which contain a central metal atom bound to several nitrogen-containing rings. Hemoglobin, which carries oxygen in the blood,
is a metalloporphyrin with iron as the central atom. For this sensor, the researchers used a metalloporphyrin with cobalt at its center.
STEVE The value measured by the 3d Cell Explorer is not fluorescence intensity of an exogenous molecule like with most optical microscopes.
#Quick, easy and early diagnosis with rare earth ions Lack of oxygen in cells is an indicator of diseases as serious as cerebral haemorrhages, stroke and cancer.
and we are getting pretty good at synthesizing the rare earth containing molecules. Before the year is out,
Previous experiments have seen molecules, which emit more light as the amount of oxygen diminishes. These, however, were incapable of measuring the amount of oxygen in cells,
whether a large amount of light signal was caused by a low oxygen concentration or a large concentration of oxygen sensitive molecules.
Sørensen's new molecule solves this problem because they have built a in control-function. The novel oxygen sensitive molecule is built with two rare earths,
so called lanthanides. One lanthanide, europium, emits a constant red signal. The other, terbium, emits a green signal that increases with diminishing oxygen concentrations.
Because Sørensen's molecules work by way of a simple colour shift they give a very exact indication of quantity as well as location of oxygen in a tissue sample or inside a cell.
scientists build artificial genes from individual molecules and then put these together to create larger genetic constructs which,
which rely on the drift and diffusion of electrons and their holes through semiconducting material, memristor operation is based on ionic movement,
The ionic memory mechanism brings several advantages over purely electron-based memories which makes it very attractive for artificial neural network implementation,
he said. ons are also much heavier than electrons and do not tunnel easily, which permits aggressive scaling of memristors without sacrificing analog properties.
#Researchers create first whispering gallery for graphene electrons (Nanowerk News) An international research group led by scientists at the U s. Commerce departments National Institute of Standards
and Technology (NIST) has developed a technique for creating nanoscale whispering galleries for electrons in graphene. The development opens the way to building devices that focus
and amplify electrons just as lenses focus light and resonators (like the body of a guitar) amplify sound.
issue of Science("Creating and probing electron whispering-gallery modes in graphene")."An international research group led by scientists at NIST has developed a technique for creating nanoscale whispering galleries for electrons in graphene.
The researchers used the voltage from a scanning tunneling microscope (right) to push graphene electrons out of a nanoscale area to create the whispering gallery (represented by the protuberances on the left),
which is like a circular wall of mirrors to the electron. Image: Jon Wyrick, CNST/NIST) In some structures,
such as the dome in St pauls Cathedral in London, a person standing near a curved wall can hear the faintest sound made along any other part of that wall.
These whispering galleries are unlike anything you see in any other electron based system, and thats really exciting.
However, early studies of the behavior of electrons in graphene were hampered by defects in the material.
When moving electrons encounter a potential barrier in conventional semiconductors it takes an increase in energy for the electron to continue flowing.
As a result, they are reflected often, just as one would expect from a ball-like particle.
However, because electrons can sometimes behave like a wave, there is a calculable chance that they will ignore the barrier altogether,
a phenomenon called tunneling. Due to the light-like properties of graphene electrons, they can pass through unimpededno matter how high the barrierif they hit the barrier head on.
This tendency to tunnel makes it hard to steer electrons in graphene. Enter the graphene electron whispering gallery.
To create a whispering gallery in graphene the team first enriched the graphene with electrons from a conductive plate mounted below it.
With the graphene now crackling with electrons, the research team used the voltage from a scanning tunneling microscope (STM) to push some of them out of a nanoscale-sized area.
This created the whispering gallery, which is like a circular wall of mirrors to the electron.
An electron that hits the step head-on can tunnel straight through it, said NIST researcher Nikolai Zhitenev.
