Monthly Archives: May 2016

Diamond-based electronics?

A May 24, 2016 news item on ScienceDaily describes the latest research on using diamonds as semiconductors,

Along with being a “girl’s best friend,” diamonds also have remarkable properties that could make them ideal semiconductors. This is welcome news for electronics; semiconductors are needed to meet the rising demand for more efficient electronics that deliver and convert power.

The thirst for electronics is unlikely to cease and almost every appliance or device requires a suite of electronics that transfer, convert and control power. Now, researchers have taken an important step toward that technology with a new way to dope single crystals of diamonds, a crucial process for building electronic devices.

A May 24, 2016 American Institute of Physics (AIP) news release (also on EurekAlert), which originated the news item, provides more detail,

For power electronics, diamonds could serve as the perfect material. They are thermally conductive, which means diamond-based devices would dissipate heat quickly and easily, foregoing the need for bulky and expensive methods for cooling. Diamond can also handle high voltages and power. Electrical currents also flow through diamonds quickly, meaning the material would make for energy efficient devices.

But among the biggest challenges to making diamond-based devices is doping, a process in which other elements are integrated into the semiconductor to change its properties. Because of diamond’s rigid crystalline structure, doping is difficult.

Currently, you can dope diamond by coating the crystal with boron and heating it to 1450 degrees Celsius. But it’s difficult to remove the boron coating at the end. This method only works on diamonds consisting of multiple crystals stuck together. Because such polydiamonds have irregularities between the crystals, single-crystals would be superior semiconductors.

You can dope single crystals by injecting boron atoms while growing the crystals artificially. The problem is the process requires powerful microwaves that can degrade the quality of the crystal.

Now, Ma [Zhengqiang (Jack) Ma, an electrical and computer engineering professor at the University of Wisconsin-Madison] and his colleagues have found a way to dope single-crystal diamonds with boron at relatively low temperatures and without any degradation. The researchers discovered if you bond a single-crystal diamond with a piece of silicon doped with boron, and heat it to 800 degrees Celsius, which is low compared to the conventional techniques, the boron atoms will migrate from the silicon to the diamond. It turns out that the boron-doped silicon has defects such as vacancies, where an atom is missing in the lattice structure. Carbon atoms from the diamond will fill those vacancies, leaving empty spots for boron atoms.

This technique also allows for selective doping, which means more control when making devices. You can choose where to dope a single-crystal diamond simply by bonding the silicon to that spot.

The new method only works for P-type doping, where the semiconductor is doped with an element that provides positive charge carriers (in this case, the absence of electrons, called holes).

“We feel like we found a very easy, inexpensive, and effective way to do it,” Ma said. The researchers are already working on a simple device using P-type single-crystal diamond semiconductors.

But to make electronic devices like transistors, you need N-type doping that gives the semiconductor negative charge carriers (electrons). And other barriers remain. Diamond is expensive and single crystals are very small.

Still, Ma says, achieving P-type doping is an important step, and might inspire others to find solutions for the remaining challenges. Eventually, he said, single-crystal diamond could be useful everywhere — perfect, for instance, for delivering power through the grid.

Here’s an image the researchers have released,

Optical image of a diode array on a natural single crystalline diamond plate. (The image looks blurred due to light scattering by the array of small pads on top of the diamond plate.) Inset shows the deposited anode metal on top of heavy doped Si nanomembrane that is bonded to natural single crystalline diamond. CREDIT: Jung-Hun Seo

Optical image of a diode array on a natural single crystalline diamond plate. (The image looks blurred due to light scattering by the array of small pads on top of the diamond plate.) Inset shows the deposited anode metal on top of heavy doped Si nanomembrane that is bonded to natural single crystalline diamond. CREDIT: Jung-Hun Seo Courtesy: American Institute of Physics

Here’s a link to and a citation for the paper,

Thermal diffusion boron doping of single-crystal natural diamond by Jung-Hun Seo, Henry Wu, Solomon Mikael, Hongyi Mi, James P. Blanchard, Giri Venkataramanan, Weidong Zhou, Shaoqin Gong, Dane Morgan, and Zhenqiang Ma. J. Appl. Phys. 119, 205703 (2016);

This paper appears to be open access.

Better blood vessel growth for regenerative medicine?

