A new approach to reducing bulging tummy fats has shown promise in laboratory trials

Date:
December 28, 2017

Source:
Nanyang Technological University

Summary:
A new approach to reducing bulging tummy fats has shown promise in laboratory trials. It combines a new way to deliver drugs, via a micro-needle patch, with drugs that are known to turn energy-storing white fat into energy-burning brown fat.

 

Prof Chen Peng (left) holding the new microneedle fat burning patch with Asst Prof Xu Chenjie.
Credit: NTU Singapore

 

 

A new approach to reducing bulging tummy fats has shown promise in laboratory trials.

It combines a new way to deliver drugs, via a micro-needle patch, with drugs that are known to turn energy-storing white fat into energy-burning brown fat. This innovative approach developed by scientists from Nanyang Technological University, Singapore (NTU Singapore) reduced weight gain in mice on a high fat diet and their fat mass by more than 30 per cent over four weeks.

The new type of skin patch contains hundreds of micro-needles, each thinner than a human hair, which are loaded with the drug Beta-3 adrenergic receptor agonist or another drug called thyroid hormone T3 triiodothyronine.

When the patch is pressed into the skin for about two minutes, these micro-needles become embedded in the skin and detach from the patch, which can then be removed.

As the needles degrade, the drug molecules then slowly diffuse to the energy-storing white fat underneath the skin layer, turning them into energy-burning brown fats.

Brown fats are found in babies and they help to keep the baby warm by burning energy. As humans grow older, the amount of brown fats lessens and is replaced with visceral white fats.

Published in the journal Small Methods recently by NTU Professor Chen Peng and Assistant Professor Xu Chenjie, this approach could help to address the worldwide obesity problem without resorting to surgical operations or oral medication which could require large dosages and could have serious side effects.

“With the embedded microneedles in the skin of the mice, the surrounding fats started browning in five days, which helped to increase the energy expenditure of the mice, leading to a reduction in body fat gain,” said Asst Prof Xu, who focuses on research in drug delivery systems.

“The amount of drugs we used in the patch is much less than those used in oral medication or an injected dose. This lowers the drug ingredient costs while our slow-release design minimises its side effects,” said Asst Prof Xu.

Obesity which results from an excessive accumulation of fat is a major health risk factor for various diseases, including heart disease, stroke and type-2 diabetes. The World Health Organisation estimates that 1.9 billion adults in the world are overweight in 2016 with 650 million of them being obese.

“What we aim to develop is a painless patch that everyone could use easily, is unobtrusive and yet affordable,” said Prof Chen, a biotechnology expert who researches on obesity. “Most importantly, our solution aims to use a person’s own body fats to burn more energy, which is a natural process in babies.”

Under the two scientists’ guidance at NTU’s School of Chemical and Biomedical Engineering, research fellow Dr Aung Than conducted experiments which showed that the patch could suppress weight gain in mice that were fed a high fat diet and reduce their fat mass by over 30 per cent, over a period of four weeks.

The treated mice also had significantly lower blood cholesterol and fatty acids levels compared to the untreated mice.

Being able to deliver the drug directly to the site of action is a major reason why it is less likely to have side effects than orally delivered medication.

The team estimates that their prototype patch had a material cost of about S$5 (US$3.50) to make, which contains beta-3 adrenergic receptor agonist combined with Hyaluronic acid, a substance naturally found in the human body and commonly used in products like skin moisturisers.

Beta-3 adrenergic receptor agonist is a drug approved by the Federal Drug Administration of the United States and is used to treat overactive bladders, while T3 triiodothyronine is a thyroid hormone commonly used for medication for an underactive thyroid gland.

Both have been shown in other research studies to be able to turn white fats brown, but their use in reducing weight gain is hampered by potentially serious side-effects and drug accumulation in non-targeted tissues if conventional drug delivery routes were used, such as through oral intake.

NTU’s Lee Kong Chian School of Medicine Associate Professor Melvin Leow, who was not affiliated with this study, said it is exciting to be able to tackle obesity via the browning of white fat, and the results were promising.

“These data should encourage Phase I Clinical studies in humans to translate these basic science findings to the bedside, with the hope that these microneedle patches may be developed into an established cost-effective modality for the prevention or treatment of obesity in the near future,” added Assoc Prof Leow, an endocrinologist.

Since the publication of the paper, the team has received keen interest from biotechnology companies and is looking to partner clinician scientists to further their research.

Story Source:

Materials provided by Nanyang Technological UniversityNote: Content may be edited for style and length.


Journal Reference:

  1. Aung Than, Ke Liang, Shaohai Xu, Lei Sun, Hongwei Duan, Fengna Xi, Chenjie Xu, Peng Chen. Transdermal Delivery of Anti-Obesity Compounds to Subcutaneous Adipose Tissue with Polymeric Microneedle PatchesSmall Methods, 2017; 1 (11): 1700269 DOI: 10.1002/smtd.201700269

Researchers refine method of making bio-ink droplets stick to each other, enabling 3D printing of highly complex biological structures with a wide variety of cell types using inkjet printers

Date:
December 27, 2017

Source:
Osaka University

Summary:
Researchers develop a finely tuned enzyme-driven crosslinking method to glue together biological ink droplets and extend the range of cell types that can be handled by inkjet bioprinting. Such printing holds strong promise for regenerative medicine, such as in use of iPS cells.

 

This is a photograph of a 3-D hydrogel construct obtained through drop-on-drop multi-material bioprintinig.
Credit: Osaka University

 

 

Printed replacement human body parts might seem like science fiction, but this technology is rapidly becoming a reality with the potential to greatly contribute to regenerative medicine. Before any real applications, “bioprinting” still faces many technical challenges. Processing the bio-ink and making it stick to itself and hold the desired printed gel structure have been proving particularly difficult especially in inkjet printing. Few methods currently exist for gluing bio-ink droplets together and these do not work for every kind of cell, motivating new alternative approaches.

Building on their previous work, researchers at Osaka University have now refined an enzyme-driven approach to sticking biological ink droplets together, enabling complex biological structures to be printed. They recently published their findings in Macromolecular Rapid Communications.

