Models



Methane released by thawing permafrost from some Arctic lakes could significantly accelerate climate change, according to a new University of Alaska Fairbanks-led study.

The study, which was published Aug. 15 in the journal Nature Communications, focuses on the carbon released by thawing permafrost beneath thermokarst lakes. Such lakes develop when warming soil melts ground ice, causing the surface to collapse and form pools of water. Those pools accelerate permafrost thaw beneath the expanding lakes, providing food for microbes that produce the greenhouse gases carbon dioxide and methane.

Lead author Katey Walter Anthony and her colleagues studied hundreds of thermokarst lakes in Alaska and Siberia during a 12-year period, measuring their growth and how much methane was bubbling to their surface. By combining field work results with remote-sensing data of lake changes during the past two years, they determined the "abrupt thaw" beneath such lakes is likely to release large amounts of permafrost carbon into the atmosphere this century. The lake activity could potentially double the release from terrestrial landscapes by the 2050s.

The effort, conducted by a team of U.S. and German researchers, is part of a 10-year NASA-funded project to better understand climate change effects on the Arctic. Additional support by the National Science Foundation allowed scientists from UAF and the Alaska Division of Geological and Geophysical Surveys to collect data on permafrost location, thaw and associated greenhouse gas release from lakes in Interior Alaska's Goldstream Valley.

The researchers found the release of greenhouse gases beneath thermokarst lakes is relatively rapid, with deep thawing taking place over the course of decades. Permafrost in terrestrial environments generally experiences shallow seasonal thawing over longer time spans. The release of that surface permafrost soil carbon is often offset by an increased growth in vegetation.

"Thermokarst lakes provide a completely different scenario. When the lakes form, they flash-thaw these permafrost areas," said Walter Anthony, an associate professor with UAF's Water and Environmental Research Center. "Instead of centimeters of thaw, which is common for terrestrial environments, we've seen 15 meters of thaw beneath newly formed lakes in Goldstream Valley within the past 60 years."

Emissions from thermokarst lakes aren't currently factored into global climate models because their small size makes individual lakes difficult to include. However, the study's authors show that these lakes are hotspots of permafrost carbon release. They argue that not including them in global climate models overlooks their feedback effect, which occurs when the release of greenhouse gases from permafrost increases warming. That feedback is significant because methane is about 30 times more potent than carbon dioxide as a heat-trapping gas.

Existing models currently attribute about 20 percent of the permafrost carbon feedback this century to methane, with the rest due to carbon dioxide from terrestrial soils. By including thermokarst lakes, methane becomes the dominant driver, responsible for 70 to 80 percent of permafrost carbon-caused warming this century. Adding thermokarst methane to the models makes the feedback's effect similar to that of land-use change, which is the second-largest source of manmade warming.

Unlike shallow, gradual thawing of terrestrial permafrost, the abrupt thaw beneath thermokarst lakes is irreversible this century. Even climate models that project only moderate warming this century will have to factor in their emissions, according to the study.

"You can't stop the release of carbon from these lakes once they form," Walter Anthony said. "We cannot get around this source of warming."


Contacts and sources:\
Jeff Richardson
University of Alaska Fairbanks

Citation: 

Ancient Beetle Discovery Gives Clue To Gymnosperm Pollination

Plant-insect interactions, one of the critical bedrocks for modern ecosystems, are largely dominated by insect-angiosperm relationships owing to the hegemony enjoyed by flowering plants since the Late Cretaceous. Gymnosperm-insect interactions, on the other hand, are far less well understood, particularly in terms of pollination modes.

Insect-mediated pollination in gymnosperms and potentially prior to the rise of flowering plants is critical for understanding not only the complex biology of these plants today but also the ecology of pre-angiospermous ecosystems and the history of pollination specializations on gymnosperms.

A new mid-Cretaceous (99-million-year-old) boganiid beetle with specialized pollen feeding adaptations was reported in Current Biology on August 16, 2018. This discovery suggests an ancient origin for beetle pollination of cycads long before the rise of flowering plants.

Cycad pollen grains associated with C. cycadophilus

Credit: NIGPAS

Phylogenetic analyses of the beetle and associated pollen grains conducted by Dr. CAI Chenyang from the Nanjing Institute of Geology and Palaeontology of the Chinese Academy of Sciences (NIGPAS) and his colleagues indicated that it was probably a pollinator of early cycads.

Unlike modern wind-pollinated conifers and Ginkgo, cycads are unusual in that they are an ancient group of gymnosperms pollinated by insects, such as beetles and rarely thrips. Little is known about the early evolution of their pollination mode before the rise of angiosperms, or flowering plants, although cycads are well documented from the mid-Mesozoic.

The researchers discovered a new genus and species of boganiid beetle, named Cretoparacucujus cycadophilus Cai and Escalona, 2018, preserved with many tiny cycad pollen grains and possessing specialized mandibular patches for the transport of cycad pollen.

Most importantly, morphology-based phylogenetic placement of the species reveals it belongs to a clade of relict genera with a disjunct distribution encompassing southeastern Africa and southwestern Australia. The species are also specialist pollinators of the same clade of modern cycads. Thus, both morphological and phylogenetic evidence support the determination of the fossil as a cycad-associated insect species.

Ecological reconstruction of the mid-Cretaceous C. cycadophilus

Credit: NIGPAS

The fossil represents the earliest definitive fossil evidence for cycad-insect interactions, and illuminates the ancient history of the establishment of complex entomophily in cycads. It also indicates a probable ancient origin of beetle pollination of cycads at least in the early stage of the Jurassic, some 176 million years ago, long before flowering-plant dominance and the radiation of their pollinators such as bees and butterflies later in the Cretaceous.




Contacts and sources:
Chen Xiaozheng
Chinese Academy Of Sciences



Citation:  Beetle Pollination of Cycads in the Mesozoic
Chenyang Cai 10 Hermes E. Escalona Liqin Li Ziwei Yin Diying Huang Michael S. Engel
Published:August 16, 2018DOI :https://doi.org/10.1016/j.cub.2018.06.036
http://dx.doi.org/10.1016/j.cub.2018.06.036



Water-Worlds Are Common: Exoplanets May Contain Vast Amounts of Water

Scientists have shown that water is likely to be a major component of those exoplanets (planets orbiting other stars) which are between two to four times the size of Earth. It will have implications for the search of life in our Galaxy. The work is presented at the Goldschmidt conference in Boston.

