Tag Archives: Japan

A new, stable open-shell carbon molecule from Oregon

This discovery could one day make organic solar cells more efficient than silicon ones. Researchers at the University of Oregon announced their discovery in a June 9, 2016 news item on ScienceDaily,

University of Oregon chemists have synthesized a stable and long-lasting carbon-based molecule that, they say, potentially could be applicable in solar cells and electronic devices.

The molecule changes its bonding patterns to a magnetic biradical state when heated; it then returns to a fully bonded non-magnetic closed state at room temperature. That transition, they report, can be done repeatedly without decomposition. It remains stable in the presence of both heat and oxygen.

A June 9, 2016 University of Oregon news release on EurekAlert, which originated the news item, provides more detail,

 

Biradical refers to organic compounds, known as open-shell molecules, that have two free-flowing, non-bonding electrons. Producing them using techniques to control their electron spin, and thus provide semiconducting properties, in a heated state has been hampered by instability since the first synthetic biradical hydrocarbon was made in 1907.

“Potentially our approach could help to make organic solar cells more efficient than silicon solar cells, but that’s probably far in the future,” said UO doctoral student Gabriel E. Rudebusch, the paper’s lead author. “Our synthesis is rapid and efficient. We easily can make a gram of this compound, which is very stable when exposed to oxygen and heat. This stability has been almost unheard of in the literature about biradical compounds.”

The four-step synthesis of the compound — diindenoanthracene, or DIAn — and how it held up when tested in superconducting materials were detailed in a proof-of-principle paper published online May 23 by the journal Nature Chemistry. The UO team collaborated with experts in Japan, Spain and Sweden.

The molecular framework for the new molecule involves the hydrocarbon anthracene, which has three linearly fused hexagonal benzene rings, in combination with two five-membered pentagonal rings.

“The big difference between our new molecule and a lot of other biradical molecules that have been produced is those five-membered rings,” said co-author Michael M. Haley, who holds the UO’s Richard M. and Patricia H. Noyes Professorship in Chemistry. “They have the inherent ability to accept electrons or give up electrons. This means DIAn can move both negative and positive charges, which is an essential property for useful devices such as transistors and solar cells. Also, we can heat up our molecule to 150 degrees Celsius, bring it back to room temperature and heat it up again, repeatedly, and we see no decomposition in its reaction to oxygen. The unique features of DIAn are essential if these molecules are to have a use in the real world.”

Haley’s lab is now seeking to develop derivatives of the new molecule to help move the technology forward into potential applications.

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

Diindeno-fusion of an anthracene as a design strategy for stable organic biradicals by Gabriel E. Rudebusch, José L. Zafra, Kjell Jorner, Kotaro Fukuda, Jonathan L. Marshall, Iratxe Arrechea-Marcos, Guzmán L. Espejo, Rocío Ponce Ortiz, Carlos J. Gómez-García, Lev N. Zakharov, Masayoshi Nakano, Henrik Ottosson, Juan Casado & Michael M. Haley. Nature Chemistry (2016)  doi:10.1038/nchem.2518 Published online 23 May 2016

This paper is behind a paywall.

There is another June 9, 2016 University of Oregon news release by Jim Barlow about this discovery. It covers much of the same material but focuses more closely on Rudebusch’s perspective.

New elements named (provisionally)

They say it’s provisionally but I suspect it would take an act of god for a change in the proposed names. From a June 8, 2016 blog posting (scroll down about 25% of the way) on the International Union of Pure and Applied Chemistry (IUPAC) website,

IUPAC is naming the four new elements nihonium, moscovium, tennessine, and oganesson

Following earlier reports that the claims for discovery of these elements have been fulfilled [1, 2], the discoverers have been invited to propose names and the following are now disclosed for public review:

  • Nihonium and symbol Nh, for the element 113,
  • Moscovium and symbol Mc, for the element 115,
  • Tennessine and symbol Ts, for the element 117, and
  • Oganesson and symbol Og, for the element 118.

The IUPAC Inorganic Chemistry Division has reviewed and considered these proposals and recommends these for acceptance. A five-month public review is now set, expiring 8 November 2016, prior to the formal approval by the IUPAC Council.

I can’t figure out how someone from the public might offer a comment about the names.

There’s more from the posting about what kinds of names are acceptable and how the names in this set of four were arrived at,

The guidelines for the naming the elements were recently revised [3] and shared with the discoverers to assist in their proposals. Keeping with tradition, newly discovered elements can be named after:
(a) a mythological concept or character (including an astronomical object),
(b) a mineral or similar substance,
(c) a place, or geographical region,
(d) a property of the element, or
(e) a scientist.
The names of all new elements in general would have an ending that reflects and maintains historical and chemical consistency. This would be in general “-ium” for elements belonging to groups 1-16, “-ine” for elements of group 17 and “-on” for elements of group 18. Finally, the names for new chemical elements in English should allow proper translation into other major languages.