Lead author, Shinji Sakai says, “Printing any kind of tissue structure is a complex process. The bio-ink must have low enough viscosity to flow through the inkjet printer, but also needs to rapidly form a highly viscose gel-like structure when printed. Our new approach meets these requirements while avoiding sodium alginate. In fact, the polymer we used offers excellent potential for tailoring the scaffold material for specific purposes.”

Currently, sodium alginate is the main gelling agent used for inkjet bioprinting, but has some compatibility problems with certain cell types. The researchers’ new approach is based on hydrogelation mediated by an enzyme, horseradish peroxidase, which can create cross-links between phenyl groups of an added polymer in the presence of the oxidant hydrogen peroxide.

Although hydrogen peroxide itself can also damage cells, the researchers carefully tuned the delivery of cells and hydrogen peroxide in separate droplets to limit their contact and keep the cells alive. More than 90% of the cells were viable in biological test gels prepared in this way. A number of complex test structures could also be grown from different types of cells.

“Advances in induced pluripotent stem cell technologies have made it possible for us to induce stem cells to differentiate in many different ways,” co-author Makoto Nakamura says. “Now we need new scaffolds so we can print and support these cells to move closer to achieving full 3D printing of functional tissues. Our new approach is highly versatile and should help all groups working to this goal.”

Story Source:

Materials provided by Osaka UniversityNote: Content may be edited for style and length.


Journal Reference:

  1. Shinji Sakai, Kohei Ueda, Enkhtuul Gantumur, Masahito Taya, Makoto Nakamura. Drop-On-Drop Multimaterial 3D Bioprinting Realized by Peroxidase-Mediated Cross-LinkingMacromolecular Rapid Communications, 2017; 1700534 DOI: 10.1002/marc.201700534

 

Source: Osaka University. “Growing organs a few ink drops at a time: Researchers refine method of making bio-ink droplets stick to each other, enabling 3D printing of highly complex biological structures with a wide variety of cell types using inkjet printers.” ScienceDaily. ScienceDaily, 27 December 2017. <www.sciencedaily.com/releases/2017/12/171227100040.htm>.

Date:
December 26, 2017

Source:
National Institute of Biomedical Imaging and Bioengineering

Summary:
Researchers have devised a biochemically formulated patch of dissolvable microneedles for the treatment of type 2 diabetes. The biochemical formula of mineralized compounds in the patch responds to blood chemistry to manage glucose automatically. In a proof-of-concept study performed with mice, the researchers showed that the chemicals interact in the bloodstream to regulate blood sugar for days at a time.

 

Concept illustration of microneedle device for type 2 diabetes treatment.
Credit: Chen lab, NIBIB.

 

 

For millions of people with type 2 diabetes, ongoing vigilance over the amount of sugar, or glucose, in their blood is the key to health. A finger prick before mealtimes and maybe an insulin injection is an uncomfortable but necessary routine.

Researchers with NIH’s National Institute of Biomedical Imaging and Bioengineering (NIBIB) have devised an innovative biochemical formula of mineralized compounds that interacts in the bloodstream to regulate blood sugar for days at a time. In a proof-of-concept study performed with mice, the researchers showed that the biochemically formulated patch of dissolvable microneedles can respond to blood chemistry to manage glucose automatically.

“This experimental approach could be a way to take advantage of the fact that persons with type 2 diabetes can still produce some insulin,” said Richard Leapman, Ph.D., NIBIB scientific director. “A weekly microneedle patch application would also be less complicated and painful than routines that require frequent blood testing.”

Insulin is a hormone made in the pancreas and secreted into the bloodstream to regulate glucose in response to food intake. It is needed to move glucose from the bloodstream into cells where the sugar can be converted to energy or stored. In type 1 diabetes, usually diagnosed in children and young adults, the body does not make insulin at all. Type 2 diabetes, which can be diagnosed at any age but more commonly as an adult, progressively lessens the body’s ability to make or use insulin. Untreated, diabetes can result in both vascular and nerve damage throughout the body, with debilitating impacts on the eyes, feet, kidneys, and heart.

Global incidence of all types of diabetes is about 285 million people, of which 90 percent have type 2 diabetes. Many require insulin therapy that is usually given by injection just under the skin in amounts that are calculated according to the deficit in naturally generated insulin in the blood. Insulin therapy is not managed well in half of all cases.

NIBIB researchers led by Xiaoyuan (Shawn) Chen, senior investigator in the Laboratory of Molecular Imaging and Nanomedicine, are working on an alternate therapy approach to regulate blood sugar levels in type 2 diabetes using a painless skin patch. In a Nov. 24, 2017, study published online in Nature Communications, the team applied the treatment to mice to demonstrate its potential effectiveness.

The base of the experimental patch is material called alginate, a gum-like natural substance extracted from brown algae. It is mixed with therapeutic agents and poured into a microneedle form to make the patch. “Alginate is a pliable material — it is soft, but not too soft,” Chen said. “It has to be able to poke the dermis, and while not a commonly used material for needles, it seems to work pretty well in this case.”

Chen’s team infused the alginate with a formula of biochemical particles that stimulates the body’s own insulin production when needed and curtails that stimulation when normal blood sugar concentration is reached. The responsive delivery system of the patch can meet the body’s need for days instead of being used up all at once.

“Diabetes is a very serious disease and affects a lot of people,” Chen said, explaining that his group is part of a crowded field of drug research and developers with competing ideas. “Everybody is looking for a long-acting formula.”

Pain-free skin patch responds to sugar levels for management of type 2 diabetes | National Institute of Biomedical Imaging and Bioengineering

Chen’s formula puts two drug compounds — exendin-4 and glucose oxidase — into one patch. The two compounds react with the blood chemistry to trigger insulin secretion. Each is matched with a phosphate mineral particle, which stabilizes the compound until it is needed. Acidity that occurs when sugar concentrations rise weakens the bond with the drug being held by one, but not the other mineral.

Exendin-4 is similar in genetic makeup to a molecule the body produces and secretes in the intestine in response to food intake. Though it is somewhat weaker than the naturally occurring molecule, the team chose exendin-4 for its application because exendin-4 does not degrade in the bloodstream for an hour or more, so can have long-lasting effect after being released. However, it can induce nausea when too much is absorbed. To control how quickly it is absorbed, the researchers combined exendin-4 with mineral particles of calcium phosphate, which stabilize it until another chemical reaction occurs. That chemical reaction is caused by the second drug compound in the patch — glucose oxidase — that is held in its mineral buffer of copper phosphate.