If the organs and tissues grown in labs are to be successfully transplanted into bodies, then growing the blood vessels needed to maintain them becomes very important. A May 24, 2016 news item on ScienceDaily describes a new technique for the growing the vessels,

Growing tissues and organs in the lab for transplantation into patients could become easier after scientists discovered an effective way to produce three-dimensional networks of blood vessels, vital for tissue survival yet a current stumbling block in regenerative medicine.

In addition the technique to grow the blood vessels in a 3D scaffold cuts down on the risk of transplant rejection because it uses cells from the patient. It was developed by researchers from the University of Bath’s Department of Pharmacy and Pharmacology, working with colleagues at Bristol Heart Institute.

A May 24 (?), 2016 University of Bath (UK) press release, which originated the news item, expands on the theme (Note: Links have been removed),

So far the shortage of adequate patient-derived scaffolds that can support blood vessel growth has been a major limitation for regenerative medicine and tissue engineering.

Other methods only allow limited formation of small blood vessels such as capillaries, which makes tissue less likely to successfully transplant into a patient. In addition other methods of tissue growth require the use of animal products, unnecessary in this technique which uses human platelet lysate gel (hPLG) and endothelial progenitor cells (EPCs) – a type of cell which helps maintain blood vessel walls.

Dr Giordano Pula, Lecturer in Pharmacology at the University of Bath and head of the research team making the discovery, said: “A major challenge in tissue engineering and regenerative medicine is providing the new tissue with a network of blood vessels, and linking this to the patient’s existing blood supply; this is vital for the tissue’s survival and integration with adjacent tissues.

Dr Paul De Bank, Senior Lecturer in Pharmaceutics at the University of Bath and co-author of the paper, said: “By embedding EPCs in a gel derived from platelets, both of which can be isolated from the patient’s blood, we have demonstrated the formation of a network of small vessels. What is more, the gel contains a number of different growth factors which can induce existing blood vessels to infiltrate the gel and form connections with the new structures. Combining tissue-specific cells with this EPC-containing gel offers the potential for the formation of fully vascularised, functional tissues or organs, which integrate seamlessly with the patient.

“This discovery has the potential to accelerate the development of regenerative medicine applications.”

Professor Peter Weissberg, Medical Director of the British Heart Foundation, said: “Over a half a million people in the UK are living with heart failure, a disabling condition which can leave people unable to carry out everyday activities such as climbing the stairs or even walking to the shops. This regenerative research brings the British Heart Foundation’s goal to mend a broken heart and beat heart failure one step closer.

“All living tissues, including new heart muscle, need a blood supply. One of the fundamental goals of regenerative medicine is to find ways to grow a new blood supply from scratch. Previous attempts at this using human cells and synthetic scaffolds have met with only limited success.

“The beauty of this new approach is that components of a person’s own blood could be manipulated to create a scaffold on which new blood vessels could grow. This increases the likelihood that the new tissue will be integrated into the patient’s body which, if proven successful with more research, could improve the lives of people affected by heart failure.”

Here’s a link to and a citation for the paper,

Platelet lysate gel and endothelial progenitors stimulate microvascular network formation in vitro: tissue engineering implications by Tiago M. Fortunato, Cristina Beltrami, Costanza Emanueli, Paul A. De Bank & Giordano Pula. Scientific Reports 6, Article number: 25326 (2016)  doi:10.1038/srep25326 Published online: 04 May 2016

This is an open access paper.

One of the criticisms of Paolo Macchiarini’s work with synthetic tracheas centered around blood supply to the cells (from my April 19, 2016 posting; it was part 1 of a 2-part series),

This ground-breaking achievement consisted of bringing to life a dead windpipe from a donor, by putting it in a plastic box, a so-called ‘bioreactor’ together with bone marrow fluid (stem cells). A few weeks later, I [Pierre Delaere*]  wrote a letter to The Lancet, pointing out:

“The main drawback of the proposed reconstruction is the lack of an intrinsic blood supply to the trachea. We know that a good blood supply is the first requirement in all other tissue and organ transplantations. Therefore, the reported success of this technique is questionable” (correspondence by Delaere and Hermans, Lancet 2009).

The excerpt you’ve just seen features part of an open letter Pierre Delaere (a long time Macchiarini critic), published in Leonid Schneider’s blog ‘For Better Science’ in an April 2, 2016 posting.

Getting back to Bath, this is exciting stuff and I hope the research is reproducible.

