"This is the first time that synthetic accessory molecules have been engineered to change the specificity of an enzyme
but one can envision applications of this concept with enzymes acting on other types of molecules such as lipids
and binding specific target molecules, termed substrates. Some enzymes combine substrates into a new molecule,
such as those that synthesize strands of DNA from nucleic acids. Others break apart substrates into multiple products, such as ones that break down starch into sugars.
monobodies can be designed to bind with pinpoint precision to desired positions within a target molecule such as an enzyme.
This enzyme builds chains of sugar molecules by adding individual sugar units to existing chains.
Gartner's team makes use of a familiar molecule: DNA. The researchers incubate cells with tiny snippets of single stranded-dna DNA engineered to slip into the cells'outer membranes, covering each cell like the hairs on a tennis ball.
Prp prions in the dangerous, misfolded form latch on to other nearby Prp molecules, causing them to lose their normal shape
a molecule found in bacteria that can make an animal sick without being contagious. The researchers saw that the disrupted animals had blunted immune responses in some cases
"The investigators say they are currently testing an oral small molecule immune modulator in phase 2 clinical trials that acts like volatile anesthetics to help reduce secondary infections after someone becomes sick with the flu u
#Ideal single-photon source developed With the help of a semiconductor quantum dot, physicists have developed a new type of light source that emits single photons.
For the first time, the researchers have managed to create a stream of identical photons. They have reported their findings in the scientific journal Nature Communications together with colleagues from the University of Bochum.
A single-photon source never emits two or more photons at the same time. Single photons are important in the field of quantum information technology where, for example,
they are used in quantum computers. Alongside the brightness and robustness of the light source the indistinguishability of the photons is especially crucial.
In particular, this means that all photons must be the same color. Creating such a source of identical single photons has proven very difficult in the past.
However, quantum dots made of semiconductor materials are offering new hope. A quantum dot is a collection of a few hundred thousand atoms that can form itself into a semiconductor under certain conditions.
Single electrons can be captured in these quantum dots and locked into a very small area. An individual photon is emitted
when an engineered quantum state collapses. Noise in the semiconductor A team of scientists led by Dr. Andreas Kuhlmann and Prof.
Richard J. Warburton from the University of Basel have shown already in past publications that the indistinguishability of the photons is reduced by the fluctuating nuclear spin of the quantum dot atoms.
For the first time ever, the scientists have managed to control the nuclear spin to such an extent that even photons sent out at very large intervals are the same color.
Quantum cryptography and quantum communication are two potential areas of application for single-photon sources.
These technologies could make it possible to perform calculations that are far beyond the capabilities of today's computers.
The study was supported by the QSIT-Quantum Science and Technology National Center of Competence in Research
of which the University of Basel is the co-leading house e
#Study creates cell immunity to parasite that infects 50 million There are two common approaches to protecting humans from infectious disease:
University of British columbia (UBC) physicists have been able to create the first ever superconducting graphene sample by coating it with lithium atoms.
Although superconductivity has already been observed in intercalated bulk graphite--three-dimensional crystals layered with alkali metal atoms,
"Decorating monolayer graphene with a layer of lithium atoms enhances the graphene's electron-phonon coupling to the point where superconductivity can be induced,
"Decorating monolayer graphene with a layer of lithium atoms enhances the graphene's electron-phonon coupling to the point where superconductivity can be stabilized."
University of British columbia (UBC) physicists have been able to create the first ever superconducting graphene sample by coating it with lithium atoms.
Although superconductivity has already been observed in intercalated bulk graphite--three-dimensional crystals layered with alkali metal atoms,
"Decorating monolayer graphene with a layer of lithium atoms enhances the graphene's electron-phonon coupling to the point where superconductivity can be induced,
"Decorating monolayer graphene with a layer of lithium atoms enhances the graphene's electron-phonon coupling to the point where superconductivity can be stabilized."
#New molecule found to prevent preterm birth Premature births are linked intimately with inflammation of the uterine tissue, a biological response
"Orthosteric antagonists currently available on the market are large molecules. They block most of the signaling pathways of Interleukin 1,
in addition to being safer than the existing molecules designed for the same target.""The allosteric modulators that we have developed work differently.