But if electrons hit it at an angle, their waves can be reflected and travel along the sides of the curved walls of the barrier until they began to interfere with one another,
creating a nanoscale electronic whispering gallery mode. The team can control the size and strength, i e.,
, the leakiness, of the electronic whispering gallery by varying the STM tips voltage. The probe not only creates whispering gallery modes,
A team of theoretical physicists from the Massachusetts institute of technology developed the theory describing whispering gallery modes in graphene.
Working at the Center for Nanoscale Materials (CNM) and the Advanced Photon Source (APS), two DOE Office of Science User Facilities located at Argonne,
the team got membranes of gold nanoparticles coated with organic molecules to curl into tubes when hit with an electron beam.
Equally importantly they have discovered how and why it happens. The scientists coat gold nanoparticles of a few thousand atoms each with an oil-like organic molecule that holds the gold particles together.
When floated on water the particles form a sheet; when the water evaporates, it leaves the sheet suspended over a hole.
Its almost like a drumhead, says Xiao-Min Lin, the staff scientist at the Center for Nanoscale Materials who led the project.
The answer lay in the organic surface molecules. They are hydrophobic: when floated on water they try to avoid contact with it,
When the electron beam hits the molecules on the surface it causes them to form an additional bond with their neighbors,
Argonne researchers are able to fold gold nanoparticle membranes in a specific direction using an electron beam
or about six atoms thick, is so tiny it would not normally be measurable. Subramanian Sankaranarayanan and Sanket Deshmukh at CNM used the high-performance computing resources at DOES National Energy Research Scientific Computing Center and the Argonne Leadership Computing Facility (ALCF), both
They discovered that the amount of surface covered by the organic molecules and the molecules mobility on the surface both have an important influence on the degree of asymmetry in the membrane.
These are said fascinating results Fernando Bresme, professor of chemical physics at the Imperial College in London and a leading theorist on soft matter physics.
In principle, scientists could use this method to induce folding in any nanoparticle membrane that has an asymmetrical distribution of surface molecules.
You use one type of molecule that hates water and rely on the water surfaces to drive the molecules to distribute non-uniformly,
or you could use two different kinds of molecules. The key is that the molecules have to distribute non-uniformly.
The next step for Lin and his colleagues is to explore how they can control the molecular distribution on the surface and therefore the folding behavior.
They envision zapping only a small part of the structure with the electron beam, designing the stresses to achieve particular bending patterns.
You can maybe fold these things into origami structures and all sorts of interesting geometries,
As a conductor, graphene lets electrons zip too fasthere no controlling or stopping themhile boron nitride nanotubes are
so insulating that electrons are rebuffed like an overeager dog hitting the patio door. But together, these two materials make a workable digital switch
which is the basis for controlling electrons in computers, phones, medical equipment and other electronics. Yoke Khin Yap, a professor of physics at Michigan Technological University, has worked with a research team that created these digital switches by combining graphene and boron nitride nanotubes.
Nanoscale Tweaks Graphene is a molecule-thick sheet of carbon atoms; the nanotubes are made like straws of boron and nitrogen.
or differences in how much energy it takes to excite an electron in the material. hen we put them together,
you form a band gap mismatchhat creates a so-called otential barrierthat stops electrons. The band gap mismatch results from the materialsstructure:
caused by the difference in electron movement as currents move next to and past the hairlike boron nitride nanotubes.
These points of contact between the materialsalled heterojunctionsre what make the digital on/off switch possible. magine the electrons are like cars driving across a smooth track,
With their aligned atoms, the graphene-nanotube digital switches could avoid the issues of electron scattering. ou want to control the direction of the electrons,
slows down and redirects electrons. his is difficult in high speed environments, and the electron scattering reduces the number and speed of electrons.