Deep learning for cosmetics

Deep learning seems to be a synonym for artificial intelligence if a May 24, 2016 Insilico Medicine news release on EurekAlert about its use in the fields of cosmetics and as an alternative to testing animals is to be believed (Note: Links have been removed),

In addition to heading Insilico Medicine, Inc, a big data analytics company focused on applying advanced signaling pathway activation analysis and deep learning methods to biomarker and drug discovery in cancer and age-related diseases, Alex Zhavoronkov, PhD is the co-founder and principal scientist of Youth Laboratories, a company focusing on applying machine learning methods to evaluating the condition of human skin and general health status using multimodal inputs. The company developed an app called RYNKL, a mobile app for evaluating the effectiveness of various anti-aging interventions by analyzing “wrinkleness” and other parameters. The app was developed using funds from a Kickstarter crowdfunding campaign and is now being extensively tested and improved. The company also developed a platform for running online beauty competitions, where humans are evaluated by a panel of robot judges. Teams of programmers also compete on the development of most innovative algorithms to evaluate humans.

“One of my goals in life is to minimize unnecessary animal testing in areas, where computer simulations can be even more relevant to humans. Serendipitously, some of our approaches find surprising new applications in the beauty industry, which has moved away from human testing and is moving towards personalizing cosmetics and beauty products. We are happy to present our research results to a very relevant audience at this major industry event”, said Alex Zhavoronkov, CEO of Insilico Medicine, Inc.

Artificial intelligence is entering every aspect of our daily life. Deep learning systems are already outperforming humans in image and text recognition and we would like to bring some of the most innovative players like Insilico Medicine, who dare to work with gene expression, imaging and drug data to find novel ways to keep us healthy, young and beautiful”, said Irina Kremlin, director of INNOCOS.

Here’s a link to and a citation for the paper,

Deep biomarkers of human aging: Application of deep neural networks to biomarker development by Evgeny Putin, Polina Mamoshina, Alexander Aliper, Mikhail Korzinkin, Alexey Moskalev, Alexey Kolosov, Alexander Ostrovskiy, Charles Cantor, Jan Vijg, and Alex Zhavoronkov. Aging May 2016 vol. 8, no. 5

This is an open access paper.

You can find out more about In Silico Medicine here and RINKL here. I was not able to find a website for Youth Laboratories.

A de-icer and a preventative for airplane wings from Rice University

I last mentioned this graphene-based work (from James Tour at Rice University in Texas, US) on de-icing not just airplane wings but also windshields, skyscrapers and more in a Sept. 17, 2014 posting. The latest study indicates the technology could be used as a preventative according to a May 23, 2016 news item on,

Rice University scientists have advanced their graphene-based de-icer to serve a dual purpose. The new material still melts ice from wings and wires when conditions get too cold. But if the air is above 7 degrees Fahrenheit, ice won’t form at all.

A May 23, 2016 Rice University news release (also on EurekAlert), which originated the news item, goes on to describe the work in more detail,

The Rice lab of chemist James Tour gave its de-icer superhydrophobic (water-repelling) capabilities that passively prevent water from freezing above 7 degrees. The tough film that forms when the de-icer is sprayed on a surface is made of atom-thin graphene nanoribbons that are conductive, so the material can also be heated with electricity to melt ice and snow in colder conditions.

The material can be spray-coated, making it suitable for large applications like aircraft, power lines, radar domes and ships, according to the researchers. …

“We’ve learned to make an ice-resistant material for milder conditions in which heating isn’t even necessary, but having the option is useful,” Tour said. “What we now have is a very thin, robust coating that can keep large areas free of ice and snow in a wide range of conditions.”

Tour, lead authors Tuo Wang, a Rice graduate student, and Yonghao Zheng, a Rice postdoctoral researcher, and their colleagues tested the film on glass and plastic.

Materials are superhydrophobic if they have a water-contact angle larger than 150 degrees. The term refers to the angle at which the surface of the water meets the surface of the material. The greater the beading, the higher the angle. An angle of 0 degrees is basically a puddle, while a maximum angle of 180 degrees defines a sphere just touching the surface.

The Rice films use graphene nanoribbons modified with a fluorine compound to enhance their hydrophobicity. They found that nanoribbons modified with longer perfluorinated chains resulted in films with a higher contact angle, suggesting that the films are tunable for particular conditions, Tour said.

Warming test surfaces to room temperature and cooling again had no effect on the film’s properties, he said.