Chen explained that when blood sugar is elevated beyond a precise point, it triggers a reaction with copper phosphate and glucose oxidase to produce slight acidity, which causes calcium phosphate to release some exendin-4. Rising glucose levels trigger the release of exendin-4; but exendin-4 then gets insulin flowing to reduce the glucose level, which slows down and stops release of exendin-4. “That’s why we call it responsive, or smart, release,” said Chen. “Most current approaches involve constant release. Our approach creates a wave of fast release when needed and then slows or even stops the release when the glucose level is stable.”

The researchers demonstrated that a patch about half an inch square contained sufficient drug to control blood sugar levels in mice for a week. For the approach to advance as an application that people with type-2 diabetes can use, the team will need to perform tests to treat larger animals with a patch that contains proportionately more therapeutic compound. In addition to its size, the patch would need to be altered for application on human skin, likely requiring longer needles.

“We would need to scale up the size of the patch and optimize the length, shape, and morphology of the needles,” Chen said. “Also, the patch needs to be compatible with daily life, for instance allowing for showering or sweating.”

Chen is encouraged by the success of his experiments, and by research reports of steady progress by other experimental microneedle patch developers. For instance, others have completed early human studies with microneedle patch devices that contain insulin and that would benefit people with type 1 as well as type 2 diabetes. He hopes there will be lessons from development of those devices that can be applied to the microneedle patch that his team tested in this study.

Story Source:

Materials provided by National Institute of Biomedical Imaging and BioengineeringNote: Content may be edited for style and length.


Journal Reference:

  1. Wei Chen, Rui Tian, Can Xu, Bryant C. Yung, Guohao Wang, Yijing Liu, Qianqian Ni, Fuwu Zhang, Zijian Zhou, Jingjing Wang, Gang Niu, Ying Ma, Liwu Fu, Xiaoyuan Chen. Microneedle-array patches loaded with dual mineralized protein/peptide particles for type 2 diabetes therapyNature Communications, 2017; 8 (1) DOI: 10.1038/s41467-017-01764-1

 

Source: National Institute of Biomedical Imaging and Bioengineering. “Pain-free skin patch responds to sugar levels for management of type 2 diabetes.” ScienceDaily. ScienceDaily, 26 December 2017. <www.sciencedaily.com/releases/2017/12/171226134723.htm>.

Date:
December 23, 2017

Source:
University of Chicago

Summary:
Scientists have laid out a comprehensive theory for how our solar system could have formed in the wind-blown bubbles around a giant, long-dead star. The study addresses a nagging cosmic mystery about the abundance of two elements in our solar system compared to the rest of the galaxy.

 

This simulation shows how bubbles form over the course of 4.7 million years from the intense stellar winds off a massive star. UChicago scientists postulated how our own solar system could have formed in the dense shell of such a bubble.
Credit: V. Dwarkadas/D. Rosenberg

 

 

Despite the many impressive discoveries humans have made about the universe, scientists are still unsure about the birth story of our solar system.

Scientists with the University of Chicago have laid out a comprehensive theory for how our solar system could have formed in the wind-blown bubbles around a giant, long-dead star. Published Dec. 22 in the Astrophysical Journal, the study addresses a nagging cosmic mystery about the abundance of two elements in our solar system compared to the rest of the galaxy.

The general prevailing theory is that our solar system formed billions of years ago near a supernova. But the new scenario instead begins with a giant type of star called a Wolf-Rayet star, which is more than 40 to 50 times the size of our own sun. They burn the hottest of all stars, producing tons of elements which are flung off the surface in an intense stellar wind. As the Wolf-Rayet star sheds its mass, the stellar wind plows through the material that was around it, forming a bubble structure with a dense shell.

“The shell of such a bubble is a good place to produce stars,” because dust and gas become trapped inside where they can condense into stars, said coauthor Nicolas Dauphas, professor in the Department of Geophysical Sciences. The authors estimate that 1 percent to 16 percent of all sun-like stars could be formed in such stellar nurseries.

This setup differs from the supernova hypothesis in order to make sense of two isotopes that occur in strange proportions in the early solar system, compared to the rest of the galaxy. Meteorites left over from the early solar system tell us there was a lot of aluminium-26. In addition, studies, including a 2015 one by Dauphas and a former student, increasingly suggest we had less of the isotope iron-60.

This brings scientists up short, because supernovae produce both isotopes. “It begs the question of why one was injected into the solar system and the other was not,” said coauthor Vikram Dwarkadas, a research associate professor in Astronomy and Astrophysics.

This brought them to Wolf-Rayet stars, which release lots of aluminium-26, but no iron-60.

“The idea is that aluminum-26 flung from the Wolf-Rayet star is carried outwards on grains of dust formed around the star. These grains have enough momentum to punch through one side of the shell, where they are mostly destroyed — trapping the aluminum inside the shell,” Dwarkadas said. Eventually, part of the shell collapses inward due to gravity, forming our solar system.

As for the fate of the giant Wolf-Rayet star that sheltered us: Its life ended long ago, likely in a supernova explosion or a direct collapse to a black hole. A direct collapse to a black hole would produce little iron-60; if it was a supernova, the iron-60 created in the explosion may not have penetrated the bubble walls, or was distributed unequally.

Other authors on the paper included UChicago undergraduate student Peter Boyajian and Michael Bojazi and Brad Meyer of Clemson University.

Story Source:

Materials provided by University of ChicagoNote: Content may be edited for style and length.


Journal Reference:

  1. Vikram V. Dwarkadas, Nicolas Dauphas, Bradley Meyer, Peter Boyajian, Michael Bojazi. Triggered Star Formation inside the Shell of a Wolf–Rayet Bubble as the Origin of the Solar SystemThe Astrophysical Journal, 2017; 851 (2): 147 DOI: 10.3847/1538-4357/aa992e

 

Source: University of Chicago. “Scientists describe how solar system could have formed in bubble around giant star.” ScienceDaily. ScienceDaily, 23 December 2017. <www.sciencedaily.com/releases/2017/12/171223134850.htm>.