For the element with atomic number 113 the discoverers at RIKEN Nishina Center for Accelerator-Based Science (Japan) proposed the name nihonium and the symbol Nh. Nihon is one of the two ways to say “Japan” in Japanese, and literally mean “the Land of Rising Sun”. The name is proposed to make a direct connection to the nation where the element was discovered. Element 113 is the first element to have been discovered in an Asian country. While presenting this proposal, the team headed by Professor Kosuke Morita pays homage to the trailblazing work by Masataka Ogawa done in 1908 surrounding the discovery of element 43. The team also hopes that pride and faith in science will displace the lost trust of those who suffered from the 2011 Fukushima nuclear disaster.

For the element with atomic number 115 the name proposed is moscovium with the symbol Mc and for element with atomic number 117, the name proposed is tennessine with the symbol Ts. These are in line with tradition honoring a place or geographical region and are proposed jointly by the discoverers at the Joint Institute for Nuclear Research, Dubna (Russia), Oak Ridge National Laboratory (USA), Vanderbilt University (USA) and Lawrence Livermore National Laboratory (USA).

Moscovium is in recognition of the Moscow region and honors the ancient Russian land that is the home of the Joint Institute for Nuclear Research, where the discovery experiments were conducted using the Dubna Gas-Filled Recoil Separator in combination with the heavy ion accelerator capabilities of the Flerov Laboratory of Nuclear Reactions.

Tennessine is in recognition of the contribution of the Tennessee region, including Oak Ridge National Laboratory, Vanderbilt University, and the University of Tennessee at Knoxville, to superheavy element research, including the production and chemical separation of unique actinide target materials for superheavy element synthesis at ORNL’s High Flux Isotope Reactor (HFIR) and Radiochemical Engineering Development Center (REDC).

For the element with atomic number 118 the collaborating teams of discoverers at the Joint Institute for Nuclear Research, Dubna (Russia) and Lawrence Livermore National Laboratory (USA) proposed the name oganesson and symbol Og. The proposal is in line with the tradition of honoring a scientist and recognizes Professor Yuri Oganessian (born 1933) for his pioneering contributions to transactinoid elements research. His many achievements include the discovery of superheavy elements and significant advances in the nuclear physics of superheavy nuclei including experimental evidence for the “island of stability”.

“It is a pleasure to see that specific places and names (country, state, city, and scientist) related to the new elements is recognized in these four names. Although these choices may perhaps be viewed by some as slightly self-indulgent, the names are completely in accordance with IUPAC rules”, commented Jan Reedijk, who corresponded with the various laboratories and invited the discoverers to make proposals. “In fact, I see it as thrilling to recognize that international collaborations were at the core of these discoveries and that these new names also make the discoveries somewhat tangible.”

So, let’s welcome Tennessine, Muscovium, Nihonium, and Oganesson to the table of periodic elements. I imagine Don Lehrer’s Elements Song will be updated soon. In the meantime we have this from ASAP Science, which includes the new elements under their placeholder names (when the addition was first publicized in January 2016. All of the placeholder names start with U,

Enjoy!

Canadian science petition and a science diplomacy event in Ottawa on June 21, 2016*

The Canadian science policy and science funding scene is hopping these days. Canada’s Minister of Science, Kirsty Duncan, announced a new review of federal funding for fundamental science on Monday, June 13, 2016 (see my June 15, 2016 post for more details and a brief critique of the panel) and now, there’s a new Parliamentary campaign for a science advisor and a Canadian Science Policy Centre event on science diplomacy.

Petition for a science advisor

Kennedy Stewart, Canadian Member of Parliament (Burnaby South) and NDP (New Democratic Party) Science Critic, has launched a campaign for independent science advice for the government. Here’s more from a June 15, 2016 announcement (received via email),

After years of muzzling and misuse of science by the Conservatives, our scientists need lasting protections in order to finally turn the page on the lost Harper decade.

I am writing to ask your support for a new campaign calling for an independent science advisor.

While I applaud the new Liberal government for their recent promises to support science, we have a long way to go to rebuild Canada’s reputation as a global knowledge leader. As NDP Science Critic, I continue to push for renewed research funding and measures to restore scientific integrity.

Canada badly needs a new science advisor to act as a public champion for research and evidence in Ottawa. Although the Trudeau government has committed to creating a Chief Science Officer, the Minister of Science – Dr. Kirsty Duncan – has yet to state whether or not the new officer will be given real independence and a mandate protected by law.

Today, we’re launching a new parliamentary petition calling for just that: https://petitions.parl.gc.ca/en/Petition/Sign/e-415

Can you add your name right now?

Canada’s last national science advisor lacked independence from the government and was easily eliminated in 2008 after the anti-science Harper Conservatives took power.

That’s why the Minister needs to build the new CSO to last and entrench the position in legislation. Rhetoric and half-measures aren’t good enough.

Please add your voice for public science by signing our petition to the Minister of Science.

