#Milestone single-biomolecule imaging technique may advance drug design Knowing the detailed shape of biomolecules such as proteins is essential for biological studies and drug discovery.
Modern structural biology relies on techniques such as nuclear magnetic resonance (NMR), X-ray crystallography and cryo-electron microscopy to discover the tiny structural details of biomolecules.
All these methods, however, require averaging over a large number of molecules and thus structural details of an individual biomolecule are lost often.
Now researchers from the University of Zurich, Switzerland have made a breakthrough by obtaining the first nanometer (one billionth of a meter) resolved image of individual tobacco mosaic virions
a rod-shaped RNA VIRUS that infects a wide range of plants, especially tobacco. The work demonstrates the potential of low energy electron holography as a non-destructive,
single-particle imaging technique for structural biology. The researchers describe their work in a paper published this week on the cover of the journal Applied Physics Letters, from AIP Publishing."
"We've shown that by means of low energy holography, it is possible to image individual tobacco mosaic virions deposited on ultraclean freestanding graphene,
"said Jean-Nicolas Longchamp, the primary author and a postdoctoral fellow of the Physics department at the University of Zurich, Switzerland."
"The virions are imaged with one nanometer resolution exhibiting details of the helical structure of the virus. Our technique would be the first non-destructive imaging tool for structural biology at the truly single molecule level."
"Longchamp noted the technique would also open the door for"rational drug design,"an inventive process of finding new medications based on the knowledge of a biological target.
In the most basic sense, drug design searches for and chemically refines molecules that have some complementarity in shape
and charge to some part of another molecule--such as the binding site of a human protein involved in some physiological process that goes awry in a given disease.
Second, low energy electrons are harmless to biomolecules, "Longchamp said. In many conventional techniques such as transmission electron microscopy, the possible resolution is limited by high-energy electrons'radiation damage to biological samples.
Individual biomolecules are destroyed long before an image of high enough quality can be acquired. In other words, the low permissible electron dose in conventional microscopies is not sufficient to obtain high-resolution images from a single biomolecule.
However in low energy electron holography, the employed electron doses can be much higher--even after exposing fragile molecules like DNA or proteins to a electron dose more than five orders of magnitude higher
than the critical dose in transmission electron microscopy, no radiation damage could be observed. Sufficient electron dose in low energy electron holography makes imaging individual biomolecules at a nanometer resolution possible.
In Longchamp's experiment, the tobacco mosaic virions were deposited on a freestanding, ultraclean graphene, an atomically thin layer of carbon atoms arranged in a honeycomb lattice.
The graphene substrate is similar to a glass slide in optical microscopy which is conductive, robust and transparent for low energy electrons.
Using a distant detector on the other side of the sample, the researchers recorded the sample's high-resolution hologram,
the current nanometer resolution could be improved to angstrom (one ten billionth of a meter) or atomic resolution in the near future by improving the mechanical stability of the microscope."
"While by now single proteins have been imaged with nanometer resolution using the same technique, the researchers'next step is to image a single protein at atomic resolution--something that has never been done before e
#Carbon nanotubes Applied to Create Electrical conductivity in Woolen Fabrics The fabrics can be used in various industries,
including medicine, building, textile and military after being mass-produced. Among textile products, woolen fabrics are used in various industries due to their unique properties such as insulation and flexibility.
The production of fabrics with new properties such as electrical conductivity is among the changes. Researchers have tried in this research to synthesize fabrics with new properties by using simple and modified carbon nanotubes.
Based on the results the application of nanotubes and modification of the sample surfaces lead to the production of conductive fabrics with different electrical properties.
The synthesis of these fabrics will open new windows to the production of composites with conventional and innovative applications.
Carbon nanotubes have been added to woolen fabrics that are insulators by themselves. Therefore, the product can be presented to the market as a relatively conductive material.
The fabrics can be used in the production of normal and industrial clothes, and also in protective clothes in military industry y
#Wearable electronic health patches may now be cheaper and easier to make A team of researchers in the Cockrell School of engineering at The University of Texas at Austin has invented a method for producing inexpensive and high-performing wearable patches
potentially outperforming traditional monitoring tools such as cardiac event monitors. The researchers published a paper on their patent-pending process in Advanced Materials on Sept. 23.