The 1992 discovery of exoplanets orbiting other stars has sparked interest in understanding the composition of these planets to determine, among other goals, whether they are suitable for the development of life. Now a new evaluation of data from the exoplanet-hunting Kepler Space Telescope and the Gaia mission indicates that many of the known planets may contain as much as 50% water. This is much more than the Earth's 0.02% (by weight) water content.

"It was a huge surprise to realize that there must be so many water-worlds", said lead researcher Dr Li Zeng (Harvard University),

Exoplanets similar to Earth, artist concept
Credit: NASA

Scientists have found that many of the 4000 confirmed or candidate exoplanets discovered so far fall into two size categories: those with the planetary radius averaging around 1.5 that of the Earth, and those averaging around 2.5 times the radius of the Earth.

Now a group of International scientists, after analyzing the exoplanets with mass measurements and recent radius measurements from the Gaia satellite, have developed a model of their internal structure.

"We have looked at how mass relates to radius, and developed a model which might explain the relationship", said Li Zeng. The model indicates that those exoplanets which have a radius of around x1.5 Earth radius tend to be rocky planets (of typically x5 the mass of the Earth), while those with a radius of x2.5 Earth radius (with a mass around x10 that of the Earth) are probably water worlds".

"This is water, but not as commonly found here on Earth", said Li Zeng. "Their surface temperature is expected to be in the 200 to 500 degree Celsius range. Their surface may be shrouded in a water-vapor-dominated atmosphere, with a liquid water layer underneath. Moving deeper, one would expect to find this water transforms into high-pressure ices before we reaching the solid rocky core. The beauty of the model is that it explains just how composition relates to the known facts about these planets".

Li Zeng continued, "Our data indicate that about 35% of all known exoplanets which are bigger than Earth should be water-rich. These water worlds likely formed in similar ways to the giant planet cores (Jupiter, Saturn, Uranus, Neptune) which we find in our own solar system. The newly-launched TESS mission will find many more of them, with the help of ground-based spectroscopic follow-up. The next generation space telescope, the James Webb Space Telescope*, will hopefully characterize the atmosphere of some of them. This is an exciting time for those interested in these remote worlds".

Professor Sara Seager, Professor of Planetary Science at Massachusetts Institute of Technology, and deputy science director of the recently-launched TESS (Transiting Exoplanet Survey Satellite) mission, which will search for exoplanets, said:

"It's amazing to think that the enigmatic intermediate-size exoplanets could be water worlds with vast amounts of water. Hopefully atmosphere observations in the future--of thick steam atmospheres---can support or refute the new findings".

*JWST is the James Webb Space Telescope, which will be the successor to the Hubble space telescope. It is due to be launched in 2021, see https://www.bbc.com/news/science-environment-44631661 for background.


Contacts and sources:
Tom Parkhill
Goldschmidt 2018

Ants, Acorns and Climate Change


Case Western Reserve biologists study swift evolutionary changes in acorn-dwelling insects—and what it might mean for other species as climate warms

The relatively swift adaptability of tiny, acorn-dwelling ants to warmer environments could help scientists predict how other species might evolve in the crucible of global climate change.

That’s a big-picture conclusion from research into the some of the world’s smallest creatures, according to evolutionary biologists at Case Western Reserve University.

More specifically, the scientists are comparing the adaptability of a certain species of ant raised in the “heat-island” microclimate of three U.S. cities to those in nearby cooler rural areas.

“What we’re finding is the potential for ants—and other animals, perhaps—to evolve in response to anthropogenic (human-caused) climate change,” said lead researcher Sarah Diamond, who first began peering into acorns to study the ants in 2015. The research so far has shown that the ants adapt to a hotter world in only about 20 generations, or about 100 years.

This comparatively lightning-fast evolutionary response is adding to scientists’ understanding of evolutionary processes, in general, but also in understanding the effects of urbanization, said Diamond, the George B. Mayer Assistant Professor of Urban and Environmental Studies at the university.

“While we usually think of evolution as happening over thousands of years or more, we’re finding that it is happening more rapidly in these cases,” she said, “and that presents a unique opportunity to test the predictability and parallelism of evolutionary change.”

The most recent study by Diamond and Ryan Martin, an assistant professor of biology at Case Western Reserve, was published in July in the Proceedings of the Royal Society B, a broad-scope biology journal.

Earlier research by the Case Western Reserve researchers was featured in a New York Times reportand elsewhere and focused primarily on how “city ants and country ants” adapted in Cleveland and a nearby rural area.

The outcome of that earlier study was that ants from the city were more tolerant of heat than rural ants living in colonies about five degrees Fahrenheit cooler—an adaptation that would have arisen only over the last century as the city became urbanized and warmer due to the heat island effect.

A researcher works at one of the rural ant-collection sites used in the study.

Photo by Lacy Chick, Case Western Reserve University

Different cities, mixed results

The new paper describes how the research was extended to two more cities, Cincinnati, Ohio and Knoxville, Tennessee, to test whether the ants would respond in “parallel” to urban heat islands.

The scientists added the two new sites to test whether the outcomes would be consistent, or whether each area is distinctive, and because “cities function as easily replicated warming experiments across the globe” due to the urban heat island effect, Diamond said.

The measurements: Urban ants were again more tolerant to heat, but lost some of their tolerance to cold compared to their rural neighbors.

The researchers also found that urban ant populations produced more “sexual reproductives”—offspring who could, in turn, reproduce—under warmer laboratory rearing temperatures that mimicked their city habitats; rural populations produced fewer.

This new result suggests that the urban ants are indeed adapting to city life: “Their increased tolerance for warm temperatures is helping them live in cities,” Martin said.

Well, that was found to be true in Cleveland and Knoxville, but “Cincinnati is misbehaving,” Diamond said with a laugh, noting that the city ants there did not show the same degree of adaptability.