Thank you for your support,

Breakfast session on science diplomacy

One June 21, 2016 the Canadian Science Policy Centre is presenting a breakfast session on Parliament Hill in Ottawa, (from an announcement received via email),

“Science Diplomacy in the 21st Century: The Potential for Tomorrow”
Remarks by Dr. Vaughan Turekian,
Science and Technology Adviser to Secretary of State John Kerry

Event Information
Tuesday, June 21, 2016, Room 238-S, Parliament Hill
7:30am – 8:00am – Continental Breakfast
8:00am – 8:10am – Opening Remarks, MP Terry Beech
8:10am – 8:45am – Dr. Vaughan Turekian Remarks and Q&A

Dr. Turekian’s visit comes during a pivotal time as Canada is undergoing fundamental changes in numerous policy directions surrounding international affairs. With Canada’s comeback on the world stage, there is great potential for science to play an integral role in the conduct of our foreign affairs.  The United States is currently one of the leaders in science diplomacy, and as such, listening to Dr.Turekian will provide a unique perspective from the best practices of science diplomacy in the US.

Actually, Dr. Turekian’s visit comes before a North American Summit being held in Ottawa on June 29, 2016 and which has already taken a scientific turn. From a June 16, 2016 news item on phys.org,

Some 200 intellectuals, scientists and artists from around the world urged the leaders of Mexico, the United States and Canada on Wednesday to save North America’s endangered migratory Monarch butterfly.

US novelist Paul Auster, environmental activist Robert F. Kennedy Jr., Canadian poet [Canadian media usually describe her as a writer] Margaret Atwood, British writer Ali Smith and India’s women’s and children’s minister Maneka Sanjay Gandhi were among the signatories of an open letter to the three leaders.

US President Barack Obama, Canadian Prime Minister Justin Trudeau and Mexican President Enrique Pena Nieto will hold a North American summit in Ottawa on June 29 [2016].

The letter by the so-called Group of 100 calls on the three leaders to “take swift and energetic actions to preserve the Monarch’s migratory phenomenon” when they meet this month.

In 1996-1997, the butterflies covered 18.2 hectares (45 acres) of land in Mexico’s central mountains.

It fell to 0.67 hectares in 2013-2014 but rose to 4 hectares this year. Their population is measured by the territory they cover.

They usually arrive in Mexico between late October and early November and head back north in March.

Given this turn of events, I wonder how Turekian, given that he’s held his current position for less than a year, might (or might not) approach the question of Monarch butterflies and diplomacy.

I did a little research about Turekian and found this Sept. 10, 2016 news release announcing his appointment as the Science and Technology Adviser to the US Secretary of State,

On September 8, Dr. Vaughan Turekian, formerly the Chief International Officer at The American Association for the Advancement of Science (AAAS), was named the 5th Science and Technology Adviser to the Secretary of State. In this capacity, Dr. Turekian will advise the Secretary of State and the Under Secretary for Economic Growth, Energy, and the Environment on international environment, science, technology, and health matters affecting the foreign policy of the United States. Dr. Turekian will draw upon his background in atmospheric chemistry and extensive policy experience to promote science, technology, and engineering as integral components of U.S. diplomacy.

Dr. Turekian brings both technical expertise and 14 years of policy experience to the position. As former Chief International Officer for The American Association for the Advancement of Science (AAAS) and Director of AAAS’s Center for Science Diplomacy, Dr. Turekian worked to build bridges between nations based on shared scientific goals, placing special emphasis on regions where traditional political relationships are strained or do not exist. As Editor-in-Chief of Science & Diplomacy, an online quarterly publication, Dr. Turekian published original policy pieces that have served to inform international science policy recommendations. Prior to his work at AAAS, Turekian worked at the State Department as Special Assistant and Adviser to the Under Secretary for Global Affairs on issues related to sustainable development, climate change, environment, energy, science, technology, and health and as a Program Director for the Committee on Global Change Research at the National Academy of Sciences where he was study director for a White House report on climate change science.

Turekian’s last editorial for Science & Diplomacy dated June 30, 2015 features a title (Evolving Institutions for Twenty-First Century [Science] Diplomacy) bearing a resemblance to the title for his talk in Ottawa and perhaps it provides a preview (spoilers),

Over the recent decade, its treatment of science and technology issues has increased substantially, with a number of cover stories focused on topics that bridge science, technology, and foreign affairs. This thought leadership reflects a broader shift in thinking within institutions throughout the world about the importance of better integrating the communities of science and diplomacy in novel ways.

In May, a high-level committee convened by Japan’s minister of foreign affairs released fifteen recommendations for how Japan could better incorporate its scientific and technological expertise into its foreign policy. While many of the recommendations were to be predicted, including the establishment of the position of science adviser to the foreign minister, the breadth of the recommendations highlighted numerous new ways Japan could leverage science to meet its foreign policy objectives. The report itself marks a turning point for an institution looking to upgrade its ability to meet and shape the challenges of this still young century.

On the other side of the Pacific, the U.S. National Academy of Sciences released its own assessment of science in the U.S. Department of State. Their report, “Diplomacy for the 21st Century: Embedding a Culture of Science and Technology Throughout the Department of State,” builds on its landmark 1999 report, which, among other things, established the position of science and technology adviser to the secretary of state. The twenty-seven recommendations in the new report are wide ranging, but as a whole speak to the fact that while one of the oldest U.S. institutions of government has made much progress toward becoming more scientifically and technologically literate, there are many more steps that could be taken to leverage science and technology as a key element of U.S. foreign policy.

