where molecules are designed to spontaneously assemble into desired structures. Self-assembly requires a burst of heat to make the molecules snap into the proper configurations.
Here an intensely hot laser swept across the sample to transform disordered polymer blocks into precise arrangements in just seconds."
These molecules then glom onto the self-assembled polymer, converting it into a metallic mesh.
The electromagnetic field is likely affecting the interaction between the nanomaterial and the drug molecules, Borgens said."
and retains the remaining drug molecules.""For each different drug the team would need to find the corresponding optimal electromagnetic field for its release,
"This collaborative team was one of two to first demonstrate polaritons in single-atom layers of carbon called graphene.
In graphene, infrared light launches ripples through the electrons at the surface of this metallike material called surface plasmon polaritons that the researchers were able to control using a simple electrical circuit.
Columbia engineers and colleagues create bright, visible light emission from one-atom thick carbon June 15th, 2015research partnerships Lancaster University revolutionary quantum technology research receives funding boost June 22nd, 2015fabricating inexpensive, high-temp SQUIDS for future electronic devices June 22nd,
Using an engineered strain of Stenotrophomonas maltophilia to control particle size the team biosynthesized QDS using bacteria
Techconnect is the world's largest accelerator for industry-vetted emerging-technologies ready for commercialization June 11th, 2015investigation of Optical Properties of Quantum dots in Presence of Magnetic, Electrical Fields June 10th,
The interaction between liquid crystal molecules and plasmon waves on the nanostructured metallic surface played the key role in generating the polarization-independent
"At just one atom thick, graphene is the thinnest substance capable of conducting electricity. It is very flexible
"In 2012 the teams of Prof Craciun and Profesor Russo, from the University of Exeter's Centre for Graphene science, discovered that sandwiched molecules of ferric chloride between two graphene layers make a whole new system that is the best known
#X-rays and electrons join forces to map catalytic reactions in real-time: New technique combines electron microscopy and synchrotron X-rays to track chemical reactions under real operating conditions A team of scientists used a newly developed reaction chamber to combine x-ray absorption spectroscopy and electron microscopy for an unprecedented portrait of a common chemical reaction.
including single atoms and larger structures, during an active reaction at room temperature,"said study coauthor and Brookhaven Lab scientist Eric Stach."
a focused electron beam passes through the sample and captures images of the nanoparticles within.
"With TEM, we take high-resolution pictures of the particles to directly see their size and distribution,"said Stach,
Particles smaller than a single nanometer were hidden behind what we call the resolution curtain of the technique."
which are measured to identify its chemical composition--in this instance, the distribution of platinum particles.""The XAS and TEM data, analyzed together,
and only the combination of techniques could reveal all catalytic particles.""Versatile micro-reactor The new micro-reactor was designed specifically
"A relatively straightforward mathematical approach allowed them to deduce the total number of ultra-small particles missing in the TEM data."
which incorporates particles of all sizes, and removed the TEM results covering particles larger than one nanometer--the remainder fills in that crucial subnanometer gap in our knowledge of catalyst size
and distribution during each step of the reaction, "Frenkel said. Added Stach,"In the past, scientists would look at data before and after the reaction under model conditions, especially with TEM,
and complementary x-ray and electron probe techniques over time. NSLS ended its 32-year experimental run in the fall of 2014,
"Through Laboratory Directed Research and development funding, we will be part of the initial experiments at the Submicron Resolution X-ray (SRX) Spectroscopy beamline this summer,
And that's just one of the NSLS-II beamlines where we plan to deploy this technique."
PEMFC as an optimal solution for the future energy economypolymer electrolyte membrane or proton exchange membrane fuel cell (PEMFC), where chemical energy is converted directly to electrical energy,
It is known that splitting a hydrogen molecule at the anode of fuel cell using platinum is relatively easy.
splitting the oxygen molecule at the cathode of fuel cell (oxygen reduction reaction(,ORR)) is more difficult
and nearly all current PEMFC uses platinum particles on porous carbon supports to catalyze both hydrogen oxidation and oxygen reduction.
while ions can still migrate from the anode to the cathode. The electrolyte plays a key role.