“Something is going on with that city and we need to figure out what that is,” she said. “But that’s not a bad thing. It’s actually super useful to know just how contingent or deterministic evolution is. We’ll keep looking and try to understand what’s going on.”



Contacts and sources:
Mike Scott
Case Western Reserve University

Citation: Evolution of thermal tolerance and its fitness consequences: parallel and non-parallel responses to urban heat islands across three cities
Sarah E. Diamond, Lacy D. Chick, Abe Perez, Stephanie A. Strickler, Ryan A. Martin. . Proceedings of the Royal Society B: Biological Sciences, 2018; 285 (1882): 20180036 DOI: 10.1098/rspb.2018.0036

Astronomers Observe Cosmic Steam Jets and Molecules Galore with ALMA’s Highest-Frequency Capabilities



A team of scientists using the highest-frequency capabilities of the Atacama Large Millimeter/submillimeter Array(ALMA) has uncovered jets

of warm water vapor streaming away from a newly forming star. The researchers also detected the “fingerprints” of an astonishing assortment of molecules near this stellar nursery.

The ALMA telescope in Chile has transformed how we see the universe, showing us otherwise invisible parts of the cosmos. This array of incredibly precise antennas studies a comparatively high-frequency sliver of radio light: waves that range from a few tenths of a millimeter to several millimeters in length. Recently, scientists pushed ALMA to its limits, harnessing the array’s highest-frequency (shortest wavelength) capabilities, which peer into a part of the electromagnetic spectrum that straddles the line between infrared light and radio waves.

Illustration highlighting ALMA's high-frequency observing capabilities.

Credit: NRAO/AUI/NSF, S. Dagnello

“High-frequency radio observations like these are normally not possible from the ground,” said Brett McGuire, a chemist at the National Radio Astronomy Observatory in Charlottesville, Virginia, and lead author on a paper appearing in the Astrophysical Journal Letters. “They require the extreme precision and sensitivity of ALMA, along with some of the driest and most stable atmospheric conditions that can be found on Earth.”

Under ideal atmospheric conditions, which occurred on the evening of 5 April 2018, astronomers trained ALMA’s highest-frequency, submillimeter vision on a curious region of the Cat’s Paw Nebula (also known as NGC 6334I), a star-forming complex located about 4,300 light-years from Earth in the direction of the southern constellation Scorpius.

Previous ALMA observations of this region at lower frequencies uncovered turbulent star formation, a highly dynamic environment, and a wealth of molecules inside the nebula.

Composite ALMA image of NGC 6334I, a star-forming region in the Cat's Paw Nebula, taken with the Band 10 receivers, ALMA's highest-frequency vision. The blue component is heavy water (HDO) streaming away from either a single protostar or a small cluster of protostars. The orange region is the "continuum emission" in the same region, which scientists found is extraordinarily rich in molecular fingerprints, including glycolaldehyde , the simplest sugar-related molecule.
.

Credit: ALMA (ESO/NAOJ/NRAO): NRAO/AUI/NSF, B. Saxton

To observe at higher frequencies, the ALMA antennas are designed to accommodate a series of “bands” — numbered 1 to 10 — that each study a particular sliver of the spectrum. The Band 10 receivers observe at the highest frequency (shortest wavelengths) of any of the ALMA instruments, covering wavelengths from 0.3 to 0.4 millimeters (787 to 950 gigahertz), which is also considered to be long-wavelength infrared light.

These first-of-their-kind ALMA observations with Band 10 produced two exciting results.

Jets of Steam from Protostar

One of ALMA’s first Band 10 results was also one of the most challenging, the direct observation of jets of water vapor streaming away from one of the massive protostars in the region. ALMA was able to detect the submillimeter-wavelength light naturally emitted by heavy water (water molecules made up of oxygen, hydrogen and deuterium atoms, which are hydrogen atoms with a proton and a neutron in their nucleus).

“Normally, we wouldn’t be able to directly see this particular signal at all from the ground,” said Crystal Brogan, an astronomer at the NRAO and co-author on the paper. “Earth’s atmosphere, even at remarkably arid places, still contains enough water vapor to completely overwhelm this signal from any cosmic source. During exceptionally pristine conditions in the high Atacama Desert, however, ALMA can in fact detect that signal. This is something no other telescope on Earth can achieve.”

ALMA Band 10 image of heavy water (HDO) streaming away from NGC 6334I in the Cat's Paw Nebula. This image is the result of ALMA's highest-frequency observing capabilities, which push the limits of ground-based astronomy.

Credit: ALMA (ESO/NAOJ/NRAO); NRAO/AUI/NSF, B. Saxton

As stars begin to form out of massive clouds of dust and gas, the material surrounding the star falls onto the mass at the center. A portion of this material, however, is propelled away from the growing protostar as a pair of jets, which carry away gas and molecules, including water.

The heavy water the researchers observed is flowing away from either a single protostar or a small cluster of protostars. These jets are oriented differently from what appear to be much larger and potentially more-mature jets emanating from the same region. The astronomers speculate that the heavy-water jets seen by ALMA are relatively recent features just beginning to move out into the surrounding nebula.

These observations also show that in the regions where this water is slamming into the surrounding gas, low-frequency water masers – naturally occurring microwave versions of lasers — flare up. The masers were detected in complementary observations by the National Science Foundation’s Very Large Array.

ALMA Observes Molecules Galore

In addition to making striking images of objects in space, ALMA is also a supremely sensitive cosmic chemical sensor. As molecules tumble and vibrate in space, they naturally emit light at specific wavelengths, which appear as spikes and dips on a spectrum. All of ALMA’s receiver bands can detect these unique spectral fingerprints, but those lines at the highest frequencies offer unique insight into lighter, important chemicals, like heavy water. They also provide the ability to see signals from complex, warm molecules, which have weaker spectral lines at lower frequencies.

Using Band 10, the researchers were able to observe a region of the spectrum that is extraordinarily rich in molecular fingerprints, including glycolaldehyde , the simplest sugar-related molecule.

When compared to previous best-in-the-world observations of the same source with the European Space Agency’s Herschel Space Observatory, the ALMA observations detected more than ten times as many spectral lines.