These two recent reports highlight the importance of foreign ministries as vital instruments of science diplomacy. These agencies of foreign affairs, like their counterparts around the world, are often viewed as conservative and somewhat inflexible institutions focused on stability rather than transformation. However, they are adjusting to a world in which developments in science and technology move rapidly and affect relationships and interactions at bilateral, regional, and global scales.

At the same time that some traditional national instruments of diplomacy are evolving to better incorporate science, international science institutions are also evolving to meet the diplomatic and foreign policy drivers of this more technical century. …

It’s an interesting read and I’m glad to see the mention of Japan in his article. I’d like to see Canadian science advice and policy initiatives take more notice of the rest of the world rather than focusing almost solely on what’s happening in the US and Great Britain (see my June 15, 2016 post for an example of what I mean). On another note, it was disconcerting to find out that Turekian believes that we are only now moving past the Cold War politics of the past.

Unfortunately for anyone wanting to attend the talk, ticket sales have ended even though they were supposed to be open until June 17, 2016. And, there doesn’t seem to be a wait list.

You may want to try arriving at the door and hoping that people have cancelled or fail to arrive therefore acquiring a ticket. Should you be an MP (Member of Parliament), Senator, or guest of the Canadian Science Policy Conference, you get a free ticket. Should you be anyone else, expect to pay $15, assuming no one is attempting to scalp (sell one for more than it cost) these tickets.

*’ … on June’ in headline changed to ‘ … on June 21, 2016’ on June 17, 2016.

AI (artificial intelligence) and logical dialogue in Japanese

Hitachi Corporation has been exciting some interest with its announcement of the latest iteration of its artificial intelligence programme’s and its new ability to speak Japanese (from a June 5, 2016 news item on Nanotechnology Now),

Today, the social landscape changes rapidly and customer needs are becoming increasingly diversified. Companies are expected to continuously create new services and values. Further, driven by recent advancements in information & telecommunication and analytics technologies, interest is growing in technology that can extract valuable insight from big data which is generated on a daily basis.

Hitachi has been developing a basic AI technology that analyzes huge volumes of English text data and presents opinions in English to help enterprises make business decisions. The original technology required rules of grammar specific to the English language to be programmed, to extract sentences representing reasons and grounds for opinions. This process represented a hurdle in applying system to Japanese or any other language as it required dedicated programs correlated to the linguistic rules of the target language.

By applying deep learning, this issue was eliminated thus enabling the new technology to recognize sentences that have high probability of being reasons and grounds without relying on linguistic rules. More specifically, the AI system is presented with sentences which represent reasons and grounds extracted from thousands of articles. Learning from the rules and patterns, the system becomes discriminating of sentences which represent reasons and grounds in new articles. Hitachi added an attention mechanism” which support deep learning to estimate which words and phrases are worthy of attention in texts like news articles and research reports. The “attention mechanism” helps the system to grasp the points that require attention, including words and phrases related to topics and values. This method enables the system to distinguish sentences which have a high probability of being reasons and grounds from text data in any language.

They have plans for this technology,

The technology developed will be core technology in achieving a multi-lingual AI system capable of offering opinion. Hitachi will pursue further research to realize AI systems supporting business decision making by enterprises worldwide.

The June 2, 2016 Hitachi news release which originated the news item can be found here.

The birth of carbon nanotubes (CNTs): a history

There is a comprehensive history of the carbon nanotube stretching back to prehistory and forward to recent times in a June 3, 2016 Nanowerk Spotlight article by C.K. Nisha and Yashwant Mahajan of the Center of Knowledge Management of Nanoscience & Technology (CKMNT) in India. The authors provide an introduction explaining the importance of CNTs,

Carbon nanotubes (CNTs) have been acknowledged as the material of the 21st century. They possess unique combination of extraordinary mechanical, electronic, transport, electrical and optical, properties and nanoscale sizes making them suitable for a variety of applications ranging from engineering, electronics, optoelectronics, photonics, space, defence industry, medicine, molecular and biological systems and so on and so forth. Worldwide demand for CNTs is increasing at a rapid pace as applications for the material are being matured.

According to MarketsandMarkets (M&M), the global market for carbon nanotubes in 2015 was worth about $2.26 billion1; an increase of 45% from 2009 (i.e. ~ $ 1.24 billion). This was due to the growing potential of CNTs in electronics, plastics and energy storage applications and the projected market of CNTs is expected to be around $ 5.64 billion in 2020.

In view of the scientific and technological potential of CNTs, it is of immense importance to know who should be credited for their discovery. In the present article, we have made an attempt to give a glimpse into the discovery and early history of this fascinating material for our readers. Thousands of papers are being published every year on CNTs or related areas and most of these papers give credit for the discovery of CNTs to Sumio Iijima of NEC Corporation, Japan, who, in 1991, published a ground-breaking paper in Nature reporting the discovery of multi-walled carbon nanotubes (MWCNTs)2. This paper has been cited over 27,105 times in the literature (as on January 12, 2016, based on Scopus database). This discovery by Iijima has triggered an avalanche of scientific publications and catapulted CNTs onto the global scientific stage.