It must permit only the appropriate ions to pass between the anode and cathode. If free electrons or other substances could travel through the electrolyte,
they would short circuit the current in the fuel cell and fuel cell degradation occurs. Advancements in the electrolyte system of PEMFCTHE commercial development of a special electrolyte (single ion conducting polymer electrolyte) changed the field of electrochemical devices in a significant way.
Electrochemists have spent many years in a continuing search for newer, more highly conducting (ions and not electrons) and a more electrochemically stable electrolyte system.
With the development of a single ion (for example only hydrogen ions in PEMFC) conducting polymer, electrochemists have the ability to choose from a variety of polymers with both high conductivity for a given ion of interest (off course hydrogen ions
in PEMFC) as well as excellent stability and process-ability allowing the design of electrochemical devices (such as PEMFC) in their most ideal format (3). The broad class of electrolyte (electrolyte is a polymer
removing dust particles and contamination. This self-cleansing action is due to the presence of a special surface layer
2015x-rays and electrons join forces to map catalytic reactions in real-time: New technique combines electron microscopy and synchrotron X-rays to track chemical reactions under real operating conditions June 29th,
2015chemistry X-rays and electrons join forces to map catalytic reactions in real-time: New technique combines electron microscopy and synchrotron X-rays to track chemical reactions under real operating conditions June 29th,
2015x-rays and electrons join forces to map catalytic reactions in real-time: New technique combines electron microscopy and synchrotron X-rays to track chemical reactions under real operating conditions June 29th, 2015announcements June 29th, 2015efforts to Use Smart Nanocarriers to Cure Leukemia Yield Promising
2015x-rays and electrons join forces to map catalytic reactions in real-time: New technique combines electron microscopy and synchrotron X-rays to track chemical reactions under real operating conditions June 29th, 2015energy June 29th, 2015making new materials with micro-explosions:
2015x-rays and electrons join forces to map catalytic reactions in real-time: New technique combines electron microscopy and synchrotron X-rays to track chemical reactions under real operating conditions June 29th,
2015fuel Cells X-rays and electrons join forces to map catalytic reactions in real-time: New technique combines electron microscopy and synchrotron X-rays to track chemical reactions under real operating conditions June 29th, 2015buckle up for fast ionic conduction June 16th, 2015a protective shield for sensitive catalysts:
Hydrogels block harmful oxygen June 15th, 2015nist's'nano-raspberries'could bear fruit in fuel cells June 9th, 201 2
which some of the metallic ions are placed. The size and shape of the pores are very effective in the selective sorption of the ions.
Based on the positive results the nanosorbent can be used in various industries such as foodstuff and petroleum to detect
News and information Samsung's New Graphene technology Will Double Life Of Your Lithium-Ion Battery July 1st,
2015announcements Samsung's New Graphene technology Will Double Life Of Your Lithium-Ion Battery July 1st, 2015researchers from the UCA, key players in a pioneering study that may explain the origin of several digestive diseases June 30th,
2015interviews/Book reviews/Essays/Reports/Podcasts/Journals/White papers Samsung's New Graphene technology Will Double Life Of Your Lithium-Ion Battery July 1st,
so stable that it can accurately measure the 3d movement of individual molecules over many hours--hundreds of times longer than the current limit measured in seconds.*
including moving molecules around the interior of a cell or copying DNA into another form of genetic material, RNA.
The method uses two lasers to measure the positions of opposite ends of a molecule,
They discovered through neutron scattering experiments at BER II not only how the crystal structure changes, but also uncovered new magnetic phases.
highly symmetrical planes of oxygen atoms (somewhat like a densely packed box of marbles) where different metallic elements are lodged in the spaces between them.
The embedded metal ions in the Ni1-xcuxcr2o4 spinel system cause a distortion of the crystal structure.
or copper atoms sit at what are referred to as tetragonal sites of the crystal structure. Due to their different configurations of electrons, these tetrahedra become elongated along the crystallographic c-axis for nickel,
while for copper they are compressed (Jahn-Teller effect). The distortion of the crystal structure can thus be controlled,
Phase diagramm between 2 and 900 Kelvin Using neutron scattering experiments at the BER II research reactor,
since the kinetic energy of the atoms still suppresses the Jahn-Teller effect and magnetic ordering cannot become established.