Led by Assistant professor Nanshu Lu, the team's manufacturing method aims to construct disposable tattoo-like health monitoring patches for the mass production of epidermal electronics,
a popular technology that Lu helped develop in 2011. The team's breakthrough is a repeatable"cut
The researchers believe their new method is compatible with roll-to-roll manufacturing--an existing method for creating devices in bulk using a roll of flexible plastic and a processing machine.
Reliable, ultrathin wearable electronic devices that stick to the skin like a temporary tattoo are a relatively new innovation.
"One of the most attractive aspects of epidermal electronics is their ability to be said disposable,
and portable process for producing these electronics, which, unlike the current method, does not require a clean room, wafers and other expensive resources and equipment.
which is similar in scope to 3-D printing but different in that material is removed instead of added.
industrial-quality metal deposited on polymer sheets. First, an electronic mechanical cutter is used to form patterns on the metal-polymer sheets.
Second, after removing excessive areas, the electronics are printed onto any polymer adhesives, including temporary tattoo films.
The cutter is programmable so the size of the patch and pattern can be customized easily.
Deji Akinwande, an associate professor and materials expert in the Cockrell School, believes Lu's method can be transferred to roll-to-roll manufacturing."
In each test, the researchers'newly fabricated patches picked up body signals that were stronger than those taken by existing medical devices,
including an ECG/EKG, a tool used to assess the electrical and muscular function of the heart.
"We are trying to add more types of sensors including blood pressure and oxygen saturation monitors to the low-cost patch."
The University of Texas at Austin is committed to transparency and disclosure of all potential conflicts of interest.
The university investigator who led this research, Nanshu Lu, has submitted required financial disclosure forms with the university.
Lu is cofounder and scientific adviser for Stretch Med Inc.,a medical device company in which she has an equity partnership.
Stretch Med is developing human electrophysiological sensors for clinical use, drawing on some of the patent-pending technologies described in this release e
#Extending a battery's lifetime with heat: Researchers from California Institute of technology find that heat can break down the damaging branch-like structures that grow inside batteries,
which may possibly be used to extend battery lifetimes A battery cell consists of a positive and negative electrode,
called the cathode and anode. As the battery produces electrical current, electrons flow from the anode through a circuit outside the battery and back into the cathode.
Having lost the electrons that are generating the current, some of the atoms in the anode--an electrically conductive metal like lithium--become ions that then travel to the cathode,
moving through a conductive liquid medium called an electrolyte. Recharging the battery reverses the process,
and the ions travel back and stick onto the anode. But when they do, the ions don't attach evenly.
Instead, they form microscopic bumps that eventually grow into long branches after multiple recharging cycles. When these dendrites reach
and contact the cathode, they form a short circuit. Electrical current now flows across the dendrites instead of the external circuit,
rendering the battery useless and dead. The current also heats up the dendrites, and because the electrolyte tends to be flammable,
the dendrites can ignite. Even if the dendrites don't short circuit the battery, they can break off from the anode entirely
and float around in the electrolyte. In this way, the anode loses material, and the battery can't store as much energy."
"Dendrites are hazardous and reduce the capacity of rechargeable batteries, "said Asghar Aryanfar, a scientist at Caltech, who led the new study that's published this week on the cover of The Journal of Chemical Physics, from AIP Publishing.
Although the researchers looked at lithium batteries, which are among the most efficient kind, their results can be applied broadly."
"The dendrite problem is general to all rechargeable batteries, "he said. The researchers grew lithium dendrites on a test battery
and heated them over a couple days. They found that temperatures up to 55 degrees Celsius shortened the dendrites by as much as 36 percent.
To figure out what exactly caused this shrinkage, the researchers used a computer to simulate the effect of heat on the individual lithium atoms that comprise a dendrite,
which was modeled with the simple, idealized geometry of a pyramid. The simulations showed that increased temperatures triggered the atoms to move around in two ways.