The researchers discovered that below 7 degrees, water would condense within the structure’s pores, causing the surface to lose both its superhydrophobic and ice-phobic properties. At that point, applying at least 12 volts of electricity warmed them enough to retain its repellant properties.

Applying 40 volts to the film brought it to room temperature, even if the ambient temperature was 25 degrees below zero. Ice allowed to form at that temperature melted after 90 seconds of resistive heating.

The researchers found that while effective, the de-icing mode did not remove water completely, as some remained trapped in the pores between linked nanoribbon bundles. Adding a lubricant with a low melting point (minus 61 degrees F) to the film made the surface slippery, sped de-icing and saved energy.

Here’s a link to and a citation for the paper,

Passive Anti-icing and Active Deicing Films by Tuo Wang, Yonghao Zheng, Abdul-Rahman O. Raji, Yilun Li, William K.A. Sikkema, and James M. Tour. ACS Appl. Mater. Interfaces, Just Accepted Manuscript DOI: 10.1021/acsami.6b03060 Publication Date (Web): May 18, 2016

Copyright © 2016 American Chemical Society

This paper is behind a paywall.

English ivy’s stickiness may be useful

Researchers have discovered the secret to English ivy’s stickiness and they hope that secret will lead to improved wound healing and more according to a May 24, 2016 news item on Nanowerk,

English ivy’s natural glue might hold the key to new approaches to wound healing, stronger armor for the military and maybe even cosmetics with better staying power.

New research from The Ohio State University illuminates the tiny particles responsible for ivy’s ability to latch on so tight to trees and buildings that it can withstand hurricanes and tornadoes. (Not to mention infuriate those trying to rid their homes of the vigorous green climber.)

The researchers pinpointed the spherical particles within English ivy’s adhesive and identified the primary protein within them.

A May 23, 2016 Ohio State University news release (also on EurekAlert) by Misti Crane, which originated the news item, expands on the theme,

“By understanding the proteins that give rise to ivy’s strength, we can give rise to approaches to engineer new bio-inspired adhesives for medical and industry products,” said Mingjun Zhang, the biomedical engineering professor who led the work.

“It’s a milestone to resolve this mystery. We now know the secret of this adhesive and the underlying molecular mechanism,” said Zhang, who focuses his work on finding answers in nature for vexing problems in medicine.

“Ivy has these very tiny hairy structures that have a wonderful interaction with the surface as the plant climbs. One day I was looking at the ivy in the backyard and I was amazed at the force,” Zhang said.Like many scientists before him, Charles Darwin among them, Zhang found himself captivated by English ivy – the physics of it, the sheer strength of it. The study appears today in the journal Proceedings of the National Academy of Sciences.

“It’s very difficult to tear down, even in a natural disaster. It’s one of the strongest adhesive forces in nature.”

When he and his team took a look at the ivy’s glue with a powerful atomic-force microscope, they were able to identify a previously unknown element in its adhesive.

Zhang said particles rich in those proteins have exceptional adhesive abilities – abilities that could be used to the advantage of many, from biomedical engineers to paint makers.The tiny particles inside the glue on their laboratory slides turned out to be primarily made up of arabinogalactan proteins. And when the scientists investigated further, they discovered that the driving force behind the curing of the glue was a calcium-mediated interaction between the proteins and pectin in the gelatinous liquid that oozes from ivy as it climbs.

Zhang, a member of Ohio State’s Davis Heart and Lung Research Institute, is particularly interested in bioadhesives that could aid in wound healing after injury or surgeries. Others, notably the U.S. military, are interested in surface-coating applications for purposes that include strengthening armor systems, he said.

Many plants are excellent climbers, but scientists have had limited information about the adhesives that enable those plants to affix themselves to walls, fences and just about anything in their way, he said.

“When climbing, ivy secretes these tiny nanoparticles which make initial surface contact. Due to their high uniformity and low viscosity, they can attach to large areas on various surfaces,” Zhang said.

After the water evaporates, a chemical bond forms, Zhang said.

“It’s really a nature-made amazing mechanism for high-strength adhesion,” he said.

The glue doesn’t just sit on the surface of the object that the ivy is clinging to, he said. It finds its way into openings invisible to the naked eye, further solidifying its bond.

To confirm what they found, Zhang and his collaborators used the nanoparticles to reconstruct a simple glue that mimics ivy adhesive. Advanced bioadhesives based on this research will take more time and research.

In addition to its strength, ivy adhesive has other properties that make it appealing to scientists looking for answers to engineering quandaries, Zhang said.