Much like an arcade enthusiast, Yap says he and his team will continue trying to find ways to outsmart
or change the pinball setup of graphene to minimize electron scattering. And one day all their tweaks could make for faster computersnd digital pinball gamesor the rest of us t
and electrons in metal surfaces to develop novel components for optical data transmission between chips. The project is funded under the 7th Research Framework Programme of the European union
The team managed to synthesize a thin film made of densely packed aluminum oxide nanorods blended with molecules of a thrombolytic enzyme (urokinase-type plasminogen activator).
a ring of nine gamma ray bursts and hence galaxies-5 billion light years across. The scientists, led by Prof Lajos Balazs of Kokoly Observatory in Budapest,
-and ground-based observatories (see the Gamma ray Burst Online Index at http://www. astro. caltech. edu/grbox/grbox. php).
thrombin (a molecule at the centre of the clotting process) breaks open the outer layer of the nanocapsule,
By surrounding molecules of paclitaxel with self-assembling spheres composed of amino acids, the Duke team doubled tumor exposure to the drug compared to Abraxane
Its molecular structure is an atomic sandwich made up of one molybdenum atom for every two tellurium atoms HY1.
TMDS are molecules that can be made exceedingly thin, only several atomic layers, and have an electrical property called a band gap,
These atoms form a thin, molecular sandwich with the one metal and two chalcogenides, and depending on their fabrication method can exist in several slightly different shaped atomic arrangements.
As the chips approach single or several atom thickness, (commonly referred to as 2-dimensional),
which was several atoms thick. They directed a 1 m wide laser (a human hair is 17 to 181 m) at the 2h-Mote2
It enough a single pulse of laser, with a duration of several picoseconds the time of a single oscillation in a polar molecule, like water.
adding external molecules or binding compounds (functional groups like oxygen or hydroxyl. As the laser spot can be focused in areas of one square micron or less,
As recently published in AIP Applied Physics Letters("Patterned graphene ablation and two-photon functionalization by picosecond laser pulses in ambient conditions),
For low energy inputs, multiphoton absorption plays a major role, inducing chemical reactions between carbon and atmosphere molecules, resulting in new optical properties in graphene.
The potential of the altered optical properties (like spectral transmission) of functionalized graphene are just starting to be recognized,
#Integration of quantum dots and photonic crystals produce brighter, more efficient light Recently, quantum dots (QDS) ano-sized semiconductor particles that produce bright, sharp,
It consists of small clusters of four copper atoms each, supported on a thin film of aluminum oxide.
These catalysts work by binding to carbon dioxide molecules, orienting them in a way that is ideal for chemical reactions.
which limits how many atoms can catch and hold carbon dioxide.""With our catalyst, there is no inside,
"All four copper atoms are participating because with only a few of them in the cluster,
the current method of reduction creates high-pressure conditions to facilitate stronger bonds with carbon dioxide molecules.
"For this research, the team used the Center for Nanoscale Materials as well as beamline 12-ID-C of the Advanced Photon Source, both DOE Office of Science User Facilities.
Curtiss said the Advanced Photon Source allowed the scientists to observe ultralow loadings of their small clusters, down to a few nanograms,
In addition, as an actual needle application, we demonstrated fluorescenctce particle depth injection into the brain in vivo,
and probe biological molecules to explore their potential use as new drugs. The device has the potential to replace gold nanodevices used in current analytical techniques,
including investigating individual biochemical reactions and detecting molecules such as contaminants or explosives at extremely low concentrations.
because they have the ability to capture individual photons of light. When fashioned into certain shapes, with specifically patterned surfaces,
they can channel photons along their surface, focusing their energy into a tight spot. When the material is a metal,
or the development of silicon computing chips that process data communicated by photons of light instead of electricity.
Common laboratory analytical techniques such as Raman and fluorescence spectroscopy determine the properties of biological molecules,
"Information built up from the way focused light scatters off a complex molecule can be used to determine something about its composition
"Amongst other things, this information can help to predict how the molecules might interact with biochemical processes in living cells,
because they are relatively cheap and easy to fashion into the right shapes needed to channel photons the right way.