Nisha and Mahajan then prepare to take us back in time,

In a guest editorial for the journal Carbon, Marc Monthioux and Vladimir L. Kuznetsov3 have tried to clear the air by describing the chronological events that led to the discovery of carbon nanotubes. As one delves deeper into the history of carbon nanotubes, it becomes more apparent that the origin of CNTs could be even pre-historic in nature.

Recently, Ponomarchuk et al from Russia have reported the presence micro and nano carbon tubes in igneous rocks formed about 250 million years ago4-7. They suggested the possibility of formation of carbon nanotubes during the magmatic processes. It is presumed that the migration of hydrocarbon fluids through the residual melt of the rock groundmass created gas-saturated areas (mostly CH4, CO2, CO) in which condensation and decomposition of hydrocarbon in presence of metal elements resulted in the formation of micro and sub-micron carbon tubes.

Another most compelling evidence of pre-historic naturally occurring carbon nanotubes (MWCNTs) is based on the TEM studies carried out by Esquivel and Murr8 that analyzed 10,000-year-old Greenland ice core samples and it was suggested that probably they could have been formed during combustion of natural gas/methane during natural processes.

However, the validity of this evidence is questionable owing to the lack of clear high-resolution TEM images, high-quality diffraction patterns or Raman spectroscopy data. In addition, [an]other interesting possibility is that the carbon nanotubes could have been directly formed by the transformation of naturally occurring C60 fullerenes in nature without the assistance of man, given the right conditions prevail. Suchanek et al.,9 have actually demonstrated this thesis, under the laboratory environment, by transforming C60 fullerenes into CNTs under hydrothermal conditions.

There is a large body of evidence in literature about the existence of naturally occurring fullerenes in nature, e.g., coal, carboneous rocks, interstellar media, etc. Since the above experiments were conducted under the simulated geological environment, their results imply that CNTs may form in natural hydrothermal environment.

This hypothesis was further corroborated by Velasco-Santos and co-workers10, when they reported the presence of CNTs in a coal–petroleum mix obtained from an actual oil well, identified by the PEMEX (the Mexican Petroleum Company) as P1, which is located in Mexico’s southeast shore. TEM studies revealed that the coal-petroleum mix contained predominantly end-capped CNTs that are nearly 2 µm long with outer diameter varying between few to several tenths of nanometers.

There’s another study supporting the notion that carbon nanotubes may be formed naturally,

In yet another study, researchers from Germany11 have synthesized carbon nanotubes using igneous rock from Mount Etna lava as both support and catalyst. The naturally occurring iron oxide particles present in Etna lava rock make it an ideal material for growing and immobilizing nanocarbons.

When a mixture of ethylene and hydrogen were passed over the pulverized rocks reduced in a hydrogen atmosphere at 700°C, the iron particles catalyzed the decomposition of ethylene to elemental carbon, which gets deposited on the lava rock in the form of tiny tubes and fibers.
This study showed that if a carbon source is available, CNTs/CNFs can grow on a mineral at moderate temperatures, which directs towards the possibilities of carbon nanotube formation in active suboceanic volcanos or even in interstellar space where methane, atomic hydrogen, carbon oxides, and metallic iron are present.

This fascinating and informative piece was originally published in the January 2016 edition of Nanotech Insights (CKMNT newsletter; scroll down) and can be found there although it may be more easily accessible as the June 3, 2016 Nanowerk Spotlight article where it extends over five (Nanowerk) pages and has a number of embedded images along with an extensive list of references at the end.

Enjoy!

pH dependent nanoparticle-based contrast agent for MRIs (magnetic resonance images)

This news about a safer and more effective contrast agent for MRIs (magnetic resonance images) developed by Japanese scientists come from a June 6, 2016 article by Heather Zeiger on phys.org. First some explanations,

Magnetic resonance imaging relies on the excitation and subsequent relaxation of protons. In clinical MRI studies, the signal is determined by the relaxation time of the hydrogen protons in water. To get a stronger signal, scientists can use contrast agents to shorten the relaxation time of the protons.

MRI is non-invasive and does not involve radiation, making it a safe diagnostic tool. However, its weak signal makes tumor detection difficult. The ideal contrast agent would select for malignant tumors, making its location and diagnosis much more obvious.

Nanoparticle contrast agents have been of interested because nanoparticles can be functionalized and, as in this study, can contain various metals. Researchers have attempted to functionalize nanoparticles with ligands that attach to chemical factors on the surface of cancer cells. However, cancer cells tend to be compositionally heterogeneous, leading some researchers to look for nanoparticles that respond to differences in pH or redox potential compared to normal cells.