“Under moisture or high or low temperatures, it’s not easily damaged,” he said. “Ivy is very resistant to various environmental conditions, which makes the adhesive a particularly interesting candidate for the development of armor coatings.”

Ivy also is considered a pest because it can be destructive to buildings and bridges. Knowing what’s at the heart of its sticking ability could help scientists unearth approaches to resist the plant, Zhang said.

Zhang and his work have been featured here before in a Jan. 7, 2013 posting about flesh-eating fungus and in a July 22, 2010 posting about English ivy and sunscreens.

Here’s a link to and a citation for Zhang’s latest paper,

Nanospherical arabinogalactan proteins are a key component of the high-strength adhesive secreted by English ivy by Yujian Huang, Yongzhong Wang, Li Tan, Leming Sun, Jennifer Petrosino, Mei-Zhen Cui, Feng Hao, and Mingjun Zhang. PNAS [Proceedings of the National Academy of Sciences] 2016 doi: 10.1073/pnas.1600406113 Published ahead of print May 23, 2016,

This paper is behind a paywall.

Scented video games: a nanotechnology project in Europe

Ten years ago when I was working on a master’s degree (creative writing and new media), I was part of a group presentation on multimedia and to prepare started a conversation about scent as part of a multimedia experience. Our group leader was somewhat outraged. He’d led international multimedia projects and as far as he was concerned the ‘scent’ discussion was a waste of time when we were trying to prepare a major presentation.

He was right and wrong. I think you’re supposed to have these discussions when you’re learning and exploring ideas but, in 2006, there wasn’t much work of that type to discuss. It seems things may be changing according to a May 21, 2016 news item on Nanowerk (Note: A link has been removed),

Controlled odour emission could transform video games and television viewing experiences and benefit industries such as pest control and medicine [emphasis mine]. The NANOSMELL project aims to switch smells on and off by tagging artificial odorants with nanoparticles exposed to electromagnetic field.

I wonder if the medicinal possibilities include nanotechnology-enabled aroma therapy?

Getting back to the news, a May 10, 2016 European Commission press release, which originated the news item, expands on the theme,

The ‘smellyvision’ – a TV that offers olfactory as well as visual stimulation – has been a science fiction staple for years. However, realising this concept has proved difficult given the sheer complexity of how smell works and the technical challenges of emitting odours on demand.

NANOSMELL will specifically address these two challenges by developing artificial smells that can be switched on and off remotely. This would be achieved by tagging specific DNA-based artificial odorants – chemical compounds that give off smells – with nanoparticles that respond to external electromagnetic fields.

With the ability to remotely control these artificial odours, the project team would then be able to examine exactly how olfactory receptors respond. Sensory imaging to investigate the patterns of neural activity and behavioural tests will be carried out in animals.

The project would next apply artificial odorants to the human olfactory system and measure perceptions by switching artificial smells on and off. Researchers will also assess whether artificial odorants have a role to play in wound healing by placing olfactory receptors in skin.

The researchers aim to develop controllable odour-emitting components that will further understanding of smell and open the door to novel odour-emitting applications in fields ranging from entertainment to medicine.

Project details

  • Project acronym: NanoSmell
  • Participants: Israel (Coordinator), Spain, Germany, Switzerland
  • Project Reference N° 662629
  • Total cost: € 3 979 069
  • EU contribution: € 3 979 069
  • Duration:September 2015 – September 2019

You can find more information on the European Commission’s NANOSMELL project page.

Implications of nanoplastic in the aquatic food chain

As plastic breaks down in the oceans into plastic nanoparticles, they enter the food chain when they are ingested by plankton. Researchers in Sweden have published a study about the process. From a May 23, 2016 news item on ScienceDaily,

Plastic accounts for nearly eighty per cent of all waste found in our oceans, gradually breaking down into smaller and smaller particles. New research from Lund University in Sweden investigates how nanosized plastic particles affect aquatic animals in different parts of the food chain.

“Not very many studies have been done on this topic before. Plastic particles of such a small size are difficult to study,” says Karin Mattsson.

A May 23, 2016 Lund University press release, which originated the news item, provides more detail,

“We tested how polystyrene plastic particles of different sizes, charge and surface affect the zooplankton Daphnia. It turned out that the size of the nanoparticles that were most toxic to the Daphnia in our study was 50 nanometers”, says Karin Mattsson.