Date:
December 21, 2017

Source:
Stockholm University

Summary:
Using x-ray lasers, researchers have been able to map out how water fluctuates between two different states when it is cooled. At -44°C these fluctuations reach a maximum pointing to the fact that water can exist as two different distinct liquids.

 

Illustration showing fluctuations between regions of two different local structures (high density as red and low density liquid as blue) of water that depend on the temperature. Maxima in the thermodynamic response and correlation functions are observed as a function of temperature, when the numbers of molecules in the two structures become equal, resulting in strong enhancement in the anomalous properties of water in the deeply supercooled regime.
Credit: Stockholm University

 

 

Using x-ray lasers, researchers at Stockholm University have been able to map out how water fluctuates between two different states when it is cooled. At -44°C these fluctuations reach a maximum pointing to the fact that water can exist as two different distinct liquids. The findings will be published in the journal Science.

Water, both common and necessary for life on earth, behaves very strangely in comparison with other substances. How water’s density, specific heat, viscosity and compressibility respond to changes in pressure and temperature is completely opposite to other liquids that we know.

We all are aware that all matter shrinks when it is cooled resulting in an increase in the density. We would therefore expect that water would have high density at the freezing point. However, if we look at a glass of ice water, everything is upside down, since we expect that water at 0°C being surrounded by ice should be at the bottom of the glass, but of course as we know ice cubes float. Strangely enough for the liquid state, water is the densest at 4 degrees C, and therefore it stays on the bottom whether it’s in a glass or in an ocean.

If you chill water below 4 degrees, it starts to expand again. If you continue to cool pure water (where the rate of crystallization is low) to below 0, it continues to expand — the expansion even speeds up when it gets colder. Many more properties such as compressibility and heat capacity become increasingly strange as water is cooled. Now researchers at Stockholm University, with the help of ultra-short x-ray pulses at x-ray lasers in Japan and South Korea, have succeeded in determining that water reaches the peak of its strange behaviour at -44°C.

Water is unique, as it can exist in two liquid states that have different ways of bonding the water molecules together. The water fluctuates between these states as if it can’t make up its mind and these fluctuations reach a maximum at -44°C. It is this ability to shift from one liquid state into another that gives water its unusual properties and since the fluctuations increase upon cooling also the strangeness increases.

“What was special was that we were able to X-ray unimaginably fast before the ice froze and could observe how it fluctuated between the two states,” says Anders Nilsson, Professor of Chemical Physics at Stockholm University. “For decades there has been speculations and different theories to explain these remarkable properties and why they got stronger when water becomes colder. Now we have found such a maximum, which means that there should also be a critical point at higher pressures.”

Another remarkable finding of the study is that the unusual properties are different between normal and heavy water and more enhanced for the lighter one. “The differences between the two isotopes, H2O and D2O, given here shows the importance of nuclear quantum effects,” says Kyung Hwan Kim, postdoc in Chemical Physics at Stockholm University. “The possibility to make new discoveries in a much studied topic such as water is totally fascinating and a great inspiration for my further studies,” says Alexander Späh, PhD student in Chemical Physics at Stockholm University.

“It was a dream come true to be able to measure water under such low temperature condition without freezing” says Harshad Pathak, postdoc in Chemical Physics at Stockholm University. “Many attempts over the world have been made to look for this maximum.”

“There has been an intense debate about the origin of the strange properties of water for over a century since the early work of Wolfgang Röntgen,” further explains Anders Nilsson. “Researchers studying the physics of water can now settle on the model that water has a critical point in the supercooled regime. The next stage is to find the location of the critical in terms of pressure and temperature. A big challenge in the next few years.”

Story Source:

Materials provided by Stockholm UniversityNote: Content may be edited for style and length.


Journal Reference:

  1. Kyung Hwan Kim, Alexander Späh, Harshad Pathak, Fivos Perakis, Daniel Mariedahl, Katrin Amann-Winkel, Jonas A. Sellberg, Jae Hyuk Lee, Sangsoo Kim, Jaehyun Park, Ki Hyun Nam, Tetsuo Katayama, Anders Nilsson. Maxima in the thermodynamic response and correlation functions of deeply supercooled waterScience, 2017; 358 (6370): 1589 DOI: 10.1126/science.aap8269

 

Source: Stockholm University. “The origin of water’s unusual properties found.” ScienceDaily. ScienceDaily, 21 December 2017. <www.sciencedaily.com/releases/2017/12/171221143047.htm>.

Water on Mars absorbed like a sponge, new research suggests

Date:
December 20, 2017

Source:
University of Oxford

Summary:
Two new articles have shed light on why there is, presumably, no life on Mars. Although today’s Martian surface is barren, frozen and inhabitable, a trail of evidence points to a once warmer, wetter planet, where water flowed freely — and life may have thrived. The conundrum of what happened to this water is long standing and unsolved. However, new research suggests that this water is now locked in the Martian rocks.

 

This is image shows modern Mars (left) dry and barren, compared with the same scene over 3.5 billion years ago covered in water (right). The rocks of the surface were slowly reacting with the water, sequestering it into the Martian mantle leading to the dry, inhospitable scene shown on the left.
Credit: Jon Wade

 

 

When searching for life, scientists first look for an element key to sustaining it: fresh water.

Although today’s Martian surface is barren, frozen and inhabitable, a trail of evidence points to a once warmer, wetter planet, where water flowed freely. The conundrum of what happened to this water is long standing and unsolved. However, new research published in Nature suggests that this water is now locked in the Martian rocks.

Scientists at Oxford’s Department of Earth Sciences, propose that the Martian surface reacted with the water and then absorbed it, increasing the rocks oxidation in the process, making the planet uninhabitable.

Previous research has suggested that the majority of the water was lost to space as a result of the collapse of the planet’s magnetic field, when it was either swept away by high intensity solar winds or locked up as sub-surface ice. However, these theories do not explain where all of the water has gone.

Convinced that the planet’s minerology held the answer to this puzzling question, a team led by Dr Jon Wade, NERC Research Fellow in Oxford’s Department of Earth Sciences, applied modelling methods used to understand the composition of Earth rocks to calculate how much water could be removed from the Martian surface through reactions with rock. The team assessed the role that rock temperature, sub-surface pressure and general Martian make-up, have on the planetary surfaces.