"Atoms are not just spheres. They do crazy things, especially when they are in a geometrical system like a crystal,
Using the X-ray microscope at the Advanced Light source and the X-ray Photoemission Electron microscopy (XPEEM) beamline at BESSY II,
who is responsible for the XPEEM beamline at HZB. 3d reconstruction of magnetic patternsin the end,
However, so far only electron holography could be considered for mapping magnetic domains of three-dimensional objects at the nanometre scale.
able to pick up on subtle differences in glycoprotein molecules, can improve the accuracy and efficiency of prostate cancer diagnosis. Researchers at the University of Birmingham believe that the novel technology will help improve the process of early stage diagnosis. Glycoprotein molecules,
proteins that are covalently bound to one or more carbohydrate chains, perform a wide range of functions in cell surfaces, structural tissues and blood.
targeted glycoprotein molecules that are differentiated by their modified carbohydrate chains. In doing so, they developed a more accurate and efficient way of diagnosing prostate cancer than the current tests
"Most previous research on detecting glycoproteins centered on the protein of the molecule. Problematically for diagnosis, the protein part of glycoproteins does not always change
The findings, published in the journal Chemical science, show how the rate of false readings that come with antibody based diagnosis can be reduced by the smart technology that focuses on the carbohydrate part of the molecule.
which has specific sugars in a specific location in the molecule. Professor Mendes added""Biomarkers such as glycoproteins are essential in diagnostics as they do not rely on symptoms perceived by the patient,
the sugar part of the prostate cancer glycoprotein is reacted with a custom-designed molecule that contains a boron group at one end (the boron linkage forms a reversible bond to the sugar).
The other end of this custom molecule is made to react with molecules that have been tethered to a gold surface.
before the rest of the surface is blocked with a third molecule. When the glycoprotein is removed (by breaking the reversible boron bonds) it leaves behind a perfect cast.
Within that cast, there was a special area with boron-containing molecules that can recognise a specific set of sugars.
instead depends upon the uncanny ability of gold atoms to trap silicon-carrying electrons to selectively prevent the etching.
the researchers found that even a sparse cover of gold atoms over the silicon matrix would prevent etching from occurring in their proximity.
and purify major harmful substances of cigarette smoke. the KIST-developed catalyst removes 100%of the particle substances of cigarette smoke, such as nicotine and tar,
The oxygen radical is a chemically reactive molecule, which includes oxygen atoms. It has high oxidizing power with high reactivity,
and is reported to be effective to process pollutants in the air. Oxygen radicals that fail to react with pollutants are joined together after reaction
and are converted to innocuous oxygen (O2) before being discharged into the surrounding. 2. Oxygen radical Oxygen radical is an oxygen atom in the atomic state prior to being combined into a molecule. 3. Total volatile organic compounds (TVOC
because they have consisted only of a few layers of thermal conductive atoms. When you try to add more layers of graphene,
i e. the addition of a property-altering molecule. Having tested several different additives, the Chalmers researchers concluded that an addition of (3-Aminopropyl) triethoxysilane (APTES) molecules has desired the most effect.
When heated and put through hydrolysis, it creates so-called silane bonds between the graphene and the electronic component (see picture).
#A tunable, highly sensitive graphene-based molecule sensor: Researchers at EPFL and ICFO have developed a reconfigurable sensor made from graphene to detect nanomolecules such as proteins and drugs;
molecule sensor. The results are described in an article appearing in the latest edition of the journal Science.
Focussing light to improve sensingthe researchers used graphene to improve on a well-known molecule-detection method:
In the standard method, light is used to excite the molecules, which vibrate differently depending on their nature.
By virtue of this vibration, the molecules reveal their presence and even their identity. This"signature"can be"read"in the reflected light.
however, in detecting nanometrically-sized molecules. The wavelength of the infrared photon directed at a molecule is around 6 microns (6, 000 nanometres),
while the target measures only a few nanometres. It is very challenging to detect the vibration of such a small molecule in reflected light.