Because zooplankton like Daphnia are also food for many other aquatic animals, the researchers wanted to study the effect of plastic particles higher up in the food chain. They found that fish that ate Daphnia containing nanoplastics experienced a change in their predatory behaviour and poor appetite. In several studies, researchers also discovered that the nanoparticles had the ability to cross biological barriers, such as the intestinal wall and brain.

“Although in our study we used much larger amounts of nanoplastic than those present in oceans today, we suspect that plastic particles may be accumulated inside the fish. This means that even low doses could ultimately have a negative effect”, says Karin Mattsson.

Plastic breaks down very slowly in nature, and once the microscopically small plastic particles reach lakes and oceans they are difficult to remove. Plastic particles also bind environmental toxins that can become part of the food chain when consumed accidentally.

“Our research indicates the need for more studies and increased caution in the use of nanoplastics”, she says.

Karin Mattsson is a physicist and her research project was produced in collaboration between the Centre for Environmental and Climate Research, the Division Biochemistry and Structural Biology and the Division of Aquatic Biology at Lund University. Karin Mattsson is also affiliated with NanoLund, where several studies are currently conducted to evaluate the safety of nanoparticles.

Here’s a link to and a citation for a paper published online in 2014 and in print in 2015,

Altered Behavior, Physiology, and Metabolism in Fish Exposed to Polystyrene Nanoparticles by Karin Mattsson, Mikael T. Ekvall, Lars-Anders Hansson, Sara Linse, Anders Malmendal, and Tommy Cedervall. Environ. Sci. Technol., 2015, 49 (1), pp 553–561 DOI: 10.1021/es5053655
Publication Date (Web): November 07, 2014

Copyright © 2014 American Chemical Society

More recently, Karin Mattson has published her PhD thesis on the topic (I believe it is written in Swedish).

The origins of gold and other precious metals

The link between this research and my side project on gold nanoparticles is a bit tenuous but this work on the origins for gold and other precious metals being found in the stars is so fascinating and I’m determined to find a connection.

An artist's impression of two neutron stars colliding. (Credit: Dana Berry / Skyworks Digital, Inc.) Courtesy: Kavli Foundation

An artist’s impression of two neutron stars colliding. (Credit: Dana Berry / Skyworks Digital, Inc.) Courtesy: Kavli Foundation

From a May 19, 2016 news item on,

The origin of many of the most precious elements on the periodic table, such as gold, silver and platinum, has perplexed scientists for more than six decades. Now a recent study has an answer, evocatively conveyed in the faint starlight from a distant dwarf galaxy.

In a roundtable discussion, published today [May 19, 2016?], The Kavli Foundation spoke to two of the researchers behind the discovery about why the source of these heavy elements, collectively called “r-process” elements, has been so hard to crack.

From the Spring 2016 Kavli Foundation webpage hosting the  “Galactic ‘Gold Mine’ Explains the Origin of Nature’s Heaviest Elements” Roundtable ,

RESEARCHERS HAVE SOLVED a 60-year-old mystery regarding the origin of the heaviest elements in nature, conveyed in the faint starlight from a distant dwarf galaxy.

Most of the chemical elements, composing everything from planets to paramecia, are forged by the nuclear furnaces in stars like the Sun. But the cosmic wellspring for a certain set of heavy, often valuable elements like gold, silver, lead and uranium, has long evaded scientists.

Astronomers studying a galaxy called Reticulum II have just discovered that its stars contain whopping amounts of these metals—collectively known as “r-process” elements (See “What is the R-Process?”). Of the 10 dwarf galaxies that have been similarly studied so far, only Reticulum II bears such strong chemical signatures. The finding suggests some unusual event took place billions of years ago that created ample amounts of heavy elements and then strew them throughout the galaxy’s reservoir of gas and dust. This r-process-enriched material then went on to form Reticulum II’s standout stars.

Based on the new study, from a team of researchers at the Kavli Institute at the Massachusetts Institute of Technology, the unusual event in Reticulum II was likely the collision of two, ultra-dense objects called neutron stars. Scientists have hypothesized for decades that these collisions could serve as a primary source for r-process elements, yet the idea had lacked solid observational evidence. Now armed with this information, scientists can further hope to retrace the histories of galaxies based on the contents of their stars, in effect conducting “stellar archeology.”

