and understand the intrinsic spin of electrons to advance nanoscale electronics is hampered by how hard it is to measure tiny, fast magnetic devices.
assistant professor of applied and engineering physics, detail this new way to directly measure magnetic moments and how it may be used to break fundamental limits of spatial resolution that are imposed in purely optical magnetic measurements.
if perfected, could lead to a novel tabletop magnetic measurement technique and new, nanoscale electronic devices based on electrical spin, rather than charge.
is detailed in the journal Nature Communications("Toward a table-top microscope for nanoscale magnetic imaging using picosecond thermal gradients").
An emerging field called spintronics explores the idea of using electron spin to control and store information using very low power. echnologies like nonvolatile magnetic memory could result with the broad understanding and application of electron spin.
Spintronics, the subject of the 2007 Nobel prize in Physics, is already impacting traditional electronics, which is based on the control of electron charge rather than spin. irect imaging is really hard to do,
Wee talking about nanometers and picoseconds. Scientists have been unable to directly image magnetic motion in nanoscale spintronic devices without hugely expensive X-ray sources at national facilities.
In their own labs, the best they could do was infer magnetic properties from electrical measurements.
graduate student in the field of applied physics. t an exciting area to start looking at
such as fabricating gold antennae to excite thermal excitations confined to nanoscale dimensions o
#Simple detection of magnetic skyrmions At present, tiny magnetic whirls so called skyrmions are discussed as promising candidates for bits in future robust and compact data storage devices.
At the University of Hamburg these exotic magnetic structures were recently found to exist in ultrathin magnetic layers and multilayers,
similar to the ones used in current hard-disk drives and magnetic sensors. However, up to now an additional magnet was necessary for a read-out of skyrmions.
Now researchers from the University of Hamburg and the Christian-Albrechts-Universität in Kiel have demonstrated that skyrmions can be detected much more easily because of a drastic change of the electrical resistance in these magnetic whirls("Electrical detection of magnetic skyrmions by tunnelling non-collinear magnetoresistance".
"For future data storage concepts this promises a significant simplification in terms of fabrication and operation. Stable whirls in magnetic materials (see figure) were predicted over 25 years ago,
but the experimental realization was achieved only recently. The discovery of such skyrmions in thin magnetic films and multilayers, already used in today technology,
and the possibility to move these skyrmions at very low electrical current densities, has opened the perspective to use them as bits in novel data storage devices.
Up to now individual magnetic whirls were detected either by electron microscopy or by the resistance change in a tunnel contact with a magnetic probe.
Employing a scanning tunneling microscope researchers of the University of Hamburg were now able to demonstrate that the resistance changes also
when a nonmagnetic metal is used in such a measurement. n our experiment we can move a metallic tip over a surface with atomic-scale precision,
and in this way we can measure the resistance at different positions in a skyrmionsays Christian Hanneken, a Phd student in the group of Prof.
Roland Wiesendanger. This enables the proof for the locally varying resistance within the magnetic whirl. e found a resistance change of up to 100,
In collaboration with theoretical physicists from the University of Kiel the researchers were able to identify the origin of the resistance change in the magnetic whirl:
Stefan Heinze from the University of Kiel. When the electrons are travelling through a magnetic whirl,
leading to a local resistance change of the material. e were able to understand this effect by performing extensive numerical computer simulations of the electronic properties
and developed a simple model for this effect as the Phd student Fabian Otte explains.
The possibility to use arbitrary metallic electrodes significantly simplifies the fabrication and operation of such novel storage devices
#Even if imprisoned inside a crystal, molecules can still move X-ray crystallography reveals the three-dimensional structure of a molecule,
thus making it possible to understand how it works and potentially use this knowledge to subsequently modulate its activity, especially for therapeutic or biotechnological purposes.
For the first time, a study has shown that residual movements continue to animate proteins inside a crystal and that this movement"blurs"the structures obtained via crystallography.
The study stresses that the more these residual movements are restricted, the better the crystalline order.
That is why molecules consisting of the most compact crystals generally make it possible to obtain structures of better quality.
This research combines crystallography nuclear magnetic resonance (NMR) and simulation and is the result of an international cooperation involving researchers from the Institute of Structural biology (ISB, CEA/CNRS/Joseph Fourier University) in Grenoble, France, Purdue University, USA,
and the Institute of Complex Systems (ICS-6: Structural Biochemistry) at Forschungszentrum Jülich in Germany.