“We detected a wealth of complex organic molecules surrounding this massive star-forming region,” said McGuire. “These results have been received with excitement by the astronomical community and show once again how ALMA will reshape our understanding of the universe.”

ALMA is able to take advantage of these rare windows of opportunity when the atmospheric conditions are “just right” by using dynamic scheduling. That means, the telescope operators and astronomers carefully monitor the weather and conduct those planned observations that best fit the prevailing conditions.

“There certainly are quite a few conditions that have to be met to conduct a successful observation using Band 10,” concluded Brogan. “But these new ALMA results demonstrate just how important these observations can be.”

“To remain at the forefront of discovery, observatories must continuously innovate to drive the leading edge of what astronomy can accomplish,” said Joe Pesce, the program director for the National Radio Astronomy Observatory at NSF. “That is a core element of NSF’s NRAO, and its ALMA telescope, and this discovery pushes the limit of what is possible through ground-based astronomy.”

The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.




Contacts and sources:
Charles Blue
National Radio Astronomy Observatory
Citation: First Results of an ALMA Band 10 Spectral Line Survey of NGC 6334I: Detections of Glycolaldehyde (HC(O)CH2OH) and a New Compact Bipolar Outflow in HDO and CS.
Brett A. McGuire, Crystal L. Brogan, Todd R. Hunter, Anthony J. Remijan, Geoffrey A. Blake, Andrew M. Burkhardt, P. Brandon Carroll, Ewine F. van Dishoeck, Robin T. Garrod, Harold Linnartz, Christopher N. Shingledecker, Eric R. Willis.The Astrophysical Journal, 2018; 863 (2): L35 DOI: 10.3847/2041-8213/aad7bb

Smallest Transistor Worldwide Switches Current with a Single Atom in Solid Electrolyte


At Karlsruhe Institute of Technology (KIT), physicist Professor Thomas Schimmel and his team have developed a single-atom transistor, the smallest transistor worldwide. This quantum electronics component switches electrical current by controlled repositioning of a single atom, now also in the solid state in a gel electrolyte. The single-atom transistor works at room temperature and consumes very little energy, which opens up entirely new perspectives for information technology.

The single-atom transistor that works in a gel electrolyte reaches the limit of miniaturization. 
2018_097_Weltkleinster Transistor schaltet Strom mit einzelnem Atom in festem Elektrolyten_72dpi
Photo: Group of Professor Thomas Schimmel/KIT

The transistor is presented in Advanced Materials (DOI: 10.1002/adma.201801225). Digitization results in a high energy consumption. In industrialized countries, information technology presently has a share of more than 10% in total power consumption. The transistor is the central element of digital data processing in computing centers, PCs, smartphones, or in embedded systems for many applications from the washing machine to the airplane. A commercially available low-cost USB memory stick already contains several billion transistors.

In future, the singleatom transistor developed by Professor Thomas Schimmel and his  team at the Institute of Applied Physics (APH) of KIT might considerably enhance energy efficiency in information technology. “This quantum electronics element enables switching energies smaller than those of conventional silicon technologies by a factor of 10,000,” says physicist and nanotechnology expert Schimmel, who conducts research at the APH, the Institute of Nanotechnology (INT), and the Material Research Center for Energy Systems (MZE) of KIT. Earlier this year, Professor Schimmel, who is considered the pioneer of singleatom electronics, was appointed Co-Director of the Center for SingleAtom Electronics and Photonics established jointly by KIT and ETH Zurich.

In Advanced Materials, the KIT researchers present the transistor that reaches the limits of miniaturization. The scientists produced two minute metallic contacts. Between them, there is a gap as wide as a single metal atom. “By an electric control pulse, we position a single silver atom into this gap and close the circuit,” Professor Thomas Schimmel explains. “When the silver atom is removed again, the circuit is interrupted.”

The world’s smallest transistor switches current through the controlled reversible movement of a single atom. Contrary to conventional quantum electronics components, the single-atom transistor does not only work at extremely low temperatures near absolute zero, i.e. -273°C, but already at room temperature. This is a big advantage for future applications. The single-atom transistor is based on an entirely new technical approach. The transistor exclusively consists of metal, no semiconductors are used. This results in extremely low electric voltages and, hence, an extremely low energy consumption.

So far, KIT’s single atom transistor has applied a liquid electrolyte. Now, Thomas Schimmel and his team have designed a transistor that works in a solid electrolyte. The gel electrolyte produced by gelling an aqueous silver electrolyte with pyrogenic silicon dioxide combines the advantages of a solid with the electrochemical properties of a liquid. In this way, both safety and handling of the single-atom transistor are improved. 



Contacts and sources:
Monika Landgraf
Karlsruher Institut für Technologie (KIT)

Citation: Quasi-Solid-State Single-Atom Transistors.
Fangqing Xie, Andreas Peukert, Thorsten Bender, Christian Obermair, Florian Wertz, Philipp Schmieder, Thomas Schimmel. Advanced Materials, 2018; 30 (31): 1801225 DOI: 10.1002/adma.201801225  Abstract online at https://onlinelibrary.wiley.com/doi/full/10.1002/adma.201801225

Thursday, August 16, 2018

Microfossils May Be World's Oldest, Have Biological Characteristics

Scientists have confirmed that the 3.4 billion year old Strelley Pool microfossils had chemical characteristics similar to modern bacteria. This all but confirms their biological origin and ranks them amongst the world's oldest microfossils. The work is presented at the Goldschmidt geochemistry conference in Boston, with simultaneous publication in the peer-reviewed journal Geochemical Perspectives Letters (see below for reference).

A team of scientists, led by Dr Julien Alleon (IMPMC, Paris, France; and MIT, Cambridge, MA, USA) have been able to show that the chemical residuals from ancient microfossils match those of younger bacterial fossils, and so are likely to have been laid down by early life forms.

They compared the results of synchrotron-based X-ray absorption spectroscopy analysis of the Strelley Pool microfossils with more recent ones from the Gunflint Formation (1.9 billion years old, found on the shores of Lake Superior, Ontario, Canada) and with modern bacteria. All showed similar absorption features, indicating that the residual chemicals were made from the same building blocks, thereby supporting a biological origin (see illustration below).