This is where graphene comes in. If given the correct geometry graphene is capable of focussing light on a precise spot on its surface
and"hearing"the vibration of a nanometric molecule that is attached to it. In this study, researchers first pattern nanostructures on the graphene surface by bombarding it with electron beams and etching it with oxygen ions.
When the light arrives, the electrons in graphene nanostructures begin to oscillate. This phenomenon concentrates light into tiny spots,
which are comparable with the dimensions of the target molecules. It is then possible to detect nanometric compounds in proximity to the surface.
From ICFO, focussing on future industrial applications of this new sensor Prof. Valerio Pruneri commented that"the concept can be used in different application fields,
Reconfiguring graphene in real time to see the molecule's structurein addition to identifying the presence of nanometric molecules,
this process can also reveal the nature of the bonds connecting the atoms that make up the molecule.
Making graphene's electrons oscillate in different ways makes it possible to"read"all the vibrations of the molecule on its surface."
It gave us a full picture of the molecule, "said Hatice Altug. A big step closer to using graphene for molecule sensingthe new graphene-based process represents a major step forward for the researchers, for several reasons.
First, this simple method shows that it is possible to conduct a complex analysis using only one device,
as supported by electron energy loss spectroscopy (EELS) measurements and also by the fact that no anelastic behaviour could be observed under tension.
the bonds between atoms are stretched or compressed to accommodate the bending, but in nanoscale materials there is time for the atoms to also move,
or diffuse, from the compressed area to the stretched area in the material. If you think of the bent nanowire as an arch,
the atoms are moving from the inside of the arch to the outside. When the tension in the bent wire is released,
the atoms that simply moved closer or further apart snap back immediately; this is what we call elasticity.
But the atoms that moved out of position altogether take time to return to their original sites.
because it is much easier for atoms to move through nanoscale materials than through bulk materials.
And the atoms don't have to travel as far. In addition nanowires can be bent much further than thicker wires without becoming permanently deformed or breaking."
Here, we show that lignin nanoparticles infused with silver ions and coated with a cationic polyelectrolyte layer form a biodegradable and green alternative to silver nanoparticles.
The polyelectrolyte layer promotes the adhesion of the particles to bacterial cell membranes and, together with silver ions, can kill a broad spectrum of bacteria,
including Escherichia coli, Pseudomonas aeruginosa and quaternary-amine-resistant Ralstonia sp. Ion depletion studies have shown that the bioactivity of these nanoparticles is limited time because of the desorption of silver ions.
High-throughput bioactivity screening did not reveal increased toxicity of the particles when compared to an equivalent mass of metallic silver nanoparticles or silver nitrate solution.
Our results demonstrate that the application of green chemistry principles may allow the synthesis of nanoparticles with biodegradable cores that have higher antimicrobial activity and smaller environmental impact than metallic silver nanoparticles.
and environmentally benign method to combat bacteria by engineering nanoscale particles that add the antimicrobial potency of silver to a core of lignin,
NC State engineer Orlin Velev and colleagues show that silver-ion infused lignin nanoparticles, which are coated with a charged polymer layer that helps them adhere to the target microbes,
The remaining particles degrade easily after disposal because of their biocompatible lignin core, limiting the risk to the environment."
says that the particles could be the basis for reduced risk pesticide products with reduced cost and minimized environmental impact."
We are now working to scale up the process to synthesize the particles under continuous flow conditions."
harnessing its output for imaging applications that make microscopic particles appear huge.""The device makes an object super-visible by enlarging its optical appearance with this super-strong scattering effect,
Caltech researchers adopted a novel technique, ultrafast electron crystallography (UEC), to visualize directly in four dimensions the changing atomic configurations of the materials undergoing the phase changes.
"Today, nanosecond lasers--lasers that pulse light at one-billionth of a second--are used to record information on DVDS and Blu-ray disks,
Thus, with a nanosecond laser,"the fastest you can record information is one information unit
one 0 or 1, every nanosecond,"says Jianbo Hu, a postdoctoral scholar and the first author of the paper."