"The cloud of free-moving electrons around a metal that carries an electrical current can also absorb passing photons.
but their electrons absorb fewer passing photons.""While this extremely localised and directed heating effect has been put to some good uses like targeting cancerous cells to kill them,
Control voltages that shift oxygen ions and vacancies switch the bits between ones and zeroes.
the researchers found the tantalum oxide gradually loses oxygen ions, changing from an oxygen-rich, nanoporous semiconductor at the top to oxygen-poor at the bottom.
First, the control voltage mediates how electrons pass through a boundary that can flip from an ohmic (current flows in both directions) to a Schottky (current flows one way) contact and back.
These are"holes"in atomic arrays where oxygen ions should exist, but don't. The voltage-controlled movement of oxygen vacancies shifts the boundary from the tantalum/tantalum oxide interface to the tantalum oxide/graphene interface."
Third, the flow of current draws oxygen ions from the tantalum oxide nanopores and stabilizes them.
These negatively charged ions produce an electric field that effectively serves as a diode to hinder error-causing crosstalk.
A defect-free layer is also impermeable to all atoms and molecules. This amalgamation makes it a terrifically attractive material to apply to scientific developments in a wide variety of fields, such as electronics, aerospace and sports.
"We transferred electrons from the dopant-potassium-to the surface of the black phosphorus, which confined the electrons
and allowed us to manipulate this state. Potassium produces a strong electrical field which is required what we to tune the size of the band gap."
"This process of transferring electrons is known as doping and induced a giant Stark effect, which tuned the band gap allowing the valence
Now, researchers from the University of Bristol in the UK and Nippon Telegraph and Telephone (NTT) in Japan, have pulled off the same feat for light in the quantum world by developing an optical chip that can process photons in an infinite number
which are typically extremely demanding due to the notoriously fragile nature of quantum systems. This result shows a step change for experiments with photons
and what the future looks like for quantum technologies. Dr Anthony Laing, who led the project,
Now anybody can run their own experiments with photons, much like they operate any other piece of software on a computer.
The conjecture is that this arises from an avalanche of electrons from the top surface of the film to the bottom,
where the electrons are confined near the substrate. This shift of electric charge occurs as the manganese atomic layers form atomically charged capacitors leading to the build up of an electric field, known as polar catastrophe
Each new combination of atom-thick layers presents new properties and researchers suspect that one, or more, of these new materials will exhibit energy storage
the researchers selectively extract layers of aluminum atoms from a block of MAX phase by etching them out with an acid."
where the titanium atoms are in center and the molybdenum on the outside. The next Frontier Now, with the help of theoretical calculations done by researchers at the FIRST ENERGY Frontier Research center at the Oak ridge National Laboratory,
replacing up to 25 percent of the lanthanum ions in the host material with strontium ions, offers considerable promise.
Of particular importance are new materials that conduct electricity by using missing electrons, otherwise known as"holes."
Although electron conducting (n-type) TCOS are presently in use in many devices, their hole-conducting (p-type) counterparts have not been commercialized as candidate materials
and elsewhere using a technique called spin-polarized neutron reflectometry. They say the new finding could be used to probe a variety of exotic physical phenomena,
Possible applications of the new findings include the creation of spintronics, transistors based on the spin of particles rather than their charge.
These are expected to have low energy dissipation if based on topological insulators, and are a very active area of research.
This includes the study of predicted physical phenomena such as Majorana fermions, particles predicted in 1937 but not yet observed, which,
unlike all known subatomic particles, serve as their own antiparticles. These theorized particles ave yet to be explored.
It opens another avenue to explore these things he says. he significance of this work is threefold,
says Qi-Kun Xue, a professor of physics at Tsinghua University in China who was involved not in this work.
#Information storage and retrieval in a single levitating colloidal particle Thanks to this new technique developed by scientists at the University of Zurich,
'click on image to enlarge) Colloids are minute particles that are distributed finely throughout a liquid.