The image shows (left) an electron microscope image of a microfossil form Strelley Pool. On the right we see the pattern of X-ray absorption for Strelley Pool, Gunflint, and modern microorganisms, with distinctive peaks indicating the presence of various molecular functional groups (including 285.1 eV for aromatic/olefinic groups, 286.7 eV for imine/nitrile/carbonyl/phenol groups, 288.2 eV for amide groups, 288.6 eV for carboxyl/ester/acetal groups, 289.4 eV for hydroxyl groups).

Credit: Julian Alleon/GPL

Dr Jullien Alleon said: "There are a couple of important points which come out of this work. Firstly, we demonstrate that the elemental and molecular characteristics of these 3.4 Ga microfossils are consistent with biological remains, slightly degraded by fossilization processes. This effectively supports the biological origin of the Strelley Pool microfossils. There are competing claims over which microfossils are actually the world's oldest, this analytical strategy needs to be applied to other ancient samples to help settle the controversy.

Secondly, it is remarkable that these echoes of past life have survived the extreme conditions they have experienced over the last 3.4 billion years: we know from the molecular structure of the microfossils that they have been exposed to temperatures of up to 300 °C for long periods. And yet we are still able to see signs of their original chemistry.

This is a step forward to confirming that these are indeed the oldest fossils yet discovered."

Commenting, Professor Vickie Bennett (Australian National University) said: "This is exciting work with the new types of analyses providing compelling evidence that the cherts contain biogenic microfossils. This is in line with other observations for early life from the Strelley Pool rocks, including stromatolites interpreted as microbial mats, and further confirming that the minimum age for life on Earth is 3.4 billion years.

The techniques used here are not applicable to the older rocks that host the claims for the oldest terrestrial life, as these rocks were exposed to much higher temperatures. These samples include the 3.7 billion year old stromatolites from Isua, Greenland and the 4.1 billion year old Canadian microfossils. However, this work shows how quickly the field is developing and that new capabilities for testing and confirming earlier evidence of life are in reach".

There is some evidence that life may have developed earlier, perhaps around 4.1 bn years

This work is simultaneously published in the peer-reviewed journal Geochemical Perspectives Letters,


Contacts and sources:
Tom Parkhill
Goldschmidt Conference

Citation: The Strelley Pool fossils were discovered in 2013 in Western Australia. They are probably simple prokaryote bacteria, i.e. without a cell nucleus or other sub-cellular bodies https://www.sciencedirect.com/science/article/pii/S0301926812002823

Alleon J., Bernard S., Le Guillou C., Beyssac O., Sugitani K. & Robert F. Chemical nature of the 3.4 Ga Strelley Pool microfossils. Geochemical Perspectives Letters 7, 37-42, 2018 - doi: 10.7185/geochemlet.1817. https://www.geochemicalperspectivesletters.org/

Breakthrough May Lead to Sea Change in Desalination Technology

More than 300 million people around the world rely on desalinated water for part or all of their daily needs — a demand that will only grow with larger populations and improved standards of living.

Accessing the oceans for drinking water, however, requires desalination technologies that are complicated and expensive.

In the current issue of Science, researchers at the University of Connecticut offer a new approach to manufacturing a key facet of the process — the membranes integral to desalination. Using an additive manufacturing approach that employs electrospraying, UConn scientists were able to create ultra-thin, ultra-smooth polyamide membranes that are less prone to fouling and may require less power to move water through them.

The most commonly used technology for desalination is reverse osmosis, a process in which seawater is forced through a membrane capable of removing salts and many other molecule contaminants. Conventional approaches to making reverse osmosis membranes have not changed in nearly 40 years.

“Today’s membranes for reverse osmosis are not made in a way that allows their properties to be controlled,” says Jeffrey McCutcheon, study author and UConn School of Engineering’s Al Geib Professor of Environmental Engineering Research and Education. “Our approach uses an ‘additive’ technique that allows for control of a membrane’s fundamental properties such as thickness and roughness, which is currently impossible using conventional methods.”

While the use of reverse osmosis continues to rise around the world, many of its drawbacks, which include high energy consumption and a propensity for membranes to foul, continue to plague the industry.

Illustration depicting the process of reverse osmosis. 

Credit:  iStock/Getty Images Plus

The traditional approach to making these membranes is known as interfacial polymerization. This method relies on a self-terminating reaction between an aqueous phase amine and an organic phase acid chloride monomer. The resulting polyamide films — exceedingly thin, highly selective, and permeable to water — became the gold standard membrane for reverse osmosis.

However, as the field has advanced, the need to better control this reaction to allow for membranes of varying thickness and roughness to optimize water flow and reduce fouling has become more pressing.

UConn’s method provides a superior level of control over the thickness and roughness of the polyamide membrane, says McCutcheon.

Typical polyamide membranes have a thickness between 100 and 200 nanometers (nm) that cannot be controlled. UConn’s electrospray method allows for the controlled creation of membranes as thin as 15 nm and the capacity to control membrane thickness in 4 nm increments, a level of specificity not seen before in this area. Likewise, typical RO membranes have a roughness of over 80 nm. UConn researchers were able to create membranes with roughness as low as 2 nm.

“Our printing approach to making polyamide membranes has the additional benefit of being scalable,” McCutcheon says. “Much like electrospinning has seen dramatic improvements in roll-to-roll processing, electrospraying can be scaled with relative ease.”

The authors also say this type of manufacturing could save on chemical consumption as traditional chemical baths are not needed as part of the membrane fabrication process.

“In the lab, we use 95 percent less chemical volume making membranes by printing when compared to conventional interfacial polymerization,” says McCutcheon. “These benefits would be magnified in large-scale membrane manufacturing and make the process more ‘green’ than it has been for the past 40 years.”

This innovative new approach is not limited to desalination and could lead to better membranes for other separation processes, says McCutcheon, who also serves as the executive director of the Fraunhofer USA Center for Energy Innovation at UConn, which develops new applied membrane technologies. “In fact, we hope that this method will enable new materials to be considered for a myriad of membrane separation processes, perhaps in processes where those materials were not, or could not, be used before.”