The atom at the tip of the pyramid can drop to lower levels. Or an atom at a lower level can move
and leave behind a vacant spot, which is filled then by another atom. The atoms shuffle around,
generating enough motion to topple the dendrite. By quantifying how much energy is needed to change the structure of the dendrite,
Aryanfar said, researchers can better understand its structural characteristics. And while many factors affect a battery's longevity at high temperatures--such as its tendency to discharge on its own
or the occurrence of other chemical reactions on the side--this new work shows that to revitalize a battery,
all you might need is some extra heat. The authors of this study are affiliated with the California Institute of technology y
#Brightness-equalized quantum dots improve biological imaging"In this work, we have made two major advances--the ability to precisely control the brightness of light-emitting particles called quantum dots,
and the ability to make multiple colors equal in brightness, "explained Andrew M. Smith, an assistant professor of bioengineering at Illinois."Previously light emission had an unknown correspondence with molecule number.
Now it can be tuned precisely and calibrated to accurately count specific molecules. This will be particularly useful for understanding complex processes in neurons
and cancer cells to help us unravel disease mechanisms, and for characterizing cells from diseased tissue of patients.""
""Fluorescent dyes have been used to label molecules in cells and tissues for nearly a century, and have molded our understanding of cellular structures and protein function.
But it has always been challenging to extract quantitative information because the amount of light emitted from a single dye is unstable and often unpredictable.
Also the brightness varies drastically between different colors, which complicates the use of multiple dye colors at the same time.
These attributes obscure correlations between measured light intensity and concentrations of molecules,"stated Sung Jun Lim, a postdoctoral fellow and first author of the paper"
Brightness-Equalized Quantum dots,"published this week in Nature Communications. According to the researchers, these new materials will be especially important for imaging in complex tissues
and living organisms where there is a major need for quantitative imaging tools, and can provide a consistent
and tunable number of photons per tagged biomolecule. They are expected also to be used for precise color matching in light-emitting devices and displays,
and for photon-on-demand encryption applications. The same principles should be applicable across a wide range of semiconducting materials."
allow quantitative multicolor imaging in biological tissue, and improve color tuning in light-emitting devices.
These attributes should lead to new LEDS and display devices not only with precisely matched colors--better color accuracy and brightness--but also with improved performance lifetime and improved ease of manufacturing."
"QDS are already in use in display devices (e g. Amazon Kindle and a new Samsung TV
#Graphene teams up with two-dimensional crystals for faster data communications Ultra-fast detection of light lies at the heart of optical communication systems nowadays.
Driven by the internet of things and 5g, data communication bandwidth is growing exponentially, thus requiring even faster optical detectors that can be integrated into photonic circuits.
In the recent work published today in Nature Nanotechnology, the research group led by Prof at ICFO Frank Koppens has shown that a two-dimensional crystal,
combined with graphene, has the capability to detect optical pulses with a response faster than ten picoseconds,
while maintaining a high efficiency. By using ultra-fast laser pulses the researchers have shown a record-high photo-response speed for a heterostructure made of two-dimensional materials.
which is just a few nanometers thick can have such high performance, "ICFO researcher Mathieu Massicotte and first author of this study states that"Everyone knew graphene could make ultrafast photodetectors,
but related two-dimensional crystals were still lagging very much behind. In our work we show that by teaming up these two materials,
we can obtain a photodetector that is not only ultrafast but also highly efficient.""The results obtained from this study have shown that the stacking of semiconducting 2d materials with graphene in heterostructures could lead to new, fast and efficient optoelectronic applications,
such as high-speed integrated communication systems s
#Superconductivity trained to promote magnetization: Russian scientist and her colleagues discovered the superconductivity effect, which will help to create future supercomputers Superconductivity,
which is almost incompatible with magneticfield, under certain conditions is able to promote magnetization. Russian scientist Natalya Pugach from the Skobeltsyn Institute of Nuclear physics at the Lomonosov Moscow State university discovered this yet to be explained effect with her British colleagues,
whose theory group headed by Professor Matthias Eschrig. They suggest that techniques based on this effect are able to move us closer to future supercomputers:
spintronic devices. Their study was published in the prestigious Nature Physics journal. The research team, which included Natalya Pugach from the Skobeltsyn Institute of Nuclear physics, studied the interactions between superconductivity
and magnetization in order to understand how to control electron spins (electron magnetic moments) and to create the new generation of electronics.
In traditional microelectronics information is coded via the electric charges. In spin electronics-or spintronics-information is coded via the electron spin,
which could be directed along or against particular axis."Superconducting spintronic devices will demand far less energy
and emit less heat. It means that this technology will allow to create much more economical and stable computing machines and supercomputers,
"--Natalya Pugach explains. The main obstacle to the development of these devices lies in the fact,
that the spins of the electron and of other charged particles are very difficult to control.