The results revealed that the basalt rocks on Mars can hold approximately 25 per cent more water than those on Earth, and as a result drew the water from the Martian surface into its interior.

Dr Wade said: ‘People have thought about this question for a long time, but never tested the theory of the water being absorbed as a result of simple rock reactions. There are pockets of evidence that together, leads us to believe that a different reaction is needed to oxidise the Martian mantle. For instance, Martian meteorites are chemically reduced compared to the surface rocks, and compositionally look very different. One reason for this, and why Mars lost all of its water, could be in its minerology.

‘The Earth’s current system of plate tectonics prevents drastic changes in surface water levels, with wet rocks efficiently dehydrating before they enter the Earth’s relatively dry mantle. But neither early Earth nor Mars had this system of recycling water. On Mars, (water reacting with the freshly erupted lavas’ that form its basaltic crust, resulted in a sponge-like effect. The planet’s water then reacted with the rocks to form a variety of water bearing minerals. This water-rock reaction changed the rock mineralogy and caused the planetary surface to dry and become inhospitable to life.’

As to the question of why Earth has never experienced these changes, he said: ‘Mars is much smaller than Earth, with a different temperature profile and higher iron content of its silicate mantle. These are only subtle distinctions but they cause significant effects that, over time, add up. They made the surface of Mars more prone to reaction with surface water and able to form minerals that contain water. Because of these factors the planet’s geological chemistry naturally drags water down into the mantle, whereas on early Earth hydrated rocks tended to float until they dehydrate.’

The overarching message of Dr Wade’s paper, that planetary composition sets the tone for future habitability, is echoed in new research also published in Nature, examining the Earth’s salt levels. Co-written by Professor Chris Ballentine of Oxford’s Department of Earth Sciences, the research reveals that for life to form and be sustainable, the Earth’s halogen levels (Chlorine, Bromine and Iodine) have to be just right. Too much or too little could cause sterilisation. Previous studies have suggested that halogen level estimates in meteorites were too high. Compared to samples of the meteorites that formed the Earth, the ratio of salt to Earth is just too high.

Many theories have been put forward to explain the mystery of how this variation occurred, however, the two studies combined elevate the evidence and support a case for further investigation. Dr Wade said ‘Broadly speaking the inner planets in the solar system have similar composition, but subtle differences can cause dramatic differences — for example, rock chemistry. The biggest difference being, that Mars has more iron in its mantle rocks, as the planet formed under marginally more oxidising conditions.’

We know that Mars once had water, and the potential to sustain life, but by comparison little is known about the other planets, and the team are keen to change that.

Dr Wade, said: ‘To build on this work we want to test the effects of other sensitivities across the planets — very little is known about Venus for example. Questions like: what if the Earth had more or less iron in the mantle, how would that change the environment? What if the Earth was bigger or smaller? These answers will help us to understand how much of a role rock chemistry determines a planet’s future fate.

When looking for life on other planets it is not just about having the right bulk chemistry, but also very subtle things like the way the planet is put together, which may have big effects on whether water stays on the surface. These effects and their implications for other planets have not really been explored.’

Story Source:

Materials provided by University of OxfordNote: Content may be edited for style and length.


Journal References:

  1. Jon Wade, Brendan Dyck, Richard M. Palin, James D. P. Moore, Andrew J. Smye. The divergent fates of primitive hydrospheric water on Earth and MarsNature, 2017; 552 (7685): 391 DOI: 10.1038/nature25031
  2. Patricia L. Clay, Ray Burgess, Henner Busemann, Lorraine Ruzié-Hamilton, Bastian Joachim, James M. D. Day, Christopher J. Ballentine. Halogens in chondritic meteorites and terrestrial accretionNature, 2017; 551 (7682): 614 DOI: 10.1038/nature24625

 

Source: University of Oxford. “Mars: Not as dry as it seems: Water on Mars absorbed like a sponge, new research suggests.” ScienceDaily. ScienceDaily, 20 December 2017. <www.sciencedaily.com/releases/2017/12/171220131659.htm>.

Breakthrough in understanding of how cosmic rays from supernovae can influence Earth’s cloud cover and thereby climate

Date:
December 19, 2017

Source:
Technical University of Denmark

Summary:
The study reveals how atmospheric ions, produced by the energetic cosmic rays raining down through the atmosphere, helps the growth and formation of cloud condensation nuclei — the seeds necessary for forming clouds in the atmosphere.

 

Cosmic rays interacting with the Earth’s atmosphere producing ions that helps turn small aerosols into cloud condensation nuclei — seeds on which liquid water droplets form to make clouds. A proton with energy of 100 GeV interact at the top of the atmosphere and produces a cascade of secondary particles who ionize molecules when traveling through the air. One 100 GeV proton hits every m2 at the top of the atmosphere every second.
Credit: Illustration: H. Svensmark/DTU

 

 

The study reveals how atmospheric ions, produced by the energetic cosmic rays raining down through the atmosphere, helps the growth and formation of cloud condensation nuclei — the seeds necessary for forming clouds in the atmosphere. When the ionization in the atmosphere changes, the number of cloud condensation nuclei changes affecting the properties of clouds. More cloud condensation nuclei mean more clouds and a colder climate, and vice versa. Since clouds are essential for the amount of Solar energy reaching the surface of Earth the implications can be significant for our understanding of why climate has varied in the past and also for future climate changes.

Cloud condensation nuclei can be formed by the growth of small molecular clusters called aerosols. It has until now been assumed that additional small aerosols would not grow and become cloud condensation nuclei, since no mechanism was known to achieve this. The new results reveal, both theoretically and experimentally, how interactions between ions and aerosols can accelerate the growth by adding material to the small aerosols and thereby help them survive to become cloud condensation nuclei. It gives a physical foundation to the large body of empirical evidence showing that Solar activity plays a role in variations in Earth’s climate. For example, the Medieval Warm Period around year 1000 AD and the cold period in the Little Ice Age 1300-1900 AD both fits with changes in Solar activity.

“Finally we have the last piece of the puzzle explaining how particles from space affect climate on Earth. It gives an understanding of how changes caused by Solar activity or by super nova activity can change climate.” says Henrik Svensmark, from DTU Space at the Technical University of Denmark, lead author of the study. Co-authors are senior researcher Martin Bødker Enghoff (DTU Space), Professor Nir Shaviv (Hebrew University of Jerusalem), and Jacob Svensmark, (University of Copenhagen).