Now for the research,

Researchers from the University of Tokyo, Tokyo Institute of Technology, Kawasaki Institute of Industry Promotion, and the Japan Agency for Quantum and Radiological Science and Technology have developed a contrast agent from calcium phosphate-based nanoparticles that release a manganese ion an acidic environment. …

Peng Mi, Daisuke Kokuryo, Horacio Cabral, Hailiang Wu, Yasuko Terada, Tsuneo Saga, Ichio Aoki, Nobuhiro Nishiyama, and Kazunori Kataoka developed a contrast agent that is comprised of Mn2+– doped CaP nanoparticles with a PEG shell. They reasoned that using CaP nanoparticles, which are known to be pH sensitive, would allow the targeted release of Mn2+ ions in the tumor microenvironment. The tumor microenvironment tends to have a lower pH than the normal regions to rapid cell metabolism in an oxygen-depleted environment. Manganese ions were tested because they are paramagnetic, which makes for a good contrast agent. They also bind to proteins creating a slowly rotating manganese-protein system that results in sharp contrast enhancement.

These results were promising, so Peng Mi, et al. then tested whether the CaPMnPEG contrast agent worked in solid tumors. Because Mn2+ remains confined within the nanoparticle matrix at physiological pH, CaPMnPEG demonstrate a much lower toxicity [emphasis mine] compared to MnCl2. MRI studies showed a tumor-to-normal contrast of 131% after 30 minute, which is much higher than Gd-DTPA [emphasis mine], a clinically approved contrast agent. After an hour, the tumor-to-normal ratio was 160% and remained around 170% for several hours.

Three-dimensional MRI studies of solid tumors showed that without the addition of CaPMnPEG, only blood vessels were visible. However, upon adding CaPMnPEG, the tumor was easily distinguishable. Additionally, there is evidence that excess Mn2+ leaves the plasma after an hour. The contrast signal remained strong for several hours indicating that protein binding rather than Mn2+ concentration is important for signal enhancement.

Finally, tests with metastatic tumors in the liver (C26 colon cancer cells) showed that CaPMnPEG works well in solid organ analysis and is highly sensitive to detecting millimeter-sized micrometastasis [emphasis mine]. Unlike other contrast agents used in the clinic, CaPMnPEG provided a contrast signal that lasted for several hours after injection. After an hour, the signal was enhanced by 25% and after two hours, the signal was enhanced by 39%.

This is exciting stuff. Bravo to the researchers!

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

A pH-activatable nanoparticle with signal-amplification capabilities for non-invasive imaging of tumour malignancy by Peng Mi, Daisuke Kokuryo, Horacio Cabral, Hailiang Wu, Yasuko Terada, Tsuneo Saga, Ichio Aoki, Nobuhiro Nishiyama, & Kazunori Kataoka. Nature Nanotechnology (2016) doi:10.1038/nnano.2016.72 Published online 16 May 2016

This paper is behind a paywall.

Watching artificial nanofibres self-sort in real-time

A May 31, 2016 news item on phys.org describes research on self-assembling fibres at Kyoto University (Japan) by referencing the ancient Greek mythological figure, Psyche,

The Greek goddess Psyche borrowed help from ants to sort a room full of different grains. Cells, on the other hand, do something similar without Olympian assistance, as they organize molecules into robust, functional fibers. Now scientists are able to see self-sorting phenomena happen in real time with artificial molecules.

The achievement, reported in Nature Chemistry, elucidates how two different types of nanofibers sort themselves into organized structures under artificial conditions.

“Basic cellular structures, such as actin filaments, come into being through the autonomous self-sorting of individual molecules, even though a tremendous variety of proteins and small molecules are present inside the cell,” says lead author Hajime Shigemitsu, a researcher in Itaru Hamachi’s lab at Kyoto University.

A May 30, 2016 Kyoto University news release (also on EurekAlert), which originated the news item, expands on the theme,

“Imagine a box filled with an assortment of building blocks — it’s as if the same type of blocks started sorting themselves into neat bundles all on their own. In living cells, such phenomena always happen, enabling accurate self-assembling of proteins, which is essential for cell functions.”

“If we are able to control self-sorting with artificial molecules, we can work toward developing intelligent, next-generation biomimics that possess the flexibility and diversity of functions that exist in a living cell.”

Study co-author Ryou Kubota explains that previous studies have already made artificial molecules build themselves into fibers — but only when there was one type of molecule around. Having a jumble of types, on the other hand, made the molecules confused.

“The difficulty in inducing self-assembly with artificial molecules is that they don’t recognize the same type of molecule, unlike molecules in the natural world. Different types of artificial molecules interact with each other and make an unsorted cluster.”

From a database of structural analyses, Hamachi and colleagues discovered a combination of nanofibers — namely a peptide-based and lipid-based hydrogelator — that would make sorted fibers without mixing with the other. They then tethered the fibers with fluorescent probes; with a type of microscope typically used in cell imaging, the team was able to observe directly and in real-time how the artificial molecules sorted themselves.

“Ultimately, this finding could help develop new materials that respond dynamically to different environments and stimuli,” elaborates Hamachi. “This insight is not only useful for materials science, but may also provide useful clues for understanding self-organization in cells.”