The results of this new research show, that superconductors may be useful in the process of spin transportation, and ferromagnetics may be used to control spins.
Superconducting state is very responsive sensitive to magnetic fields: strong magnetic fields destroy it, but and superconductors expel the magnetic field completely.
It is almost impossible to make ordinary superconductors and magnetic materials interact with each other due to their opposite magnetic ordering direction of magnetization:
in magnetic layers storages the magnetic field tends to arrange spins in one direction, and the Cooper pair (BCS pair) in ordinary superconductors haves opposite spins."
"My colleagues experimented with devices called superconducting spin-valves. They look like a"sandwich, "made of nanolayers of ferromagnetic material, superconductor and other metals.
By changing the direction of magnetization it is possible to control the current in superconductor.
The thickness of layers is crucial, because in case of the"thick"superconductor it is impossible to see any interesting effects,
"--Natalya Pugach explains. During the experiments scientists bombarded the experimental samples with muons (particles that resemble electrons,
but are 200 times heavier) and analyzed their dissipation scattering. This method gave the researchers the possibility to understand
how the magnetization proceeds in different layers of the sample. The spin-valve consisted of two ferromagnetic cobalt layers, one superconductive niobium layer with thickness of approximately 150 atoms and a layer of gold.
In the experiment researchers discovered an unexpected effect: when magnetization directions in two ferromagnetic layers were not parallel,
the interaction between these layers and superconductive layer produced induced magnetization in the gold layer,"overjumping"the superconductor.
When scientists changed the magnetization directions in two layers, making them parallel, this effect almost disappeared:
field intensity experienced twentyfold decrease.""This effect was unexpected. We were surprised very to discover it. Previously we tried to explain the results with another magnetization distribution pattern,
that was predicted before, but in vain. We have some hypotheses, but we still do not have any complete explanation.
But nevertheless this effect allows us to use the new method of manipulations with spins,
that the finding will allow development to develop conceptually new spintronic elements. According to Natalya Pugach, superconductive spintronics technologies may help to build supercomputers and powerful servers,
whose energy consumption and heat emission create much more problems than in case of ordinary desktop computers.""Development of computer technologies was based on semiconductors.
They are good for personal computers, but when you use these semiconductors to build supercomputers, they produce heat and noise, demand powerful cooling systems.
Spintronics allows to solve all these problems, "--Natalya Pugach concludes s
#Discovery about new battery overturns decades of false assumptions Abstract: 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, which was supported by the U s. Department of energy and done in collaboration with OSU researchers Zelang Jian and Wei Luo.
A patent is also pending on the new technology. The findings are of considerable importance,
researchers say, 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.
Because of that it's comparatively expensive, and it's difficult to recycle. Researchers have yet to duplicate its performance with less costly and more readily available materials, such as sodium, magnesium, or potassium."
"The cost-related problems with lithium are sufficient that you won't really gain much with economies of scale,
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. OSU officials say they are seeking support for further research
Mcmaster engineers build better energy storage device Mcmaster Engineering researchers Emily Cranston and Igor Zhitomirsky are turning trees into energy storage devices capable of powering everything from a smart watch to a hybrid car.
an organic compound found in plants, bacteria, algae and trees, to build more efficient and longer-lasting energy storage devices or supercapacitors.
and high-power electronics, such as wearable devices, portable power supplies and hybrid and electric vehicles.""Ultimately the goal of this research is to find ways to power current and future technology with efficiency
of particular interest are based nanocellulose materials. The work by Cranston, an assistant chemical engineering professor, and Zhitomirsky, a materials science and engineering professor, demonstrates an improved three-dimensional energy storage device constructed by trapping functional nanoparticles within the walls of a nanocellulose foam.
The foam is made in a simplified and fast one-step process. The type of nanocellulose used is called cellulose nanocrystals
and looks like uncooked long-grain rice but with nanometer-dimensions. In these new devices, the'rice grains'have been glued together at random points forming a mesh-like structure with lots of open space
hence the extremely lightweight nature of the material. This can be used to produce more sustainable capacitor devices with higher power density
and faster charging abilities compared to rechargeable batteries. Lightweight and high-power density capacitors are of particular interest for the development of hybrid and electric vehicles.