The new study

The fundamental new idea in the study is to include a contribution to growth of aerosols by the mass of the ions. Although the ions are not the most numerous constituents in the atmosphere the electro-magnetic interactions between ions and aerosols compensate for the scarcity and make fusion between ions and aerosols much more likely. Even at low ionization levels about 5% of the growth rate of aerosols is due to ions. In the case of a nearby super nova the effect can be more than 50% of the growth rate, which will have an impact on the clouds and the Earth’s temperature.

To achieve the results a theoretical description of the interactions between ions and aerosols was formulated along with an expression for the growth rate of the aerosols. The ideas were then tested experimentally in a large cloud chamber. Due to experimental constraints caused by the presence of chamber walls, the change in growth rate that had to be measured was of the order 1%, which poses a high demand on stability during the experiments, and experiments were repeated up to 100 times in order to obtain a good signal relative to unwanted fluctuations. Data was taken over a period of 2 years with total 3100 hours of data sampling. The results of the experiments agreed with the theoretical predictions.

The hypothesis in a nutshell

  • Cosmic rays, high-energy particles raining down from exploded stars, knock electrons out of air molecules. This produces ions, that is, positive and negative molecules in the atmosphere.
  • The ions help aerosols — clusters of mainly sulphuric acid and water molecules — to form and become stable against evaporation. This process is called nucleation. The small aerosols need to grow nearly a million times in mass in order to have an effect on clouds.
  • The second role of ions is that they accelerate the growth of the small aerosols into cloud condensation nuclei — seeds on which liquid water droplets form to make clouds. The more ions the more aerosols become cloud condensation nuclei. It is this second property of ions which is the new result published in Nature Communications.
  • Low clouds made with liquid water droplets cool the Earth’s surface.
  • Variations in the Sun’s magnetic activity alter the influx of cosmic rays to the Earth.
  • When the Sun is lazy, magnetically speaking, there are more cosmic rays and more low clouds, and the world is cooler.
  • When the Sun is active fewer cosmic rays reach the Earth and, with fewer low clouds, the world warms up.

The implications of the study suggests that the mechanism can have affected:

  • The climate changes observed during the 20th century
  • The coolings and warmings of around 2oC that have occurred repeatedly over the past 10,000 years, as the Sun’s activity and the cosmic ray influx have varied.
  • The much larger variations of up to 10oC occuring as the Sun and Earth travel through the Galaxy visiting regions with varying numbers of exploding stars.

Story Source:

Materials provided by Technical University of DenmarkNote: Content may be edited for style and length.


Journal Reference:

  1. H. Svensmark, M. B. Enghoff, N. J. Shaviv, J. Svensmark. Increased ionization supports growth of aerosols into cloud condensation nucleiNature Communications, 2017; 8 (1) DOI: 10.1038/s41467-017-02082-2

 

Source: Technical University of Denmark. “The missing link between exploding stars, clouds, and climate on Earth: Breakthrough in understanding of how cosmic rays from supernovae can influence Earth’s cloud cover and thereby climate.” ScienceDaily. ScienceDaily, 19 December 2017. <www.sciencedaily.com/releases/2017/12/171219091320.htm>.

Scientists analyze specimens from 3.465 billion years ago

Date:
December 18, 2017

Source:
University of California – Los Angeles

Summary:
A new analysis of the oldest known fossil microorganisms provides strong evidence to support an increasingly widespread understanding that life in the universe is common.

 

This is a 3.465 billion year-old fossil microorganism from Western Australia.
Credit: J. William Schopf/UCLA Center for the Study of Evolution and the Origin of Life

 

 

A new analysis of the oldest known fossil microorganisms provides strong evidence to support an increasingly widespread understanding that life in the universe is common.

The microorganisms, from Western Australia, are 3.465 billion years old. Scientists from UCLA and the University of Wisconsin-Madison report today in the journal Proceedings of the National Academy of Sciences that two of the species they studied appear to have performed a primitive form of photosynthesis, another apparently produced methane gas, and two others appear to have consumed methane and used it to build their cell walls.

The evidence that a diverse group of organisms had already evolved extremely early in the Earth’s history — combined with scientists’ knowledge of the vast number of stars in the universe and the growing understanding that planets orbit so many of them — strengthens the case for life existing elsewhere in the universe because it would be extremely unlikely that life formed quickly on Earth but did not arise anywhere else.

“By 3.465 billion years ago, life was already diverse on Earth; that’s clear — primitive photosynthesizers, methane producers, methane users,” said J. William Schopf, a professor of paleobiology in the UCLA College, and the study’s lead author. “These are the first data that show the very diverse organisms at that time in Earth’s history, and our previous research has shown that there were sulfur users 3.4 billion years ago as well.

“This tells us life had to have begun substantially earlier and it confirms that it was not difficult for primitive life to form and to evolve into more advanced microorganisms.”

Schopf said scientists still do not know how much earlier life might have begun.

“But, if the conditions are right, it looks like life in the universe should be widespread,” he said.

The study is the most detailed ever conducted on microorganisms preserved in such ancient fossils. Researchers led by Schopf first described the fossils in the journal Science in 1993, and then substantiated their biological origin in the journal Nature in 2002. But the new study is the first to establish what kind of biological microbial organisms they are, and how advanced or primitive they are.

For the new research, Schopf and his colleagues analyzed the microorganisms with cutting-edge technology called secondary ion mass spectroscopy, or SIMS, which reveals the ratio of carbon-12 to carbon-13 isotopes — information scientists can use to determine how the microorganisms lived. (Photosynthetic bacteria have different carbon signatures from methane producers and consumers, for example.) In 2000, Schopf became the first scientist to use SIMS to analyze microscopic fossils preserved in rocks; he said the technology will likely be used to study samples brought back from Mars for signs of life.

The Wisconsin researchers, led by geoscience professor John Valley, used a secondary ion mass spectrometer — one of just a few in the world — to separate the carbon from each fossil into its constituent isotopes and determine their ratios.

“The differences in carbon isotope ratios correlate with their shapes,” Valley said. “Their C-13-to-C-12 ratios are characteristic of biology and metabolic function.”