The results were published in Nature Communications. X-ray crystallography is the most prolific method for determining protein structures.
The quality of a crystallographic structure depends on the"degree of order"within the crystal. Proteins are generally only a few nanometres in size.
Several thousand billion protein molecules must perfectly fit together in order to create a well-ordered crystalline structure in three dimensions.
This stage is necessary if a structure is to be obtained successfully. Sometimes crystals, which may appear macroscopically perfect,
disintegrate if subjected to X-rays, thus destroying their structure. It has been suggested that mass movements of crystalline proteins might explain this paradox,
but this supposedly slow residual dynamic had never been observed directly in a crystal. The researchers at IBS used a multi-technique approach, combining solid-state NMR spectroscopy, simulations of molecular dynamics and X-ray crystallography.
Thanks to solid-state NMR, they were able to measure the dynamics of a model protein, ubiquitin, in three of its crystalline forms.
Their results indicate that, even when crystallised, proteins continue to produce slight residual movements. The less compact the crystal
the more unrestrained the movements within it. Accordingly, crystallographic data collected for three types of crystal indicate that the more compact the crystal,
the better it defracts, making it easier to determine the structure of the proteins of which it consists.
To reconstitute the movement of proteins in these crystalline networks, simulations of molecular dynamics were performed for each of the three crystalline forms.
These simulations suggest that, within crystals, proteins revolve around each other a few degrees at microsecond speed. As shown through NMR measurements,
this swinging motion"is greater the less compact the crystal a
#Discovery about new battery overturns decades of false assumptions New findings at Oregon State university have overturned a scientific dogma that stood for decades,
by showing that potassium can work with graphite in a potassium-ion battery-a discovery that could pose a challenge and sustainable alternative to the widely-used lithium-ion battery.
Lithium-ion batteries are ubiquitous in devices all over the world, ranging from cell phones to laptop computers and electric cars.
But there may soon be a new type of battery based on materials that are far more abundant and less costly.
A potassium-ion battery has been shown to be possible. And the last time this possibility was explored was
when Herbert hoover was president, the Great depression was in full swing and the Charles Lindbergh baby kidnapping was the big news story of the year-1932."
"For decades, people have assumed that potassium couldn't work with graphite or other bulk carbon anodes in a battery,"said Xiulei (David) Ji,
the lead author of the study and an assistant professor of chemistry in the College of Science at Oregon State university."
"That assumption is said incorrect, "Ji.""It's really shocking that no one ever reported on this issue for 83 years."
"The Journal of the American Chemical Society published the findings from this discovery("Carbon Electrodes for K-Ion Batteries),
"which was supported by the U s. Department of energy and done in collaboration with OSU researchers Zelang Jian and Wei Luo.
because they open some new alternatives to batteries that can work with well-established and inexpensive graphite as the anode,
or high-energy reservoir of electrons. Lithium can do that, as the charge carrier whose ions migrate into the graphite
and create an electrical current. Aside from its ability to work well with a carbon anode
however, lithium is quite rare, found in only 0. 0017 percent, by weight, of the Earth's crust.
The new findings show that it can work effectively with graphite or soft carbon in the anode of an electrochemical battery.
Right now, batteries based on this approach don't have performance that equals those of lithium-ion batteries,
"It's safe to say that the energy density of a potassium-ion battery may never exceed that of lithium-ion batteries,
and be ready to take the advantage of the existing manufacturing processes of carbon anode materials."
"Electrical energy storage in batteries is essential not only for consumer products such as cell phones and computers,
but also in transportation industry power backup, micro grid storage, and for the wider use of renewable energy y
#Detecting HIV diagnostic antibodies with DNA nanomachines Detecting HIV diagnostic antibodies with DNA nanomachines (Nanowerk News) New research may revolutionize the slow,
cumbersome and expensive process of detecting the antibodies that can help with the diagnosis of infectious and autoimmune diseases such as rheumatoid arthritis and HIV.
An international team of researchers have designed and synthetized a nanometer scale DNA"machine "whose customized modifications enable it to recognize a specific target antibody.
Their new approach, which they described this month in Angewandte Chemie("A Modular, DNA-Based Beacon for Single-Step Fluorescence Detection of Antibodies and Other Proteins"),
"promises to support the development of rapid, low-cost antibody detection at the point-of-care, eliminating the treatment initiation delays
and increasing healthcare costs associated with current techniques. New research may revolutionize the slow, cumbersome and expensive process of detecting the antibodies that can help with the diagnosis of infectious and autoimmune diseases such as rheumatoid arthritis and HIV.