Our molecule is very small, "says enthusiastically Dr. Sylvain Chemtob, a neonatologist and investigator, and the lead author of the study who developed the molecule in collaboration with his research associate Christiane Quiniou, Ph d. and Dr William Lubell, professor of chemistry at University of Montreal)."
"The small size of the molecule allows it to act more selectively on Interleukin 1. It specifically blocks the pathway that controls inflammation without interfering with those
which exert a protective effect on the immune system and the cells.""""101.10,"as the scientists have named their molecule,
now needs to be tested in humans. For the time being, women with a history of prematurity would be candidate for this future treatment,
Phosphonates are an abundant and diverse class of natural signaling molecules that have already proved useful to medicine and agriculture
"These biologically produced small molecules have been the source of, or inspiration for, nearly two-thirds of all human medicines, yet research in this area has dwindled in recent years due to, among other reasons, high costs and increasing rates of rediscovery,
#Nano-dunes with the ion beam Many semiconductor devices in modern technology--from integrated circuits to solar cells and LEDS--are based on nanostructures.
for self-organization of nanostructured arrays via broad ion beam irradiation. The results have been published in the scientific journal Nanoscale.
the researchers use ion beams, which are charged fast, electrically atoms. They direct a broad beam of noble gas ions onto a gallium arsenide wafer, which,
for example, is used in producing high-speed and high-frequency transistors, photocells or light-emitting diodes.""One could compare ion bombardment with sand blasting.
This means that the ions mill off the surface of the target. There, the desired nanostructures are created all by themselves,
"explains Dr. Facsko. The finely chiselled and regular structure is reminiscent of sand dunes, natural structures created by wind.
It all occurs, however, in a nano-realm, with a mere distance of fifty nanometers between two dunes--strands of human hair are two thousand times thicker.
Ion Bombardment at Elevated Temperature At room temperature, however, the ion beam destroys the crystal structure of the gallium arsenide and thus its semiconducting properties.
Dr. Facsko's group at the HZDR's Ion beam Center therefore uses the opportunity to heat the sample during ion bombardment.
At about four hundred degrees Celsius, the destroyed structures recover rapidly. A further effect ensures that the nano-dunes on the semiconductor surface develop.
The colliding ions not only shift the atoms they hit, but also knock individual atoms entirely out of the crystal structure.
Since the volatile arsenic does not remain bound on the surface, the surface soon consists only of gallium atoms.
In order to compensate for the missing arsenic atom bonds, pairs of two gallium atoms form, which arrange themselves in long rows.
If the ion beam knocks out further atoms next to them, the gallium pairs cannot slip down the step that has been created
because the temperatures are too low for this to happen. This is how the long rows of gallium pairs form nano-dunes after a period of time, in
which several long pairs of lines lie next to each other. Many experiments at different temperatures and comprehensive computations were necessary to both preserve the crystalline state of the semiconducting material as well to produce the well-defined structures at the nanoscale.
Because we use particularly low energy ions--under 1 kilovolt, -which can be generated using simple methods,
"We're good at generating electrons from light efficiently, but chemical synthesis always limited our systems in the past.
"We're good at generating electrons from light efficiently, but chemical synthesis always limited our systems in the past.
#First realization of an electric circuit with a magnetic insulator using spin waves Researchers at the University of Groningen, Utrecht University,
The circuit is realized using spin waves: wavelike perturbations in the magnetic properties of a material.
A device based on spin waves could theoretically operate more efficiently than ordinary electronic circuits. The results of their research will be published online in Nature Physics on Monday 14 september.
In our current electronic equipment, information is transported via the motion of electrons. In this scheme, the charge of the electron is used to transmit a signal.
In a magnetic insulator, a spin wave is used instead. Spin is a magnetic property of an electron.
A spin wave is caused by a perturbation of the local magnetisation direction in a magnetic material.
Such a perturbation is caused by an electron with an opposite spin, relative to the magnetisation.
Spin waves transmit these perturbations in the material. This research demonstrates for the first time that it is possible to transmit electric signals in an insulating material.
Strong perturbation So far, electrical circuits based on spin waves have not been realised, since it turned out to be impossible to introduce a perturbation in the system large enough to create spin waves.
FOM workgroup leader prof. dr. Bart van Wees and his Phd student Ludo Cornelissen, both from the University of Groningen and FOM workgroup leader dr. Rembert
Duine from Utrecht University have succeeded to use spin waves in an electric circuit by carefully designing the device geometry.