The fossils were formed at a time when there was very little oxygen in the atmosphere, Schopf said. He thinks that advanced photosynthesis had not yet evolved, and that oxygen first appeared on Earth approximately half a billion years later before its concentration in our atmosphere increased rapidly starting about 2 billion years ago.

Oxygen would have been poisonous to these microorganisms, and would have killed them, he said.

Primitive photosynthesizers are fairly rare on Earth today because they exist only in places where there is light but no oxygen — normally there is abundant oxygen anywhere there is light. And the existence of the rocks the scientists analyzed is also rather remarkable: The average lifetime of a rock exposed on the surface of the Earth is about 200 million years, Schopf said, adding that when he began his career, there was no fossil evidence of life dating back farther than 500 million years ago.

“The rocks we studied are about as far back as rocks go.”

While the study strongly suggests the presence of primitive life forms throughout the universe, Schopf said the presence of more advanced life is very possible but less certain.

One of the paper’s co-authors is Anatoliy Kudryavtsev, a senior scientist at UCLA’s Center for the Study of Evolution and the Origin of Life, of which Schopf is director. The research was funded by the NASA Astrobiology Institute.

In May 2017, a paper in PNAS by Schopf, UCLA graduate student Amanda Garcia and colleagues in Japan showed the Earth’s near-surface ocean temperature has dramatically decreased over the past 3.5 billion years. The work was based on their analysis of a type of ancient enzyme present in virtually all organisms.

In, 2015 Schopf was part of an international team of scientists that described in PNAS their discovery of the greatest absence of evolution ever reported — a type of deep-sea microorganism that appears not to have evolved over more than 2 billion years.

Story Source:

Materials provided by University of California – Los AngelesNote: Content may be edited for style and length.


Journal Reference:

  1. J. William Schopf, Kouki Kitajima, Michael J. Spicuzza, Anatoliy B. Kudryavtsev, John W. Valley. SIMS analyses of the oldest known assemblage of microfossils document their taxon-correlated carbon isotope compositionsProceedings of the National Academy of Sciences, 2017; 201718063 DOI: 10.1073/pnas.1718063115

 

Source: University of California – Los Angeles. “Ancient fossil microorganisms indicate that life in the universe is common: Scientists analyze specimens from 3.465 billion years ago.” ScienceDaily. ScienceDaily, 18 December 2017. <www.sciencedaily.com/releases/2017/12/171218154925.htm>.

Date:
December 14, 2017

Source:
NASA/Jet Propulsion Laboratory

Summary:
Our solar system now is tied for most number of planets around a single star, with the recent discovery of an eighth planet circling Kepler-90, a Sun-like star 2,545 light years from Earth. The planet was discovered in data from NASA’s Kepler Space Telescope.

 

With the discovery of an eighth planet, the Kepler-90 system is the first to tie with our solar system in number of planets. Artist’s concept.
Credit: NASA/Ames Research Center/Wendy Stenzel

 

 

Our solar system now is tied for most number of planets around a single star, with the recent discovery of an eighth planet circling Kepler-90, a Sun-like star 2,545 light years from Earth. The planet was discovered in data from NASA’s Kepler Space Telescope.

The newly-discovered Kepler-90i — a sizzling hot, rocky planet that orbits its star once every 14.4 days — was found using machine learning from Google. Machine learning is an approach to artificial intelligence in which computers “learn.” In this case, computers learned to identify planets by finding in Kepler data instances where the telescope recorded changes in starlight caused by planets beyond our solar system, known as exoplanets.

“Just as we expected, there are exciting discoveries lurking in our archived Kepler data, waiting for the right tool or technology to unearth them,” said Paul Hertz, director of NASA’s Astrophysics Division in Washington. “This finding shows that our data will be a treasure trove available to innovative researchers for years to come.”

The discovery came about after researchers Christopher Shallue and Andrew Vanderburg trained a computer to learn how to identify exoplanets in the light readings recorded by Kepler — the miniscule change in brightness captured when a planet passed in front of, or transited, a star. Inspired by the way neurons connect in the human brain, this artificial “neural network” sifted through Kepler data and found weak transit signals from a previously-missed eighth planet orbiting Kepler-90, in the constellation Draco.

Machine learning has previously been used in searches of the Kepler database, and this continuing research demonstrates that neural networks are a promising tool in finding some of the weakest signals of distant worlds.

Other planetary systems probably hold more promise for life than Kepler-90. About 30 percent larger than Earth, Kepler-90i is so close to its star that its average surface temperature is believed to exceed 800 degrees Fahrenheit, on par with Mercury. Its outermost planet, Kepler-90h, orbits at a similar distance to its star as Earth does to the Sun.

“The Kepler-90 star system is like a mini version of our solar system. You have small planets inside and big planets outside, but everything is scrunched in much closer,” said Vanderburg, a NASA Sagan Postdoctoral Fellow and astronomer at the University of Texas at Austin.

Shallue, a senior software engineer with Google’s research team Google AI, came up with the idea to apply a neural network to Kepler data. He became interested in exoplanet discovery after learning that astronomy, like other branches of science, is rapidly being inundated with data as the technology for data collection from space advances.

“In my spare time, I started Googling for ‘finding exoplanets with large data sets’ and found out about the Kepler mission and the huge data set available,” said Shallue. “Machine learning really shines in situations where there is so much data that humans can’t search it for themselves.”

Kepler’s four-year dataset consists of 35,000 possible planetary signals. Automated tests, and sometimes human eyes, are used to verify the most promising signals in the data. However, the weakest signals often are missed using these methods. Shallue and Vanderburg thought there could be more interesting exoplanet discoveries faintly lurking in the data.

First, they trained the neural network to identify transiting exoplanets using a set of 15,000 previously vetted signals from the Kepler exoplanet catalogue. In the test set, the neural network correctly identified true planets and false positives 96 percent of the time. Then, with the neural network having “learned” to detect the pattern of a transiting exoplanet, the researchers directed their model to search for weaker signals in 670 star systems that already had multiple known planets. Their assumption was that multiple-planet systems would be the best places to look for more exoplanets.

“We got lots of false positives of planets, but also potentially more real planets,” said Vanderburg. “It’s like sifting through rocks to find jewels. If you have a finer sieve then you will catch more rocks but you might catch more jewels, as well.”