An international team of researchers have designed and synthesized a nanometer scale DNA"machine "whose customized modifications enable it to recognize a specific target antibody.
Their new approach, which they described this month in Angewandte Chemie, promises to support the development of rapid,
low-cost antibody detection at the point-of-care, eliminating the treatment initiation delays and increasing healthcare costs associated with current techniques.
The light-generating DNA antibody detecting nanomachine is illustrated here in action, bound to an antibody.
Image: Marco Tripodi) The binding of the antibody to the DNA machine causes a structural change (or switch),
which generates a light signal. The sensor does need not to be activated chemically and is rapid-acting within five minutes-enabling the targeted antibodies to be detected easily, even in complex clinical samples such as blood serum."
"One of the advantages of our approach is that it is said highly versatile Prof. Francesco Ricci, of the University of Rome, Tor Vergata, senior co-author of the study."
"This DNA nanomachine can be modified in fact custom so that it can detect a huge range of antibodies,
this makes our platform adaptable for many different diseases"."""Our modular platform provides significant advantages over existing methods for the detection of antibodies,"added Prof.
Valle-Blisle of the University of Montreal, the other senior co-author of the paper.""It is rapid,
does not require reagent chemicals, and may prove to be useful in a range of different applications such as point-of-care diagnostics and bioimaging"."
""Another nice feature of our this platform is said its low-cost Prof. Kevin Plaxco of the University of California, Santa barbara."
"The materials needed for one assay cost about 15 cents, making our approach very competitive in comparison with other quantitative approaches.""
""We are excited by these preliminary results, but we are looking forward to improve our sensing platform even more"said Simona Ranallo, a Phd student in the group of Prof.
Ricci at the University of Rome and first-author of the paper.""For example, we could adapt our platform
so that the signal of the nanoswitch may be read using a mobile phone. This will make our approach really available to anyone!
We are working on this idea and we would like to start involving diagnostic companies
#Robots navigating the unknown A robot with a navigation system that mirrors the neural scheme used by humans
and animals to find their way around has been developed by A*STAR researchers. This robot uses neural schemes similar to humans to navigate an office environment.
The human navigation function is operated by two types of brain cells-place cells and grid cells.
Place cells become active in the brain when we recognize familiar places, while grid cells provide us with an absolute reference system,
so we can determine exactly where we are on a map. The way sailors used to navigate through tracking of relative movement
The human brain uses grid cells, which provide a virtual reference frame for spatial awareness to handle this type of relative navigation.
and pass one of the virtual grid points that the brain has set up, the respective grid cell becomes active,
and we know our relative movement in relation to those coordinates. By using both place and grid cells for navigation,
humans and animals are able to accurately move through the environment. Yuan and the team have implemented the same neural scheme for robots,
using computer programs that simulate the activity of place and grid cells in the brain. Crucial to the computational algorithm is the strength of the feedback mechanism between the grid cells and place cells,
and the calibration of the visual signals is integral to the map building process of the computer algorithm.
The algorithm was tested in a robot (see image) that explored a 35 meter x 35 meter indoor office environment.
The robot was able to detect loops in the path through the office space and,
by using visual cues to recognize areas visited repeatedly, built its own neurological map of the office.
The computer navigation system assists the robot in situations where it is lost in a new environment,
says Yuan. Cognitive maps can help the robot when it is lost, because they can provide global topological information of the navigating environment to help the robot localize itself f
#Newly discovered'design rule'brings nature-inspired nanostructures one step closer (w/video) Scientists aspire to build nanostructures that mimic the complexity and function of nature proteins,
but are made of durable and synthetic materials. These microscopic widgets could be customized into incredibly sensitive chemical detectors or long-lasting catalysts,
to name a few possible applications. But as with any craft that requires extreme precision, researchers must first learn how to finesse the materials theyl use to build these structures.
and reported Oct 7 in the advance online publication of the journal Nature("Peptoid nanosheets exhibit a new secondary-structure motif"),
This atomic-resolution simulation of a two-dimensional peptoid nanosheet reveals a snake-like structure never seen before.
The nanosheet layers include a water-repelling core (yellow), peptoid backbones (white), and charged sidechains (magenta and cyan).
The right corner of the top layer of the nanosheet has been emovedto show how the backbone alternating rotational states give the backbones a snake-like appearance (red and blue ribbons.
Surrounding water molecules are red and white. The scientists discovered a design rule that enables a recently created material to exist.