"To study this, the researchers used their technique, ultrafast electron crystallography. The technique, a new development--different from Zewail's Nobel prize-winning work in femtochemistry, the visual study of chemical processes occurring at femtosecond scales--allowed researchers to observe directly the transitioning atomic configuration of a prototypical phase-change
material, germanium telluride (Gete), when it is hit by a femtosecond laser pulse. In UEC, a sample of crystalline Gete is bombarded with a femtosecond laser pulse,
followed by a pulse of electrons. The laser pulse causes the atomic structure to change from the crystalline to other structures
Then, when the electron pulse hits the sample, its electrons scatter in a pattern that provides a picture of the sample's atomic configuration as a function of the time.
Hydrogen sensors are convertors that create electrical signal by adsorbing hydrogen molecules, which depends on the concentration of the hydrogen.
"We can start with a small molecule and build that into a nanoscale carrier that can seek out a tumor
The shell fragments form a ragged mesh that holds the drug molecules near the tumor.
As it turns out, a group of atoms essential to the drug molecule's effectiveness,
Gianneschi says they will broaden their approach to create delivery systems for other diagnostic and therapeutic molecules."
This novel approach to using enzyme-directed assembly of particle theranostics (EDAPT) is patent pending.
or distorting the wavefront--analogous to the quantum tunneling effect, in which a particle crosses through a potential energy barrier otherwise insurmountable by classical mechanics.
#Researchers Build a Transistor from a Molecule and A few Atoms A team of physicists from the Paul-Drude-Institut für Festkörperelektronik (PDI) and the Freie Universität Berlin (FUB), Germany, the NTT
and the U s. Naval Research Laboratory (NRL), United states, has used a scanning tunneling microscope to create a minute transistor consisting of a single molecule and a small number of atoms.
and could be important for future device technologies as well as for fundamental studies of electron transport in molecular nanostructures.
In atomic-scale transistors, this current is extremely sensitive to single electrons hopping via discrete energy levels.
Single-electron transport in molecular transistors has been studied previously using top-down approaches, such as lithography and break junctions.
The team used a highly stable scanning tunneling microscope (STM) to create a transistor consisting of a single organic molecule and positively charged metal atoms
to assemble electrical gates from the+1 charged atoms with atomic precision and, then, to place the molecule at various desired positions close to the gates.
Stefan Fölsch, a physicist at the PDI who led the team, explained that he molecule is only weakly bound to the Inas template.
So, when we bring the STM tip very close to the molecule and apply a bias voltage to the tip-sample junction,
single electrons can tunnel between template and tip by hopping via nearly unperturbed molecular orbitals,
similar to the working principle of a quantum dot gated by an external electrode. In our case, the charged atoms nearby provide the electrostatic gate potential that regulates the electron flow
and the charge state of the molecule But there is a substantial difference between a conventional semiconductor quantum dot comprising typically hundreds or thousands of atoms and the present case of a surface-bound molecule:
Steven Erwin, a physicist at NRL and expert in density-functional theory, pointed out that he molecule adopts different rotational orientations,
depending on its charge state. We predicted this based on first-principles calculations and confirmed it by imaging the molecule with the STM This coupling between charge
and orientation has a dramatic effect on the electron flow across the molecule, manifested by a large conductance gap at low bias voltages.
Piet Brouwer, a physicist at FUB and expert in quantum transport theory, said that his intriguing behavior goes beyond the established picture of charge transport through a gated quantum dot.
Instead we developed a generic model that accounts for the coupled electronic and orientational dynamics of the molecule This simple and physically transparent model entirely reproduces the experimentally observed single-molecule transistor characteristics.
The perfection and reproducibility offered by these STM-generated transistors will enable the exploration of elementary processes involving current flow through single molecules at a fundamental level.
Understanding and controlling these processes and the new kinds of behavior to which they can lead will be important for integrating molecule-based devices with existing semiconductor technologies.
The Paul-Drude-Institut für Festkörperelektronik (PDI) is a German research institute with about 100 employees located in Berlin-Mitte.
-Legislation/Regulation/Funding/Policy Researchers Build a Transistor from a Molecule and A few Atoms July 14th, 2015world first:
which relocates the electrons from a dark state to a luminescent state, thereby increasing the material ability to convert electrons into light particles, or photons.