This allows them to make use of the spin waves that are already present in the material due to thermal fluctuations,
which requires a much smaller disturbance of the system and hence enables the spin waves to be used in an electric circuit.
The spin wave circuit that the researchers built, consists of a 200 nanometre thin layer of yttrium iron garnet (a mineral and magnetic insulator, YIG in short), with a conducting platinum strip on top of that on both sides.
An electron can flow through the platinum, but not in the YIG since it is an insulator.
However, if the electron collides on the interface between YIG and platinum this influences the magnetisation at the YIG surface and the electron spin is transferred.
This causes a local magnetisation direction, generating a spin wave in the YIG. Spin wave detection The spin waves that the researchers send into the YIG are detected by the platinum strip on the other side of the YIG.
The detection process is exactly opposite to the spin wave injection: a spin wave collides at the interface between YIG and platinum,
and transfers its spin to an electron in the platinum. This influences the motion of the electron, resulting in an electric current that the researchers can measure.
The researchers already studied the combination of platinum and YIG in previous research. From this research it was found that
when spin is transferred from platinum to YIG, this also implies the transfer of heat across the interface.
This enables the heating or cooling of the platinum-YIG interface, depending on the relative orientation of the electron spins in the platinum and the magnetisation in the YIG I
#Key component for terahertz wireless networks Terahertz radiation could one day provide the backbone for wireless systems that can deliver data up to one hundred times faster than today's cellular or Wi-fi networks.
But there remain many technical challenges to be solved before terahertz wireless is ready for prime time.
Researchers from Brown University have taken a major step toward addressing one of those challenges. They've developed
what they believe to be the first system for multiplexing terahertz waves. Multiplexers are devices that enable separate streams of data to travel through a single medium.
It's the technology that makes it possible for a single cable to carry multiple TV channels
or for a fiber optic line to carry thousands of phone calls at the same time.""Any terahertz communications application is going to need some form of multiplexing
As terahertz waves travel down the waveguide, some of the radiation leaks out of the slit.
"On the other end, a receiver could be tuned to accept radiation at a particular angle,
#Building the electron superhighway TV screens that roll up. Roofing tiles that double as solar panels. Sun powered cell phone chargers woven into the fabric of backpacks.
But the basic science of how to get electrons to move quickly and easily in these organic materials remains murky.
what they are calling"an electron superhighway"in one of these materials--a low-cost blue dye called phthalocyanine--that promises to allow electrons to flow faster and farther in organic semiconductors Their discovery,
"Roughly speaking, an exciton is displaced a electron bound together with the hole it left behind.
the UVM team was able to observe nanoscale defects and boundaries in the crystal grains in the thin films of phthalocyanine--roadblocks in the electron highway."
"We have discovered that we have hills that electrons have to go over and potholes that they need to avoid,
The new technique allows the scientists a deeper understanding of how the arrangement of molecules
"The molecules are stacked like dishes in a dish rack, "Furis explains, "these stacked molecules--this dish rack--is the electron superhighway."
"Though excitons are charged neutrally --and can't be pushed by voltage like the electrons flowing in a light bulb--they can, in a sense, bounce from one of these tightly stacked molecules to the next.
This allows organic thin films to carry energy along this molecular highway with relative ease,
"One could describe it as a flight simulator of quantum physics, "says Mathias Tomandl who designed and implemented the essential elements of the simulation in the course of his Phd studies.
Discovering the quantum world--step by step A learning path guides the visitors of the virtual quantum lab through the world of delocalized complex molecules.
Wave-particle dualism with large molecules The virtual laboratories provide an insight into the fundamental understanding and into the applications of quantum mechanics with macromolecules and nanoparticles.
In recent years, the real-life versions of the experiments verified the wave-particle dualism with the most complex molecules to date.
#Tiny silica particles could be used to repair damaged teeth, research shows Researchers at the University of Birmingham have shown how the development of coated silica nanoparticles could be used in restorative treatment of sensitive teeth
The study, published in the Journal of Dentistry, shows how sub-micron silica particles can be prepared to deliver important compounds into damaged teeth through tubules in the dentine.
The tiny particles can be bound to compounds ranging from calcium tooth building materials to antimicrobials that prevent infection.
with the particles acting like seeds for further growth that would close the tubules. Previous attempts have used compounds of calcium fluoride, combinations of carbonate-hydroxypatite nanocrystals and bioactive glass,
However, the Birmingham team turned to sub-micron silica particles that had been prepared with a surface coating to reduce the chance of aggregation.