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

In situ real-time imaging of self-sorted supramolecular nanofibres by Shoji Onogi, Hajime Shigemitsu, Tatsuyuki Yoshii, Tatsuya Tanida, Masato Ikeda, Ryou Kubota, & Itaru Hamachi. Nature Chemistry (2016) doi:10.1038/nchem.2526 Published online 30 May 2016

This paper is behind a paywall bu the researchers have made a video of the self-sorting proteins freely available,

Measuring the van der Waals forces between individual atoms for the first time

A May 13, 2016 news item on Nanowerk heralds the first time measuring the van der Waals forces between individual atoms,

Physicists at the Swiss Nanoscience Institute and the University of Basel have succeeded in measuring the very weak van der Waals forces between individual atoms for the first time. To do this, they fixed individual noble gas atoms within a molecular network and determined the interactions with a single xenon atom that they had positioned at the tip of an atomic force microscope. As expected, the forces varied according to the distance between the two atoms; but, in some cases, the forces were several times larger than theoretically calculated.

A May 13, 2016 University of Basel press release (also on EurekAlert), which originated the news item, provides an explanation of van der Waals forces (the most comprehensive I’ve seen) and technical details about how the research was conducted,

Van der Waals forces act between non-polar atoms and molecules. Although they are very weak in comparison to chemical bonds, they are hugely significant in nature. They play an important role in all processes relating to cohesion, adhesion, friction or condensation and are, for example, essential for a gecko’s climbing skills.

Van der Waals interactions arise due to a temporary redistribution of electrons in the atoms and molecules. This results in the occasional formation of dipoles, which in turn induce a redistribution of electrons in closely neighboring molecules. Due to the formation of dipoles, the two molecules experience a mutual attraction, which is referred to as a van der Waals interaction. This only exists temporarily but is repeatedly re-formed. The individual forces are the weakest binding forces that exist in nature, but they add up to reach magnitudes that we can perceive very clearly on the macroscopic scale – as in the example of the gecko.

Fixed within the nano-beaker

To measure the van der Waals forces, scientists in Basel used a low-temperature atomic force microscope with a single xenon atom on the tip. They then fixed the individual argon, krypton and xenon atoms in a molecular network. This network, which is self-organizing under certain experimental conditions, contains so-called nano-beakers of copper atoms in which the noble gas atoms are held in place like a bird egg. Only with this experimental set-up is it possible to measure the tiny forces between microscope tip and noble gas atom, as a pure metal surface would allow the noble gas atoms to slide around.

Compared with theory

The researchers compared the measured forces with calculated values and displayed them graphically. As expected from the theoretical calculations, the measured forces fell dramatically as the distance between the atoms increased. While there was good agreement between measured and calculated curve shapes for all of the noble gases analyzed, the absolute measured forces were larger than had been expected from calculations according to the standard model. Above all for xenon, the measured forces were larger than the calculated values by a factor of up to two.

The scientists are working on the assumption that, even in the noble gases, charge transfer occurs and therefore weak covalent bonds are occasionally formed, which would explain the higher values.

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

Van der Waals interactions and the limits of isolated atom models at interfaces by Shigeki Kawai, Adam S. Foster, Torbjörn Björkman, Sylwia Nowakowska, Jonas Björk, Filippo Federici Canova, Lutz H. Gade, Thomas A. Jung, & Ernst Meyer. Nature Communications 7, Article number: 11559  doi:10.1038/ncomms11559 Published 13 May 2016

This is an open access paper.

Ingestible origami robot gets one step closer

Fiction, more or less seriously, has been exploring the idea of ingestible, tiny robots that can enter the human body for decades (Fantastic Voyage and Innerspace are two movie examples). The concept is coming closer to being realized as per a May 12, 2016 news item on phys.org,

In experiments involving a simulation of the human esophagus and stomach, researchers at MIT [Massachusetts Institute of Technology], the University of Sheffield, and the Tokyo Institute of Technology have demonstrated a tiny origami robot that can unfold itself from a swallowed capsule and, steered by external magnetic fields, crawl across the stomach wall to remove a swallowed button battery or patch a wound.

A May 12, 2016 MIT news release (also on EurekAlert), which originated the news item, provides some fascinating depth to this story (Note: Links have been removed),

The new work, which the researchers are presenting this week at the International Conference on Robotics and Automation, builds on a long sequence of papers on origami robots from the research group of Daniela Rus, the Andrew and Erna Viterbi Professor in MIT’s Department of Electrical Engineering and Computer Science.

“It’s really exciting to see our small origami robots doing something with potential important applications to health care,” says Rus, who also directs MIT’s Computer Science and Artificial Intelligence Laboratory (CSAIL). “For applications inside the body, we need a small, controllable, untethered robot system. It’s really difficult to control and place a robot inside the body if the robot is attached to a tether.”

Although the new robot is a successor to one reported at the same conference last year, the design of its body is significantly different. Like its predecessor, it can propel itself using what’s called a “stick-slip” motion, in which its appendages stick to a surface through friction when it executes a move, but slip free again when its body flexes to change its weight distribution.

