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Researchers at North Carolina State University have developed a new computational tool that allows users to conduct simulations of multi-functional magnetic nanoparticles in unprecedented detail. The advance paves the way for new work aimed at developing magnetic nanoparticles for use in applications from drug delivery to sensor technologies.

“Self-assembling magnetic nanoparticles, or MNPs, have a lot of desirable properties,” says Yaroslava Yingling, corresponding author of a paper on the work and a Distinguished Professor of Materials Science and Engineering at NC State. “But it has been challenging to study them, because computational models have struggled to account for all of the forces that can influence these materials. MNPs are subject to a complicated interplay between external magnetic fields and van der Waals, electrostatic, dipolar, steric, and hydrodynamic interactions.”

Many applications of MNPs require an understanding of how the nanoparticles will behave in complex environments, such as using MNPs to deliver a specific protein or drug molecule to a targeted cancer affected cell using external magnetic fields. In these cases, it is important to be able to accurately model how MNPs will respond to different chemical environments. Previous computational modeling techniques that looked at MNPs were unable to account for all of the chemical interactions MNPs experience in a given colloidal or biological environment, instead focusing primarily on physical interactions.

The human brain, fed on just the calorie input of a modest diet, easily outperforms state-of-the-art supercomputers powered by full-scale station energy inputs. The difference stems from the multiple states of brain processes versus the two binary states of digital processors, as well as the ability to store information without power consumption—non-volatile memory. These inefficiencies in today’s conventional computers have prompted great interest in developing synthetic synapses for use in computers that can mimic the way the brain works. Now, researchers at King’s College London, UK, report in ACS Nano Letters an array of nanorod devices that mimic the brain more closely than ever before. The devices may find applications in artificial neural networks.

Efforts to emulate biological synapses have revolved around types of memristors with different resistance states that act like memory. However, unlike the brain the devices reported so far have all needed a reverse polarity electrical voltage to reset them to the initial state. “In the brain a change in the chemical environment changes the output,” explains Anatoly Zayats, a professor at King’s College London who led the team behind the recent results. The King’s College London researchers have now been able to demonstrate this brain-like behavior in their synaptic synapses as well.

Zayats and team build an array of gold nanorods topped with a polymer junction (poly-L-histidine, PLH) to a metal contact. Either light or an electrical voltage can excite plasmons—collective oscillations of electrons. The plasmons release hot electrons into the PLH, gradually changing the chemistry of the polymer, and hence changing it to have different levels of conductivity or light emissivity. How the polymer changes depends on whether oxygen or hydrogen surrounds it. A chemically inert nitrogen chemical environment will preserve the state without any energy input required so that it acts as non-volatile memory.

The development of functional nanomaterials has been a major landmark in the history of materials science. Nanoparticles with diameters ranging from 5 to 500 nm have unprecedented properties, such as high catalytic activity, compared to their bulk material counterparts. Moreover, as particles become smaller, exotic quantum phenomena become more prominent. This has enabled scientists to produce materials and devices with characteristics that had been only dreamed of, especially in the fields of electronics, catalysis, and optics.

But what if we go smaller? Sub-nanoparticles (SNPs) with particle sizes of around 1 nm are now considered a new class of materials with distinct properties due to the predominance of quantum effects. The untapped potential of SNPs caught the attention of scientists from Tokyo Tech, who are currently undertaking the challenges arising in this mostly unexplored field. In a recent study published in the Journal of the American Chemical Society, a team of scientists from the Laboratory of Chemistry and Life Sciences, led by Dr. Takamasa Tsukamoto, demonstrated a novel molecular screening approach to find promising SNPs.

As one would expect, the synthesis of SNPs is plagued by technical difficulties, even more so for those containing multiple elements. Dr. Tsukamoto explains: “Even SNPs containing just two different elements have barely been investigated because producing a system of subnanometer scale requires fine control of the composition ratio and particle size with atomic precision.” However, this team of scientists had already developed a novel method by which SNPs could be made from different metal salts with extreme control over the total number of atoms and the proportion of each element.

The team noted that although other studies have been able to create nephrons and ureteric ducts from stem cells, these didn’t fully function as they would in real kidneys due to the absence of stromal cells, which are crucial for cell signaling. The team took embryonic stem cells from mice and induced these to differentiate into kidney-specific stromal cells, using a cocktail of chemicals meant to mimic those that would occur in vivo.