The material is a peptoid nanosheet. It a flat structure only two molecules thick, and it composed of peptoids,
which are synthetic polymers closely related to protein-forming peptides. The design rule controls the way in
which polymers adjoin to form the backbones that run the length of nanosheets. Surprisingly, these molecules link together in a counter-rotating pattern not seen in nature.
a trait that makes peptoid nanosheets larger and flatter than any biological structure. The Berkeley Lab scientists say this never-before-seen design rule could be used to piece together complex nanosheet structures and other peptoid assemblies such as nanotubes and crystalline solids.
What more, they discovered it by combining computer simulations with x-ray scattering and imaging methods to determine, for the first time,
the atomic-resolution structure of peptoid nanosheets. his research suggests new ways to design biomimetic structures,
says Steve Whitelam, a co-corresponding author of the Nature paper. e can begin thinking about using design principles other than those nature offers.
Whitelam is a staff scientist in the Theory Facility at the Molecular Foundry, a DOE Office of Science user facility located at Berkeley Lab. He led the research with co-corresponding author Ranjan Mannige,
a postdoctoral researcher at the Molecular Foundry; and Ron Zuckermann, who directs the Molecular Foundry Biological Nanostructures Facility.
They used the high-performance computing resources of the National Energy Research Scientific Computing Center (NERSC),
another DOE Office of Science user facility located at Berkeley Lab. Peptoid nanosheets were discovered by Zuckermann group five years ago.
They found that under the right conditions, peptoids self assemble into two-dimensional assemblies that can grow hundreds of microns across.
This olecular paperhas become a hot prospect as a protein-mimicking platform for molecular design.
To learn more about this potential building material, the scientists set out to learn its atom-resolution structure.
Microscopy and scattering data gathered at the Molecular Foundry and the Advanced Light source also a DOE Office of Science user facility located at Berkeley Lab,
were compared with molecular dynamics simulations conducted at NERSC. The research revealed several new things about peptoid nanosheets.
Their molecular makeup varies throughout their structure, they can be formed only from peptoids of a certain minimum length,
they were surprised to see a design rule not found in the field of protein structural biology.
These fundamental building blocks are composed themselves of backbones, and the polymers that make up these backbones are joined all together using the same rule.
Each adjacent polymer rotates incrementally in the same direction, so that a twist runs along the backbone.
This rule doesn apply to peptoid nanosheets. Along their backbones, adjacent monomer units rotate in opposite directions.
These counter-rotations cancel each other out, resulting in a linear and untwisted backbone. This enables backbones to be tiled in two dimensions
and extended into large sheets that are flatter than anything nature can produce. t was a big surprise to find the design rule that makes peptoid nanosheets possible has eluded the field of biology until now,
says Mannige. his rule could perhaps be used to build many more unrealized structures. Adds Zuckermann, e also expect there are other design principles waiting to be discovered,
which could lead to even more biomimetic nanostructures. n
#Analyzing protein structures in their native environment Proteins can fold in different ways depending on their environment.
These different configurations change the function of the protein; misfolding is associated frequently with diseases such as Alzheimer and Parkinson.
Until now, it has been difficult to fully characterize the different structures that proteins can take on in their natural environments.
However, using a new technique known as sensitivity-enhanced nuclear magnetic resonance (NMR), MIT researchers have shown that they can analyze the structure that a yeast protein forms as it interacts with other proteins in a cell.
isolated from their usual environment. ynamic nuclear polarization has a capacity to transform our understanding of biological structures in their native contexts,
says Susan Lindquist, a professor of biology at MIT, member of the Whitehead Institute, and one of the senior authors of the paper, which appears in the Oct 8 issue of Cell("Sensitivity-Enhanced NMR Reveals Alterations in Protein Structure by Cellular Milieus").
"Robert Griffin, an MIT professor of chemistry and director of the Francis Bitter Magnet Laboratory, is also a senior author of the paper.
Kendra Frederick, a former Whitehead postdoc who is now an assistant professor at the University of Texas Southwestern,
By using a strong magnetic field that interacts with the nuclear spins of carbon atoms in the proteins,
using microwaves generated by a gyrotron, a high-frequency microwave oscillator developed in collaboration with Richard Temkin of MIT Department of physics and Plasma Science and Fusion Center.