Also like its predecessor — and like several other origami robots from the Rus group — the new robot consists of two layers of structural material sandwiching a material that shrinks when heated. A pattern of slits in the outer layers determines how the robot will fold when the middle layer contracts.

Material difference

The robot’s envisioned use also dictated a host of structural modifications. “Stick-slip only works when, one, the robot is small enough and, two, the robot is stiff enough,” says Guitron [Steven Guitron, a graduate student in mechanical engineering]. “With the original Mylar design, it was much stiffer than the new design, which is based on a biocompatible material.”

To compensate for the biocompatible material’s relative malleability, the researchers had to come up with a design that required fewer slits. At the same time, the robot’s folds increase its stiffness along certain axes.

But because the stomach is filled with fluids, the robot doesn’t rely entirely on stick-slip motion. “In our calculation, 20 percent of forward motion is by propelling water — thrust — and 80 percent is by stick-slip motion,” says Miyashita [Shuhei Miyashita, who was a postdoc at CSAIL when the work was done and is now a lecturer in electronics at the University of York, England]. “In this regard, we actively introduced and applied the concept and characteristics of the fin to the body design, which you can see in the relatively flat design.”

It also had to be possible to compress the robot enough that it could fit inside a capsule for swallowing; similarly, when the capsule dissolved, the forces acting on the robot had to be strong enough to cause it to fully unfold. Through a design process that Guitron describes as “mostly trial and error,” the researchers arrived at a rectangular robot with accordion folds perpendicular to its long axis and pinched corners that act as points of traction.

In the center of one of the forward accordion folds is a permanent magnet that responds to changing magnetic fields outside the body, which control the robot’s motion. The forces applied to the robot are principally rotational. A quick rotation will make it spin in place, but a slower rotation will cause it to pivot around one of its fixed feet. In the researchers’ experiments, the robot uses the same magnet to pick up the button battery.

Porcine precedents

The researchers tested about a dozen different possibilities for the structural material before settling on the type of dried pig intestine used in sausage casings. “We spent a lot of time at Asian markets and the Chinatown market looking for materials,” Li [Shuguang Li, a CSAIL postdoc] says. The shrinking layer is a biodegradable shrink wrap called Biolefin.

To design their synthetic stomach, the researchers bought a pig stomach and tested its mechanical properties. Their model is an open cross-section of the stomach and esophagus, molded from a silicone rubber with the same mechanical profile. A mixture of water and lemon juice simulates the acidic fluids in the stomach.

Every year, 3,500 swallowed button batteries are reported in the U.S. alone. Frequently, the batteries are digested normally, but if they come into prolonged contact with the tissue of the esophagus or stomach, they can cause an electric current that produces hydroxide, which burns the tissue. Miyashita employed a clever strategy to convince Rus that the removal of swallowed button batteries and the treatment of consequent wounds was a compelling application of their origami robot.

“Shuhei bought a piece of ham, and he put the battery on the ham,” Rus says. [emphasis mine] “Within half an hour, the battery was fully submerged in the ham. So that made me realize that, yes, this is important. If you have a battery in your body, you really want it out as soon as possible.”

“This concept is both highly creative and highly practical, and it addresses a clinical need in an elegant way,” says Bradley Nelson, a professor of robotics at the Swiss Federal Institute of Technology Zurich. “It is one of the most convincing applications of origami robots that I have seen.”

I wonder if they ate the ham afterwards.

Happily, MIT has produced a video featuring this ingestible, origami robot,

Finally, this team has a couple more members than the previously mentioned Rus, Miyashita, and Li,

…  Kazuhiro Yoshida of Tokyo Institute of Technology, who was visiting MIT on sabbatical when the work was done; and Dana Damian of the University of Sheffield, in England.

As Rus notes in the video, the next step will be in vivo (animal) studies.

Nanotechnology and vinyl records

A Taipei Times April 17, 2016 article by Chang Chung-yi and Jake Chung announces,

… a recent technological breakthrough in the production of vinyl records might lead to a resurgence in their popularity, especially for audiophiles.

The Taiwan branch of Japanese company Ulvac unveiled samples of its vinyl records — coated in nano-scale molybdenum — at the Hi-End Audio Show in Kaohsiung that opened on Thursday and is to run through today, with more than 200 international brands displaying products at its 80 stalls.

Ulvac demonstrated the technology’s ability to fix common problems that plague vinyl records, such as scratching, poor heat conductivity and susceptibility to static electricity.

Ulvac staff said that the coating helps harden the polyvinyl chloride (PVC) material that records are made of and prevents it from being easily damaged, adding that the coating also allows for more refined sound quality.

Local media reported that the coating was developed by Ulvac Taiwan vice chief executive officer Clare Wei (魏雲祥), who started listening to vinyl records last year.

After discovering the problems associated with the PVC used in the production of records, Wei spent more than NT$150 million (US$4.64 million) on laboratories, equipment and personnel to try to apply the nano-scale coating material on vinyl, the Chinese-language United Daily News reported.

According to one expert, the technology for producing records hadn’t changed since the 1940’s.