In addition to McCutcheon, the study authors included Maqsud Chowdhury, a recent Ph.D. graduate in chemical engineering, and the paper’s lead author; James Steffes, a current Ph.D. student, and Bryan Huey, professor of materials science and engineering.

The team has filed a patent application for the technology and is currently working with UConn’s Technology Commercialization Services to explore commercialization options. The team also received an award from the UConn SPARK Technology Commercialization Fund.

The research was supported by a grant from the U.S. Environmental Protection Agency #RD834872, The General Electric Graduate Fellowship for Innovation, the National Science Foundation DMR:MRI Award # 1726862, and the University of Connecticut Academic Plan funding program, and the Department of Chemical and Biomolecular Engineering and Center for Environmental Sciences and Engineering.





Contacts and sources:
Colin Poitras
University of Connecticut


Citation: 3D printed polyamide membranes for desalination.
Maqsud R. Chowdhury, James Steffes, Bryan D. Huey, Jeffrey R. Mccutcheon. Science, 2018 DOI: 10.1126/science.aar2122

Gold and Platinum Make Most Wear-Resistant Metal Alloy in The World



If you’re ever unlucky enough to have a car with metal tires, you might consider a set made from a new alloy engineered at Sandia National Laboratories. You could skid — not drive, skid — around the Earth’s equator 500 times before wearing out the tread.

Sandia’s materials science team has engineered a platinum-gold alloy believed to be the most wear-resistant metal in the world. It’s 100 times more durable than high-strength steel, making it the first alloy, or combination of metals, in the same class as diamond and sapphire, nature’s most wear-resistant materials. Sandia’s team recently reported their findings in Advanced Materials. “We showed there’s a fundamental change you can make to some alloys that will impart this tremendous increase in performance over a broad range of real, practical metals,” said materials scientist Nic Argibay, an author on the paper.

Sandia National Laboratories researchers Michael Chandross, left, and Nic Argibay show a computer simulation used to predict the unprecedented wear resistance of their platinum-gold alloy, and an environmental tribometer used to demonstrate it.


Photo by Randy Montoya

Although metals are typically thought of as strong, when they repeatedly rub against other metals, like in an engine, they wear down, deform and corrode unless they have a protective barrier, like additives in motor oil.

In electronics, moving metal-to-metal contacts receive similar protections with outer layers of gold or other precious metal alloys. But these coatings are expensive. And eventually they wear out, too, as connections press and slide across each other day after day, year after year, sometimes millions, even billions of times. These effects are exacerbated the smaller the connections are, because the less material you start with, the less wear and tear a connection can endure before it no longer works.

With Sandia’s platinum-gold coating, only a single layer of atoms would be lost after a mile of skidding on the hypothetical tires. The ultradurable coating could save the electronics industry more than $100 million a year in materials alone, Argibay says, and make electronics of all sizes and across many industries more cost-effective, long-lasting and dependable — from aerospace systems and wind turbines to microelectronics for cell phones and radar systems.

“These wear-resistant materials could potentially provide reliability benefits for a range of devices we have explored,” said Chris Nordquist, a Sandia engineer not involved in the study. “The opportunities for integration and improvement would be device-specific, but this material would provide another tool for addressing current reliability limitations of metal microelectronic components.”

New metal puts an old theory to rest

You might be wondering how metallurgists for thousands of years somehow missed this. In truth, the combination of 90 percent platinum with 10 percent gold isn’t new at all.

But the engineering is new. Argibay and coauthor Michael Chandross masterminded the design and the new 21st century wisdom behind it. Conventional wisdom says a metal’s ability to withstand friction is based on how hard it is. The Sandia team proposed a new theory that says wear is related to how metals react to heat, not their hardness, and they handpicked metals, proportions and a fabrication process that could prove their theory.

“Many traditional alloys were developed to increase the strength of a material by reducing grain size,” said John Curry, a postdoctoral appointee at Sandia and first author on the paper. “Even still, in the presence of extreme stresses and temperatures many alloys will coarsen or soften, especially under fatigue. We saw that with our platinum-gold alloy the mechanical and thermal stability is excellent, and we did not see much change to the microstructure over immensely long periods of cyclic stress during sliding.”

Now they have proof they can hold in their hands. It looks and feels like ordinary platinum, silver-white and a little heavier than pure gold. Most important, it’s no harder than other platinum-gold alloys, but it’s much better at resisting heat and a hundred times more wear resistant.

The team’s approach is a modern one that depended on computational tools. Argibay and Chandross’ theory arose from simulations that calculated how individual atoms were affecting the large-scale properties of a material, a connection that’s rarely obvious from observations alone. Researchers in many scientific fields use computational tools to take much of the guesswork out of research and development.

“We’re getting down to fundamental atomic mechanisms and microstructure and tying all these things together to understand why you get good performance or why you get bad performance, and then engineering an alloy that gives you good performance,” Chandross said.

A slick surprise

Still, there will always be surprises in science. In a separate paper published in Carbon, the Sandia team describes the results of a remarkable accident. One day, while measuring wear on their platinum-gold, an unexpected black film started forming on top. They recognized it: diamond-like carbon, one of the world’s best man-made coatings, slick as graphite and hard as diamond. Their creation was making its own lubricant, and a good one at that.

Diamond-like carbon usually requires special conditions to manufacture, and yet the alloy synthesized it spontaneously.

“We believe the stability and inherent resistance to wear allows carbon-containing molecules from the environment to stick and degrade during sliding to ultimately form diamond-like carbon,” Curry said. “Industry has other methods of doing this, but they typically involve vacuum chambers with high temperature plasmas of carbon species. It can get very expensive.”

The phenomenon could be harnessed to further enhance the already impressive performance of the metal, and it could also potentially lead to a simpler, more cost-effective way to mass-produce premium lubricant.