The Kavli Foundation recently spoke with three astrophysicists about how this discovery can unlock clues about galactic evolution as well as the abundances of certain elements on Earth we use for everything from jewelry-making to nuclear power generation. The participants were:

  • Alexander Ji – is a graduate student in physics at the Massachusetts Institute of Technology (MIT) and a member of the MIT Kavli Institute for Astrophysics and Space Research (MKI). He is lead author of a paper in Nature describing this discovery.
  • Anna Frebel – is the Silverman Family Career Development Assistant Professor in the Department of Physics at MIT and also a member of MKI. Frebel is Ji’s advisor and coauthored the Nature paper. Her work delves into the chemical and physical conditions of the early universe as conveyed by the oldest stars.
  • Enrico Ramirez-Ruiz – is a Professor of Astronomy and Astrophysics at the University of California, Santa Cruz. His research explores violent events in the universe, including the mergers of neutron stars and their role in generating r-process elements.

Here’s a link to and citation for Ji’s and Frebel’s paper about r-process elements in the stars,

R-process enrichment from a single event in an ancient dwarf galaxy by Alexander P. Ji, Anna Frebel, Anirudh Chiti, & Joshua D. Simon. Nature 531, 610–613 (31 March 2016) doi:10.1038/nature17425 Published online 21 March 2016

This paper is behind a paywall but you can read an edited transcript of the roundtable discussion on the Galactic ‘Gold Mine’ Explains the Origin of Nature’s Heaviest Elements webpage (keep scrolling past the introductory text).

As for my side project, Steep (2) on gold nanoparticles, that’s still in the planning stages but if there’s a way to include this information, I’ll do it.

Making rubber more rubbery for better condoms

A May 20, 2016 news item on Nanowerk announces some research on rubber from the University of Manchester (Note: A link has been removed),

In an article published in Carbon (“Graphene and water-based elastomers thin-film composites by dip-moulding”), Dr Aravind Vijayaraghavan and Dr Maria Iliut from Manchester have shown that adding a very small amount of graphene, the world’s thinnest and strongest material, to rubber films can increase both their strength and the elasticity by up to 50%. Thin rubber films are ubiquitous in daily life, used in everything from gloves to condoms.

A May 20, 2016 University of Manchester press release (also on EurekAlert), which originated the news item, provides more detail,

In their experiments, the scientists tested two kinds of rubbery materials – natural rubber, comprised of a material called polyisoprene, and a man-made rubber called polyurethane. To these, they added graphene of different kinds, amounts and size.

In most cases, it they observed that the resulting composite material could be stretched to a greater degree and with greater force before it broke. Indeed, adding just one tenth of one percent of graphene was all it took to make the rubber 50% stronger.

Dr Vijayaraghavan, who leads the Nano-functional Materials Group, explains “A composite is a material which contains two parts, a matrix which is soft and light and a filler which is strong. Taken together, you get something which is both light and strong. This is the principle behind carbon fibre composites used in sports cars, or Kevlar composites used in body armour.

“In this case, we have made a composite of rubber, which is soft and stretchy but fragile, with graphene and the resulting material is both stronger and stretchier.”

Dr Maria Iliut, a research associate in Dr Vijayaraghavan’s group, describes how this material is produced: “We use a form of graphene called graphene oxide, which unlike graphene is stable as a dispersion in water. The rubber materials are also in a form that is stable in water, allowing us to combine them before forming thin films with a process called dip moulding.”

“The important thing here is that because these films are so thin, we need a strengthening filler which is also very thin. Fortunately, graphene is both the thinnest and strongest material we know of.”

The project emerged from a call by the Bill & Melinda Gates Foundation, to develop a more desirable condom. [my Nov. 22, 2013 post features the grant announcement and Dr. Vijayaraghavan’s research plans] According to Dr Vijayaraghavan, this composite material has tremendous implications in daily life.

He adds “Our thinking was that if we could make the rubber used in condoms stronger and stretchier, then you could use that to make even thinner condoms which would feel better without breaking.

“Similar arguments can be made for using this material to make better gloves, sportswear, medical devices and so on. We are seeing considerable industrial interest in this area and we hope more companies will want to get involved in the commercial opportunities this research could create.”

Here’s a link to and a citation for the paper,

Graphene and water-based elastomers thin-film composites by dip-moulding by Maria Iliut, Claudio Silva, Scott Herrick, Mark McGlothlin, Aravind Vijayaraghavan. Carbon doi:10.1016/j.carbon.2016.05.032 Available online 14 May 2016

This paper is open access.