In addition, Tim Swager and his group in the MIT Department of chemistry have developed paramagnetic polarizing agents for the experiments.
when youe thinking about its biology. To make sure they are getting data only on the protein of interest,
the researchers label their target protein with carbon-13 a stable isotope of carbon while the rest of the proteins are unlabeled. his technique has the potential to really open up a wide range of studies,
director of the NMR program at the National High Magnetic field Laboratory and a professor at Florida State university. ou don have to crystallize the proteins,
you don have to put them into a uniform solution. You can study them in their natural environment,
and that tremendously exciting, says Cross, who was not part of the research team. Protein folding In the Cell paper,
but when human proteins form amyloids they are associated usually with diseases especially neurodegenerative diseases such as Alzheimer, Parkinson,
#A stretchable far-field communication antenna far wearable electronics The age of wearable electronics is upon us as witnessed by the fast growing array of smart watches, fitness bands and other advanced,
next-generation health monitoring devices such as electronic stick-on tattoos (see for instance"wearing single-walled carbon nanotube electronics on your skin",a"temporary tattoo to monitor glucose levels"or"graphene nanosensor tattoo
on teeth monitors bacteria in your mouth")."In order for these wearable sensor devices to become fully integrated into sophisticated monitoring systems,
they require wireless interfaces to external communication devices such as smartphones. This requires far-field communication systems that,
like the sensor systems, perform even under extreme deformations and during extended periods of normal daily activities."
"While the transistors used in radio frequency (RF) circuits can be made flexible and stretchable using several techniques already demonstrated, the main component of the communication circuit,
the antenna for far-field communication, is still a challenge,"Muhammad Mustafa Hussain, an Associate professor of Electrical engineering at KAUST, tells Nanowerk.
To complement existing designs for stretchable antenna systems which usually radiate at different resonant frequencies
and are expensive due to the complex processing involved or the exotic materials used an international team led by Hussain now demonstrates a stretchable and wearable antenna that can provide a single frequency operation
while flexing or stretching. The group of researchers which included KAUST Assistant Prof. Atif Shamim and Swanlund Chair Professor John Rogers of University of Illinois at Urbana Champaign, reports their findings in the October 6, 2015 online edition of Advanced Functional Materials
("Metal/Polymer Based Stretchable Antenna for Constant Frequency Far-Field Communication in Wearable Electronics"."The paper will be the front cover article of the print edition.
The team's flexible and stretchable metal thin-film (copper) antenna for far-field communication up to 80 meters
while mounted on a stretchable fabric and worn by a person maintains its properties during stretching,
bending and strain cycles.""We fabricated our antenna using a metal/polymer bilayer process the resulting structure combines the conductivity of the metal
and the elasticity of the polymer and the stretchability is imparted using a lateral spring structure,
"explains Aftab Hussain, a Phd candidate in Hussain's lab and the paper's first author."
"The key reason the antenna needed to be fabricated as a metal/polymer bilayer is that standalone metal thin films are very malleable,
and deform plastically under application of stress.""That means that a metal thin film lateral spring structure cannot be used as a stretchable antenna,
since it will only be able to undergo one stretch cycle. The solution to this problem was to use a polymer backing that provides the restoration force
which helps the spring return to its original shape after the release of the applied lateral force.
As a result, the key performance parameters of the antenna do not change with bending,
stretching, flexing and twisting hence the antenna can continuously communicate information in the Wifi frequency band
while it is worn. In their tests the researchers found that their antenna retains all its essential properties such as gain, radiation pattern, directionality, operation frequency and bandwidth for up to 30%strain and for 2000 stretching cycles.
As a next step, the team will integrate their stretchable antenna into a fully integrated, flexible, stretchable and wearable sensor array for real-time communication of sensor information s
#Soft probing with optical tweezers Surfaces separate outside from inside, control chemical reactions, and regulate the exchange of light, heat, and moisture.
In the journal Nature Nanotechnology("Surface imaging beyond the diffraction limit with optically trapped spheres"),the Freiburg physicist Prof.
and has the purpose of generating height profiles of soft surfaces like biofilms or cell membranes.
which is established well in nanotechnology. An AFM uses a small spring arm-a needle with an ultra-thin tip-to scan a surface.
In a PFM, the spring arm is replaced by a small plastic sphere that sits at the center of a so-called optical trap and runs along the surface.
The sphere is less than 200 nanometers in diameter making it 500 times thinner than a human hair.
Alexander Rohrbach conducts research at the Department of Microsystems Engineering (IMTEK) and is an associate member of the Cluster of Excellence BIOSS Centre for Biological Signalling Studies of the University of Freiburg g
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