Contacts and sources:
Troy RummlerSandia National Laboratories



Citation: Achieving Ultralow Wear with Stable Nanocrystalline Metals.
John F. Curry, Tomas F. Babuska, Timothy A. Furnish, Ping Lu, David P. Adams, Andrew B. Kustas, Brendan L. Nation, Michael T. Dugger, Michael Chandross, Blythe G. Clark, Brad L. Boyce, Christopher A. Schuh, Nicolas Argibay.Advanced Materials, 2018; 30 (32): 1802026 DOI: 10.1002/adma.201802026

That Stinks! One American in 15 Smells Odors That Aren’t There


Imagine the foul smell of an ash tray or burning hair. Now imagine if these kinds of smells were present in your life, but without a source. A new study finds that 1 in 15 Americans (or 6.5 percent) over the age of 40 experiences phantom odors. 

The study, published in JAMA Otolaryngology-Head and Neck Surgery(link is external), is the first in the U.S. to use nationally representative data to examine the prevalence of and risk factors for phantom odor perception. The study could inform future research aiming to unlock the mysteries of phantom odors.

This is the first study in the U.S. to use nationally representative survey data to examine the prevalence of and risk factors for phantom odor perception.

Credit: NIH

The study was led by Kathleen Bainbridge, Ph.D., of the Epidemiology and Biostatistics Program at the National Institute on Deafness and Other Communication Disorders (NIDCD), part of the National Institutes of Health. Bainbridge and her team used data from 7,417 participants over 40 years of age from the 2011-2014 National Health and Nutrition Examination Survey (NHANES). The NHANES data were collected by the National Center for Health Statistics, which is part of the Centers for Disease Control and Prevention; data collection was partly funded by the NIDCD.

“Problems with the sense of smell are often overlooked, despite their importance. They can have a big impact on appetite, food preferences, and the ability to smell danger signals such as fire, gas leaks, and spoiled food,” said Judith A. Cooper, Ph.D., acting director of the NIDCD.

Donald Leopold, M.D., one of the study’s authors and clinical professor in the Department of Surgery at University of Vermont Medical Center, Burlington, adds that patients who perceive strong phantom odors often have a miserable quality of life, and sometimes cannot maintain a healthy weight.

Researchers used this NHANES survey question to determine whether participants had experienced phantom odor perception: “Do you sometimes smell an unpleasant, bad, or burning odor when nothing is there?” To explore the correlation between phantom odors and participant characteristics, the researchers looked at participants’ age, sex, education level, race/ethnicity, socio-economic status, certain health habits, and general health status.

The ability to identify odors tends to decrease with age. Phantom odor perception, on the other hand, seems to improve with age. One previous study, using data from a community in Sweden, showed that 4.9 percent of people over the age of 60 experience phantom odors, with a higher prevalence in women than men. The present study found a similar prevalence in the over-60 age group, but in examining a broader age range, found an even higher prevalence in ages 40-60. The study also found that about twice as many women as men reported phantom odors, and that the female predominance was particularly striking for those under age 60.

Other risk factors for the onset of phantom odors include head injury, dry mouth, poor overall health, and low socio-economic status. Researchers hypothesized that people with lower socio-economic status may more commonly be exposed to environmental pollutants and toxins, or have health conditions that contribute to phantom odors, either directly or because of medications needed to treat their health conditions.

“The causes of phantom odor perception are not understood. The condition could be related to overactive odor-sensing cells in the nasal cavity or perhaps a malfunction in the part of the brain that understands odor signals. A good first step in understanding any medical condition is a clear description of the phenomenon. From there, other researchers may form ideas about where to look further for possible causes and ultimately for ways to prevent or treat the condition,” said Bainbridge.





Contacts and sources:
NIH/National Institute on Deafness and Other Communication Disorders


Citation: Factors Associated With Phantom Odor Perception Among US AdultsFindings From the National Health and Nutrition Examination Survey
Kathleen E. Bainbridge, Danita Byrd-Clark, Donald Leopold. . JAMA Otolaryngology-Head and Neck Surgery, 2018 DOI: 10.1001/jamaoto.2018.1446

Printable Metal Tags Turn Ordinary Things into Smart Objects


Engineers have developed printable metal tags that could be attached to everyday objects and turn them into “smart” Internet of Things devices.

The metal tags are made from patterns of copper foil printed onto thin, flexible, paper-like substrates and are made to reflect WiFi signals. The tags work essentially like “mirrors” that reflect radio signals from a WiFi router. When a user’s finger touches these mirrors, it disturbs the reflected WiFi signals in such a way that can be remotely sensed by a WiFi receiver, like a smartphone.

The tags can be tacked onto plain objects that people touch and interact with every day, like water bottles, walls or doors. These plain objects then essentially become smart, connected devices that can signal a WiFi device whenever a user interacts with them. The tags can also be fashioned into thin keypads or smart home control panels that can be used to remotely operate WiFi-connected speakers, smart lights and other Internet of Things appliances.

Printed thin, flexible LiveTag tags in comparison with a piece of photo paper (far left).
LiveTag metal tags
Photos courtesy of Xinyu Zhang

“Our vision is to expand the Internet of Things to go beyond just connecting smartphones, smartwatches and other high-end devices,” said senior author Xinyu Zhang, a professor of electrical and computer engineering at the UC San Diego Jacobs School of Engineering and member of the Center for Wireless Communications at UC San Diego. “We’re developing low-cost, battery-free, chipless, printable sensors that can include everyday objects as part of the Internet of Things.”

Zhang’s team named the technology “LiveTag.” These metal tags are designed to only reflect specific signals within in the WiFi frequency range. By changing the type of material they’re made of and the pattern in which they’re printed, the researchers can redesign the tags to reflect either Bluetooth, LTE or cellular signals.

The tags have no batteries, silicon chips, or any discrete electronic components, so they require hardly any maintenance—no batteries to change, no circuits to fix.

The team presented their work at the recent USENIX Symposium on Networked Systems Design and Implementation Conference.

Smart tagging

LiveTag music player controller

Photos courtesy of Xinyu Zhang


As a proof of concept, the researchers used LiveTag to create a paper-thin music player controller complete with a play/pause button, next track button and sliding bar for tuning volume. The buttons and sliding bar each consist of at least one metal tag so touching any of them sends signals to a WiFi device. The researchers have so far only tested the LiveTag music player controller to remotely trigger a WiFi receiver, but they envision that it would be able to remotely control WiFi-connected music players or speakers when attached to a wall, couch armrest, clothes, or other ordinary surface.