When they combined the stromal cells with nephron and ureteric bud cells (which they also created from stem cells), the result was a “kidney-like 3D tissue, consisting of extensively branched tubules and several other kidney-specific structures.”

According to the researchers, this is the most complex kidney structure that’s been generated from scratch in a lab. Though this study was done in mice, the team noted that it has already created the first two kidney components—nephron progenitors and ureteric buds—from human induced pluripotent stem cells (iPSCs). If they’re able to also create stromal cells from iPSCs, they said, “a similarly complex human kidney should be achievable.”

Picture yourself hovering over an alien city with billions of blinking lights of thousands of types, with the task of figuring out which ones are connected, which way the electricity flows and how that translates into nightlife. Welcome to the deep brain.

Even in an era rapidly becoming known as the heyday of neuroscience, tracing the biochemical signaling among billions of neurons deep in the brain has remained elusive and baffling.

A team of Stanford University researchers managed to map out one such connection, buried inside the brain of a living, moving mammal as they manipulated its behavior. The feat offers an unprecedented close-up of the genesis of social behavior on a cellular level, and could offer insights into psychiatric puzzles such as autism, depression and anxiety.

An analysis of radioactive chemicals in ice cores indicates one of the most powerful solar storms ever hit Earth around 7,176 B.C.

(Inside Science) — For a few nights more than 9,000 years ago, at a time when many of our ancestors were wearing animal skins, the northern skies would have been bright with flickering lights.

Telltale chemical isotopes in ancient ice cores suggest one of the most massive solar storms ever took place around 7,176 B.C., and it would have been noticed.

Continue reading “Ice holds evidence of ancient, massive solar storm” »

Scientists from the Max Planck Institute for Polymer Research, Paderborn University, and the University of Konstanz have succeeded in achieving a rare quantum state. They are the first to have demonstrated Wannier-Stark localization in a polycrystalline substance. Predicted around 80 years ago, the effect has only recently been proven — in a monocrystal. Until now, researchers assumed this localization to be possible only in such monocrystalline substances which are very complicated to produce. The new findings represent a breakthrough in the field of physics and could in future give rise to new optical modulators, for example, that can be used in information technologies based on light, among other things. The physicists have published their findings in the well-respected technical journal, Nature Communications.

Stronger and faster than lightning

The atoms of a crystal are arranged in a three-dimensional grid, held together by chemical bonds. These bonds can, however, be dissolved by very strong electric fields which displace atoms, even going so far as to introduce so much energy into the crystal that it is destroyed. This is what happens when lightning strikes and materials liquefy, vaporize or combust, for example. To demonstrate Wannier-Stark localization, the scientists’ experiments involved setting up electric fields of several million volts per centimeter, much stronger than the fields involved in lightning strikes. During this process, the electronic system of a solid — in this case, a polycrystal — is forced far from a state of equilibrium for a very short time. Wannier-Stark localization involves virtually shutting down some of the chemical bonds temporarily. This state can only be maintained for less than a picosecond — one millionth of one millionth of a second — without destroying the substance.

Hydrogen is already a key component of chemical industrial processes and in the steel industry. So making clean hydrogen to use in those industrial processes is critical to reducing carbon emissions, says Jake Stones at market research firm Independent Commodity Intelligence Services (ICIS).

But as an energy source itself, hydrogen’s big advantage is its versatility according to Sunita Satyapal, who oversees hydrogen fuel cell technology for the Department of Energy.

“It’s often called the Swiss Army knife of energy,” she says.

The world’s first demonstration device to produce 1,000 tons of gasoline per year from carbon dioxide (CO₂) hydrogenation has completed its technology evaluation and trial operation.

Located in the Zoucheng Industrial Park, Shandong province, China, the project has been jointly developed by the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) and the Zhuhai Futian Energy Technology company. The hydrogenation of CO₂ into liquid fuels and chemicals can not only realize the resource utilization of CO₂ but also facilitate the storage and transportation of renewable energy.

However, activation and selective conversion of CO₂ are challenging. A technology that can selectively produce energy-dense, value-added hydrocarbon fuels will provide a new route to promote the clean, low-carbon energy revolution.