Suspensions of colloidal particles are most familiar to us as beverages, cosmetics and paints. At a diameter in the range of ten to one hundred nanometres, a single such particle is invisible to the naked eye.
These nanoparticles are constantly in motion due to the principle of Brownian motion. Since the particles are charged electrically,
they experience forces of attraction and repulsion that can be harnessed to control and manipulate their behavior.
In experiments carried out five years ago, Madhavi Krishnan Professor of Physical chemistry at the University of Zurich, succeeded in the controlled spatial manipulation of matter on the nanometer scale.
They were able to organise the tiny particles into new structures with the utmost precision
and each individual particle can now be used to store and retrieve data, "explains Madhavi Krishnan.
#Electrons that stick together, superconduct together The discovery of a surprising feature of superconductivity in an unconventional superconductor by a RIKEN-led research team provides clues about the superconducting mechanism in this material
Superconductivity occurs as the result of pairs of electrons binding together in such a way that they act as a single quasiparticle.
the binding force is provided by vibrations in the atomic lattice through which the electrons travel.
or spin fluctuation of the electrons themselves, which binds electrons in pairs through the entanglement of electron spins.
However recent experiments have shown that this mechanism cannot explain the superconducting state in the quintessential unconventional superconductor Cecu2si2.
Inspired by this result, Michi-To Suzuki and Ryotaro Arita from the RIKEN Center for Emergent Matter Science, in collaboration with Hiroaki Ikeda from Ritsumeikan University in Japan, investigated the mechanism of electron pairing in 2si2
The electrons in Cecu2si2 can interact by entanglement of both spin and orbital states, resulting in multiple possible configurations or degrees of freedom.
but to their surprise, the researchers found that multipole fluctuations can also produce bound pairs of electrons,
This kind of electron binding may also be present in the recently discovered class of high-temperature iron-based superconductors. e found that the origin of the unconventional superconductivity in Cecu2si2 is an exotic multipole degree of freedom consisting of entangled spins
and have applications in superresolution microscopy, laser cutting, and particle acceleration.""You generally would need a large optical setup,
"The team is currently working with industrial partners to create metasurfaces for use in commercial devices such as miniature cameras and spectrometers,
#Quantum dot solar cell exhibits 30-fold concentration We've achieved a luminescent concentration ratio greater than 30 with an optical efficiency of 82-percent for blue photons,
and photonic mirrors suffer far less parasitic loss of photons than LSCS using molecular dyes as lumophores.
and reabsorption and scattering of propagating photons. We replaced the molecular dyes in previous LSC systems with core/shell nanoparticles composed of cadmium selenide (Cdse) cores
while reducing photon re-absorption, says Bronstein. The Cdse/Cds nanoparticles enabled us to decouple absorption from emission energy and volume,
This approach captures complex, nonlinear interactions of molecules on metal surfaces through artificial neural networks, thus allowing arge scale exploration alloy materials space, according to their article.
they have identified a few promising copper multi-metallics with a higher energy conversion efficiency and possibly higher selectivity in carbon dioxide electro-reduction to ethylene,
"Carbon nanotubes are rolled-up arrays of perfect hexagons of atoms; graphene is a rolled out sheet of the same.
and excel at transmitting electrons and heat. But when the two are joined, the way the atoms are arranged can influence all those properties. ome labs are actively trying to make these materials or measure properties like the strength of single nanotubes and graphene sheets,
Shahsavari said. ut we want to see what happens and quantitatively predict the properties of hybrid versions of graphene and nanotubes.
or lose atoms to neighboring rings, depending on how they join with their neighbors. By forcing five, seven or even eight-atom rings
they found they could gain a measure of control over the hybrid mechanical properties. Turning the nanotubes in a way that forced wrinkles in the graphene sheets added further flexibility and shear compliance,
with their atoms arranged in a highly organised and regular manner. Metallic glass alloys, however, have disordered a highly structure,
with the atoms arranged in a non-regular way.""There are many types of metallic glass, with the most popular ones based on zirconium, palladium, magnesium, titanium or copper.