When observed using high definition SEM (Scanning Electron Microsopy the researchers saw promising signs that suggested that the aggregation obstacle had been overcome.
"These silica particles are available in a range of sizes, from nanometre to sub-micron,
""We tested a number of different options to see which would allow for the highest level particle penetration into the tubules,
and then see how effective the particles are blocking the communication with the inside of the tooth.
Deleon and her UD team have identified particles in the secretions from the fallopian tube that help the sperm get ready for its all-important drive into the end zone.
can illuminate what's happening in a cell, right down to a single molecule. The oviductosomes from a female mouse were labeled pre with a fluorescent dye
along with fusion stalks on the sperm's surface.""Discovery of these oviductosomes provides us with a window into the cargo being delivered by the female to the sperm,
"We've shown that these oviductosomes are carrying critical molecules that include not only proteins, but also nucleic acids such as RNA and also lipids,"Deleon says."
While the individual atoms in a natural material cannot be rearranged with pinpoint precision on such a grand scale,
The long-range order of water molecules increases in a similar way at the moment when water freezes into ice.""We were fascinated by the fact that our synthetic material displayed this everyday phenomenon of a phase transition,
supplies beams from exotic elementary particles called muons, which can be used to study nanomagnetic properties. The project took place in collaboration with a research group headed by Stephen Lee from the University of St andrews, Scotland n
France have succeeded in developing a vaginal silicone ring that delivers molecules that act on both HIV and herpes virus.
"We succeeded in creating a ring that can deliver hydrophilic molecules such as tenofovir, active on HIV-1,
but was capable of delivering multiple active antiviral molecules against various STIS including HIV for a long duration,
#Physicists determine 3-D 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.
For more than 100 years, researchers have inferred how atoms are arranged in three-dimensional space using a technique called X-ray crystallography,
However, X-ray crystallography only yields information about the average positions of many billions of atoms in the crystal
and not about individual atoms'precise coordinates.""It's like taking an average of people On earth,
"Because X-ray crystallography doesn't reveal the structure of a material on a per-atom basis,
the technique can't 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.
769 atoms in the tip of the tungsten sample. The experiment was time consuming because the researchers had to wait several minutes after each tilt for the setup to stabilize."
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 researchers'ability 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."
"We 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."
The emitted radiation is fully coherent and emitted 100 million times per second. Each laser pulse has a duration of 66 fs
and cools it in a way that allows it to convert more photons into electricity. The work by Shanhui Fan, a professor of electrical engineering at Stanford, research associate Aaswath P. Raman and doctoral candidate Linxiao Zhu is described in the current issue of Proceedings of the National Academy
the less efficient they become at converting the photons in light into useful electricity. The Stanford solution is based on a thin,
but captures and emits thermal radiation, or heat, from infrared rays.""Solar arrays must face the sun to function,
"We call this a smart particle, "said James Swartz, the professor of chemical engineering and of bioengineering at Stanford who led the study."
"Using the smart particle for immunotherapy would involve tagging its outer surface with molecules designed to teach the body's disease-fighting cells to recognize
It will require much more effort to accomplish the second goal--packing tiny quantities of medicines into the smart particles,
delivering the particles to and into diseased cells, and engineering them to release their payloads.'
"But I believe we can use this smart particle to deliver cancer-fighting immunotherapies that will have minimal side effects."
"Dr. Swartz and colleagues have done a remarkable job of stabilizing viruslike particles and re-engineering their surface."
radiation or chemotherapies harm healthy cells while treating cancer. Looking for a model in nature, many researchers focused on viruses,
The new paper describes how the Stanford team designed a viruslike particle that is only a delivery vehicle with no infectious payload.
Swartz said the next step is to attach cancer tags to the outside of this smart particle,
with a flick of a switch and a temperature jump, make a huge range of biological molecules that either assemble or disassemble."
Among the substances they tested was a synthetic, small-molecule compound known as PF-04554787. During lab testing, the compound"markedly inhibited"the growth of three human pancreatic cancer cell lines five days after treatment
Phase change materials that change their optical properties depending on the arrangement of the atoms allow for the storage of several bits in a single cell.
novel materials that change their optical properties depending on the arrangement of the atoms: Within shortest periods of time, they can change between crystalline (regular) and amorphous (irregular) states.