Kepler-90i wasn’t the only jewel this neural network sifted out. In the Kepler-80 system, they found a sixth planet. This one, the Earth-sized Kepler-80g, and four of its neighboring planets form what is called a resonant chain — where planets are locked by their mutual gravity in a rhythmic orbital dance. The result is an extremely stable system, similar to the seven planets in the TRAPPIST-1 system.

Their research paper reporting these findings has been accepted for publication in The Astronomical Journal. Shallue and Vanderburg plan to apply their neural network to Kepler’s full set of more than 150,000 stars.

Kepler has produced an unprecedented data set for exoplanet hunting. After gazing at one patch of space for four years, the spacecraft now is operating on an extended mission and switches its field of view every 80 days.

“These results demonstrate the enduring value of Kepler’s mission,” said Jessie Dotson, Kepler’s project scientist at NASA’s Ames Research Center in California’s Silicon Valley. “New ways of looking at the data — such as this early-stage research to apply machine learning algorithms — promise to continue to yield significant advances in our understanding of planetary systems around other stars. I’m sure there are more firsts in the data waiting for people to find them.”

Ames manages the Kepler and K2 missions for NASA’s Science Mission Directorate in Washington. NASA’s Jet Propulsion Laboratory in Pasadena, California, managed Kepler mission development. Ball Aerospace & Technologies Corporation operates the flight system with support from the Laboratory for Atmospheric and Space Physics at the University of Colorado in Boulder. This work was performed through the Carl Sagan Postdoctoral Fellowship Program executed by the NASA Exoplanet Science Institute.

For more information about the Kepler mission, visit: https://www.nasa.gov/kepler

Story Source:

Materials provided by NASA/Jet Propulsion LaboratoryNote: Content may be edited for style and length.

 

Source: NASA/Jet Propulsion Laboratory. “Artificial intelligence, NASA data used to discover eighth planet circling distant star.” ScienceDaily. ScienceDaily, 14 December 2017. <www.sciencedaily.com/releases/2017/12/171214141416.htm>.

Date:
December 14, 2017

Source:
Cornell University

Summary:
While engineers have had success building tiny, insect-like robots, programming them to behave autonomously like real insects continues to present technical challenges. Engineers have recently been experimenting with a new type of programming that mimics the way an insect’s brain works, which could soon have people wondering if that fly on the wall is actually a fly.

 

RoboBees manufactured by the Harvard Microrobotics Lab have a 3 centimeter wingspan and weigh only 80 milligrams. Cornell engineers are developing new programming that will make them more autonomous and adaptable to complex environments.
Credit: Harvard Microrobotics Lab

 

 

While engineers have had success building tiny, insect-like robots, programming them to behave autonomously like real insects continues to present technical challenges. A group of Cornell engineers has been experimenting with a new type of programming that mimics the way an insect’s brain works, which could soon have people wondering if that fly on the wall is actually a fly.

The amount of computer processing power needed for a robot to sense a gust of wind, using tiny hair-like metal probes imbedded on its wings, adjust its flight accordingly, and plan its path as it attempts to land on a swaying flower would require it to carry a desktop-size computer on its back. Silvia Ferrari, professor of mechanical and aerospace engineering and director of the Laboratory for Intelligent Systems and Controls, sees the emergence of neuromorphic computer chips as a way to shrink a robot’s payload.

Unlike traditional chips that process combinations of 0s and 1s as binary code, neuromorphic chips process spikes of electrical current that fire in complex combinations, similar to how neurons fire inside a brain. Ferrari’s lab is developing a new class of “event-based” sensing and control algorithms that mimic neural activity and can be implemented on neuromorphic chips. Because the chips require significantly less power than traditional processors, they allow engineers to pack more computation into the same payload.

Ferrari’s lab has teamed up with the Harvard Microrobotics Laboratory, which has developed an 80-milligram flying RoboBee outfitted with a number of vision, optical flow and motion sensors. While the robot currently remains tethered to a power source, Harvard researchers are working on eliminating the restraint with the development of new power sources. The Cornell algorithms will help make RoboBee more autonomous and adaptable to complex environments without significantly increasing its weight.

“Getting hit by a wind gust or a swinging door would cause these small robots to lose control. We’re developing sensors and algorithms to allow RoboBee to avoid the crash, or if crashing, survive and still fly,” said Ferrari. “You can’t really rely on prior modeling of the robot to do this, so we want to develop learning controllers that can adapt to any situation.”

To speed development of the event-based algorithms, a virtual simulator was created by Taylor Clawson, a doctoral student in Ferrari’s lab. The physics-based simulator models the RoboBee and the instantaneous aerodynamic forces it faces during each wing stroke. As a result, the model can accurately predict RoboBee’s motions during flights through complex environments.

“The simulation is used both in testing the algorithms and in designing them,” said Clawson, who helped has successfully developed an autonomous flight controller for the robot using biologically inspired programming that functions as a neural network. “This network is capable of learning in real time to account for irregularities in the robot introduced during manufacturing, which make the robot significantly more challenging to control.”

Aside from greater autonomy and resiliency, Ferrari said her lab plans to help outfit RoboBee with new micro devices such as a camera, expanded antennae for tactile feedback, contact sensors on the robot’s feet and airflow sensors that look like tiny hairs.

“We’re using RoboBee as a benchmark robot because it’s so challenging, but we think other robots that are already untethered would greatly benefit from this development because they have the same issues in terms of power,” said Ferrari.

One robot that is already benefiting is the Harvard Ambulatory Microrobot, a four-legged machine just 17 millimeters long and weighing less than 3 grams. It can scamper at a speed of .44 meters-per-second, but Ferrari’s lab is developing event-based algorithms that will help complement the robot’s speed with agility.

Ferrari is continuing the work using a four-year, $1 million grant from the Office of Naval Research. She’s also collaborating with leading research groups from a number of universities fabricating neuromorphic chips and sensors.

Story Source:

Materials provided by Cornell University. Original written by Syl Kacapyr. Note: Content may be edited for style and length.

 

Source: Cornell University. “Engineers program tiny robots to move, think like insects.” ScienceDaily. ScienceDaily, 14 December 2017. <www.sciencedaily.com/releases/2017/12/171214141923.htm>.

 

Next Page →