The researchers also adapted LiveTag as a hydration monitor. They attached it to a plastic water bottle and showed that it could be used to track a user’s water intake by monitoring the water level in the bottle. The water inside affects the tag’s response in the same way a finger touch would—as long as the bottle is not made of metal, which would block the signal. The tag has multiple resonators that each get detuned at a specific water level. The researchers imagine that the tag could be used to deliver reminders to a user’s smartphone to prevent dehydration.

Future applications

On a broader scope, Zhang envisions using LiveTag technology to track human interaction with everyday objects. For example, LiveTag could potentially be used as an inexpensive way to assess the recovery of patients who have suffered from stroke.

“When patients return home, they could use this technology to provide data on their motor activity based on how they interact with everyday objects at home—whether they are opening or closing doors in a normal way, or if they are able to pick up bottles of water, for example. The amount, intensity and frequency of their activities could be logged and sent to their doctors to evaluate their recovery,” said Zhang. “And this can all be done in the comfort of their own homes rather than having to keep going back to the clinic for frequent motor activity testing,” he added.

Another example is tagging products at retail stores and assessing customer interest based on which products they touch. Rather than use cameras, stores could use LiveTag as an alternative that offers customers more privacy, said Zhang.

Next steps

The researchers note several limitations of the technology. LiveTag currently cannot work with a WiFi receiver further than one meter (three feet) away, so researchers are working on improving the tag sensitivity and detection range. Ultimately, the team aims to develop a way to make the tags using normal paper and ink printing, which would make them cheaper to mass produce.




Contacts and sources:
Liezel Labios
University of California - San Diego

Citation:  “LiveTag: Sensing Human-Object Interaction Through Passive Chipless WiFi Tags.” Co-authors include Chuhan Gao and Yilong Li at University of Wisconsin-Madison.

Wearable 'Microbrewery' Saves Human Body from Radiation Damage


The same way that yeast yields beer and bread can help hospital lab workers better track their daily radiation exposure, enabling a faster assessment of tissue damage that could lead to cancer.

But rather than building portable cellars or ovens, Purdue University researchers have engineered yeast "microbreweries" within disposable badges made of freezer paper, aluminum and tape. Simply adding a drop of water activates the yeast to show radiation exposure as read by an electronic device.


Credit: Purdue University Watch a YouTube video at
On a commercial level, the readout device could one day be a tablet or phone. The badge could also be adapted in the future for nuclear power plant workers and victims of nuclear disasters.

"You would use the badge when you're in the lab and recycle it after you've checked your exposure by plugging it into a device," said Manuel Ochoa, a postdoctoral researcher in Purdue's School of Electrical and Computer Engineering

A team of Purdue researchers, including Rahim Rahimi (left) and Manuel Ochoa (right), proposes using yeast fermentation to more quickly detect biological radiation damage.
Credit:  Purdue University image/Kayla Wiles

Radiology workers are regularly exposed to low doses of radiation when they obtain patient imagery, such as X-rays. While protective gear largely keeps workers within a safe range of radiation exposure, absorbing a little bit is still inevitable.

Radiation doses creeping above regulated guidelines pose risk for developing conditions such as cancer, cataracts, skin irritation or thyroid disease.

"Currently, radiology workers are required to wear badges, called dosimeters, on various parts of their bodies for monitoring their radiation exposure," said Babak Ziaie, Purdue professor of electrical and computer engineering. "They wear the badges for a month or two, and then they send them to the company that made them. But it takes weeks for the company to read the data and send a report back to the hospital. Ours give an instant reading at much lower cost."

Workers in hospitals and nuclear facilities can wear disposable yeast badges to check their daily radiation exposure instantly.
Credit: Purdue University image/Kayla Wiles

The success of the badge lies in the quick and measurable response of yeast to radiation: The higher the radiation dose, the higher the percentage of yeast cells that die. Wetting the badge activates the cells that are still alive to eat glucose and release carbon dioxide – the same fermentation process responsible for brewing beer and making bread rise.

When carbon dioxide bubbles at the surface, ions also form. The concentration of these ions increases the electrical conductivity of yeast, which can be measured by hooking up the badge to a readout system.

"We use the change in electrical properties of the yeast to tell us how much radiation damage it incurred. A slow decrease in electrical conductivity over time indicates more damage," said Rahim Rahimi, Purdue postdoctoral researcher in electrical and computer engineering.

Numbers from the readout system translate to rads – the units used by entities like the Occupational Safety and Health Administration to specify limits on how much radiation human tissue can safely absorb. Skin of the whole body, for example, shouldn't be exposed to more than 7.5 rad over a three month period.

Simply adding a drop of water to a badge engineered by Purdue researchers activates yeast to show radiation exposure as read by an electronic device.
Credit:  Purdue University image/Kayla Wiles

The researchers could detect a radiation dose as little as 1 millirad in the yeast badges, which is comparable to current commercial badges.

Yeast also is known to be genetically similar to human tissue. Data from the badges can, therefore, inform future work on how radiation damage happens to human DNA and proteins.

"For yeast, it seems that radiation primarily affects the cell walls of the membrane and mitochondria," Ochoa said. "Since biologists are already familiar with yeast, then we're more likely to understand what's causing the biological effects of radiation in organic matter."

Published findings appear in the journal Advanced Biosystems. A patent is pending for this technology via the Purdue Research Foundation. The research was partly funded by NextFlex under AFRL Cooperative Agreement No. FA8650-15-2-5401.

 


Contacts and sources:
 Kayla Wiles, Babak Ziaie, Manuel Ochoa, Rahim Rahimi
Purdue University

Citation: Yeast metabolic  response as an indicator of radiation damage in biological tissue
Chang Keun Yoon, Manuel Ochoa, Albert Kim, Rahim Rahimi, Jiawei Zhou and Babak Ziaie
Purdue University, West Lafayette, IN, USA
doi: 10.1002/adbi.201800126