#Physicists discover spiral vortex patterns from electron waves In their new study("Electron Vortices in Photoionization by Circularly Polarized Attosecond Pulses),
when an electron is ejected, or ionized, from its orbit around a helium atom. Like all subatomic particles, electrons occupy a realm governed by quantum mechanics.
This means that their position, velocity and other properties are probabilistic, existing within a range of possible values.
Electrons can also exhibit the behavior of waves that, like ripples in a pond often gain or lose amplitude as they cross paths.
By firing two time-delayed, ultrashort laser pulses at a helium atom, the researchers found that the distribution of momentum values for these intersecting electron waves can take the form of a two-armed vortex that resembles a spiral galaxy.
Though the spiral had been observed in waves of light, the team study is the first to produce the pattern with electrons.
In doing so, it also dramatically demonstrates the wavelike property of matter, Starace said. Starace called the pattern an xcellent diagnostic toolfor characterizing electron-manipulating laser pulses
which occur on such fast time scales that physicists have sought multiple ways to measure their durations and intensities.
whereas the duration of the pulses corresponds to the width of the arms. f you use (longer) pulses to probe the electrons,
Current transistors consist of only a handful of atoms. It is a major challenge to produce chips in
with a flick of a switch and a temperature jump, make a huge range of biological molecules that either assemble or disassemble."
#Physicists determine the three-dimensional positions of individual atoms for the first time Atoms are the building blocks of all matter On earth,
Now, scientists at UCLA have used a powerful microscope to image the three-dimensional positions of individual atoms to a precision of 19 trillionths of a meter,
to infer the macroscopic properties of materials based on their structural arrangements of atoms, which will guide how scientists and engineers build aircraft components, for example.
a UCLA professor of physics and astronomy and a member of UCLA California Nanosystems Institute, is published Sept. 21 in the online edition of the journal Nature Materials("Three-dimensional coordinates of individual atoms
in materials revealed by electron tomography")."For more than 100 years, researchers have inferred how atoms are arranged in three-dimensional space using a technique called X-ray crystallography,
which involves measuring how light waves scatter off of a crystal. However, X-ray crystallography only yields information about the average positions of many billions of atoms in the crystal,
and not about individual atomsprecise coordinates. t like taking an average of people On earth, Miao said. ost people have a head, two eyes, a nose and two ears.
Because X-ray crystallography doesn reveal the structure of a material on a per-atom basis
the technique can identify tiny imperfections in materials such as the absence of a single atom.
which a beam of electrons smaller than the size of a hydrogen atom is scanned over a sample
and measures how many electrons interact with the atoms at each scan position. The method reveals the atomic structure of materials
because different arrangements of atoms cause electrons to interact in different ways. However scanning transmission electron microscopes only produce two-dimensional images.
The downside of this technique is repeated that the electron beam radiation can progressively damage the sample.
the researchers were able to slowly assemble a 3-D model of 3, 769 atoms in the tip of the tungsten sample.
The researchers compared the images from the first and last scans to verify that the tungsten had not been damaged by the radiation
thanks to the electron beam energy being kept below the radiation damage threshold of tungsten. Miao and his team showed that the atoms in the tip of the tungsten sample were arranged in nine layers, the sixth
of which contained a point defect. The researchers believe the defect was either a hole in an otherwise filled layer of atoms
or one or more interloping atoms of a lighter element such as carbon. Regardless of the nature of the point defect, the researchersability to detect its presence is significant,
demonstrating for the first time that the coordinates of individual atoms and point defects can be recorded in three dimensions. e made a big breakthrough,
Miao said. Miao and his team plan to build on their results by studying how atoms are arranged in materials that possess magnetism or energy storage functions,
which will help inform our understanding of the properties of these important materials at the most fundamental scale. think this work will create a paradigm shift in how materials are characterized in the 21st century,
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