"or transferred quantum information carried in light particles over 100 kilometers (km) of optical fiber, four times farther than the previous record.
including one at NIST using atoms in 2004. Arraythe lead author, Hiroki Takesue, was a NIST guest researcher from NTT Corp. in Japan.
The achievement was made possible by advanced single-photon detectors designed and made at NIST.""Only about 1 percent of photons make it all the way through 100 km of fiber,
"NIST's Marty Stevens says.""We never could have done this experiment without these new detectors,
"Previously, researchers thought quantum repeaters might need to rely on atoms or other matter, instead of light,
when in a sequence of time slots a single photon arrives. The teleportation method is novel in that four of NIST's photon detectors were positioned to filter out specific quantum states.
The detectors rely on superconducting nanowires made of molybdenum silicide. They can record more than 80 percent of arriving photons,
revealing whether they are in the same or different time slots each just 1 nanosecond long.
The experiments were performed at wavelengths commonly used in telecommunications. Because the experiment filtered out and focused on a limited combination of quantum states
freestanding 2d sheets through such techniques as spin-coating, chemical vapor deposition, and mechanical exfoliation has met with limited success. In 1994,
which harness the science of the very small--the strange behaviour of subatomic particles--to solve computing challenges that are beyond the reach of even today's fastest supercomputers.
"We've morphed those silicon transistors into quantum bits by ensuring that each has only one electron associated with it.
We then store the binary code of 0 or 1 on the'spin'of the electron,
which is associated with the electron's tiny magnetic field, "he added. Dzurak noted that that the team had patented recently a design for a full-scale quantum computer chip that would allow for millions of our qubits,
or ion channels, each of which is a portal for specific ions. Ion channels are typically about 1 nanometer wide;
by maintaining the right balance of ions, they keep cells healthy and stable. Now researchers at MIT have created tiny pores in single sheets of graphene that have an array of preferences and characteristics similar to those of ion channels in living cells.
which scientists have studied ever ion flow. Each is also uniquely selective, preferring to transport certain ions over others through the graphene layer."
"What we see is that there is a lot of diversity in the transport properties of these pores,
detecting ions of mercury, potassium, or fluoride in solution. Such ion-selective membranes may also be useful in mining:
In the future, it may be possible to make graphene nanopores capable of sifting out trace amounts of gold ions from other metal ions, like silver and aluminum.
Karnik and former graduate student Tarun Jain, along with Benjamin Rasera, Ricardo Guerrero, Michael Boutilier, and Sean O'Hern from MIT and Juan-carlos Idrobo from Oak ridge National Laboratory, publish their results in the journal Nature Nanotechnology.
which are slightly smaller than the ions that flow through them.""When nanopores get smaller than the hydrated size of the ion,
then you start to see interesting behavior emerge, "Jain says. In particular, hydrated ions, or ions in solution, are surrounded by a shell of water molecules that stick to the ion,
depending on its electrical charge. Whether a hydrated ion can squeeze through a given ion channel depends on that channel's size and configuration at the atomic scale.
Karnik reasoned that graphene would be a suitable material in which to create artificial ion channels:
A sheet of graphene is an ultrathin lattice of carbon atoms that is one atom thick, so pores in graphene are defined at the atomic scale.
To create pores in graphene, the group used chemical vapor deposition, a process typically used to produce thin films.
The researchers then isolated individual pores by placing each graphene sheet over a layer of silicon nitride that had been punctured by an ion beam
The group reasoned that any ions flowing through the two-layer setup would have passed likely first through a single graphene pore,
The group measured flows of five different salt ions through several graphene sheet setups by applying a voltage and measuring the current flowing through the pores.
and from ion to ion, with some pores remaining stable, while others swung back and forth in conductance--an indication that the pores were diverse in their preferences for allowing certain ions through."
"The picture that emerges is that each pore is different and that the pores are dynamic,
which--given the single-atom thickness of graphene--makes them among the smallest pores through
which scientists have studied ion flow. With the model, the group calculated the effect of various factors on pore behavior,
Knowing this, researchers may one day be able to tailor pores at the nanoscale to create ion-specific membranes for applications such as environmental sensing and trace metal mining."
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