With this technique, the multilayer Mos2 semiconductors are at least as efficient as monolayer ones. Duan team is currently moving forward to apply this approach to similar materials,
The one-atom-thick carbon sheets could revolutionize the way electronic devices are manufactured and lead to faster transistors, cheaper solar cells, new types of sensors and more efficient bioelectric sensory devices.
The method is based on an ion implantation technique, a process in which ions are accelerated under an electrical field and smashed into a semiconductor.
The impacting ions change the physical, chemical or electrical properties of the semiconductor. In a paper published this week in the journal Applied Physics Letters, from AIP Publishing,
the researchers describe their work, which takes graphene a step closer to commercial applications in silicon microelectronics."
"Our work shows that the carbon ion implantation technique has great potential for the direct synthesis of wafer-scale graphene for integrated circuit technologies."
carrying electrons with almost no resistance even at room temperature, a property known as ballistic transport. Graphene's unique optical, mechanical and electrical properties have lead to the one-atom-thick form of carbon being heralded as the next generation material for faster, smaller, cheaper and less power-hungry electronics."
"In silicon microelectronics, graphene is a potential contact electrode and an interconnection material linking semiconductor devices to form the desired electrical circuits,
"Kim's method relies on ion implantation, a microelectronics-compatible technique normally used to introduce impurities into semiconductors.
In the process, carbon ions were accelerated under an electrical field and bombarded onto a layered surface made of nickel, silicon dioxide and silicon at the temperature of 500 degrees Celsius.
Kim explained that the activation annealing temperature could be lowered by performing the ion implantation at an elevated temperature.
According to Kim, the ion implantation technique also offers finer control on the final structure of the product than other fabrication methods,
as the graphene layer thickness can be determined precisely by controlling the dose of carbon ion implantation.""Our synthesis method is controllable and scalable,
Plasmonics study suggests how to maximize production of'hot electrons'Abstract: New research from Rice university could make it easier for engineers to harness the power of light-capturing nanomaterials to boost the efficiency
including metallic nanoparticles that convert light into plasmons, waves of electrons that flow like a fluid across the particles'surface.
or nanostructure is that you can excite some subset of electrons in the metal to a much higher energy level,
"Scientists call these'hot carriers'or'hot electrons.'"'"Halas, Rice's Stanley C. Moore Professor of Electrical and Computer engineering and professor of chemistry, bioengineering, physics and astronomy,
and materials science and nanoengineering, said hot electrons are particularly interesting for solar-energy applications because they can be used to create devices that produce direct current
"He and Halas said Manjavacas, a theoretical physicist in the group of LANP researcher Peter Nordlander, conducted work in the new study that offers a fundamental insight into the underlying physics of hot-electron-production
"To make use of the photon's energy, it must be absorbed rather than scattered back out.
"From this perspective, one can determine the total number of electrons produced, but it provides no way of determining how many of those electrons are actually useful, high-energy, hot electrons,
"Manjavacas said. He said Zheng's data allowed a deeper analysis because his experimental setup selectively filtered high-energy hot electrons from their less-energetic counterparts.
To accomplish this, Zheng created two types of plasmonic devices. Each consisted of a plasmonic gold nanowire atop a semiconducting layer of titanium dioxide.
and allowed only hot electrons to pass from the gold to the semiconductor. The second setup allowed all electrons to pass."
"The experiment clearly showed that some electrons are hotter than others, and it allowed us to correlate those with certain properties of the system,
"Manjavacas said.""In particular, we found that hot electrons were correlated not with total absorption. They were driven by a different, plasmonic mechanism known as field-intensity enhancement."
"LANP researchers and others have spent years developing techniques to bolster the field-intensity enhancement of photonic structures for single-molecule sensing and other applications.
Zheng and Manjavacas said they are conducting further tests to modify their system to optimize the output of hot electrons.
Halas said, "This is an important step toward the realization of plasmonic technologies for solar photovoltaics.
Overtext Web Module V3.0 Alpha
Copyright Semantic-Knowledge, 1994-2011