The fast-charging devices allow for significant energy saving, because they can accumulate energy during braking and release it during acceleration."
"I believe that the best results can be obtained when researchers combine their expertise, "Zhitomirsky says."
"Emily is an amazing research partner. I have been impressed deeply by her enthusiasm, remarkable ability to organize team work
and generate new ideas
#Room temperature magnetic skyrmions, a new type of digital memory?""This is a potentially new way to store information,
and the energy costs are expected to be said extremely low Kai Liu, professor of physics at UC Davis and corresponding author of a paper on the work, published in the journal Nature Communications Oct 8.
Skyrmions were described originally over 50 years ago as a type of hypothetical particle in nuclear physics. Actual magnetic skyrmions were discovered only in 2009,
as chiral patterns of magnetic moments--think of a moment as a tiny compass needle--in materials close to absolute zero temperature, in the presence of a strong magnetic field.
Magnetic skyrmions fall into two types Liu said:""Bloch skyrmions,"with a hurricane-like spiral pattern of magnetic moments around a perpendicular center, surrounded by magnetic moments oriented in the opposite direction to the center;
and"hedgehogs,"where the magnetic moments orient like spikes on a hedgehog or sea urchin. The interesting thing about magnetic skyrmions, Liu said,
is that they are protected"topologically:""they can be deformed continuously, in the same way that a coffee mug shape can be deformed into a bagel shape,
That means they can potentially store information at an energy cost much lower than current technology,
Together with graduate student Dustin Gilbert, now a postdoctoral fellow at NIST, Liu and colleagues designed a nanosynthesis approach to achieve artificial"Bloch"magnetic skyrmions at room temperature.
They created a pattern of magnetic nanodots, each about half a micron across on a multilayered film where the magnetic moments are aligned normal to the plane.
they were able to find the first direct evidence of arrays of stable spiral magnetic skyrmions beneath the nanodots at room temperature,
even without an external magnetic field. The availability of stable magnetic skyrmions at room temperature opens up new studies on their properties and potential development in electronic devices,
such as nonvolatile magnetic memory storage. Coauthors on the paper are Brian Maranville, Andrew Balk, Brian Kirby, Daniel Pierce, John Unguris and Julie Borchers at NIST,
and Peter Fischer, LBL and UC Santa cruz. Nanofabrication work and other characterizations were carried out in Liu's laboratory
and at the Center for Nano and Micro Manufacturing at UC Davis. The work was funded by the National Science Foundation n
#Scientists pave way for diamonds to trace early cancers Physicists from the University of Sydney have devised a way to use diamonds to identify cancerous tumours before they become life threatening.
reveal how a nanoscale, synthetic version of the precious gem can light up early-stage cancers in nontoxic, noninvasive Magnetic resonance imaging (MRI) scans.
Targeting cancers with tailored chemicals is not new but scientists struggle to detect where these chemicals go since,
short of a biopsy, there are few ways to see if a treatment has been taken up by a cancer.
Led by Professor David Reilly from the School of Physics researchers from the University investigated how nanoscale diamonds could help identify cancers in their earliest stages."
"We knew nano diamonds were of interest for delivering drugs during chemotherapy because they are largely nontoxic and non-reactive,
"says Professor Reilly.""We thought we could build on these nontoxic properties realising that diamonds have magnetic characteristics enabling them to act as beacons in MRIS.
We effectively turned a pharmaceutical problem into a physics problem.""Professor Reilly's team turned its attention to hyperpolarising nanodiamonds,
a process of aligning atoms inside a diamond so they create a signal detectable by an MRI SCANNER."
"By attaching hyperpolarised diamonds to molecules targeting cancers the technique can allow tracking of the molecules'movement in the body,
"says Ewa Rej, the paper's lead author.""This is a great example of how quantum physics research tackles real-world problems,
in this case opening the way for us to image and target cancers long before they become life-threatening,
"says Professor Reilly. The next stage of the team's work involves working with medical researchers to test the new technology on animals.
Also on the horizon is research using scorpion venom to target brain tumours with MRI scanning g
Overtext Web Module V3.0 Alpha
Copyright Semantic-Knowledge, 1994-2011