Space is a constant reminder of how little we truly know about our universe. A new international project is hoping to help make a little more sense of things. Next year, researchers from 13 countries will launch a balloon to, hopefully, find high-energy particles that couldn’t have come from Earth.
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Continue reading “The Physics of Self-Replication and Nanotechnology” »
Osaka Metropolitan University scientists have developed a simple, rapid method to simultaneously identify multiple food poisoning bacteria, based on color differences in the scattered light by nanometer-scaled organic metal nanohybrid structures (NHs) that bind via antibodies to those bacteria. This method is a promising tool for rapidly detecting bacteria at food manufacturing sites and thereby improving food safety. The findings were published in Analytical Chemistry.
According to the World Health Organization (WHO), every year food poisoning affects 600 million people worldwide—almost 1 in every 10 people—of which 420,000 die. Bacterial tests are conducted to detect food poisoning bacteria at food manufacturing factories, but it takes more than 48 hours to obtain results due to the time required for a bacteria incubation process called culturing. Therefore, there remains a demand for rapid testing methods to eliminate food poisoning accidents.
Responding to this need, the research team led by Professor Hiroshi Shiigi at the Graduate School of Engineering, Osaka Metropolitan University, utilized the optical properties of organic metal NHs—composites consisting of polyaniline particles that encapsulate a large number of metal nanoparticles—to rapidly and simultaneously identify food poisoning-inducing bacteria called enterohemorrhagic Escherichia coli (E. coli O26 and E. coli O157) and Staphylococcus aureus.
Chemical reactions often produce messy mixtures of different products. Hence, chemists spend a lot of time coaxing their reactions to be more selective to make particular target molecules. Now, an international team of researchers has achieved that kind of selectivity by delivering voltage pulses to a single molecule through an incredibly sharp tip.
“Controlling the pathway of a chemical reaction, depending on the voltage pulses used, is unprecedented and very alluring to chemists,” says KAUST’s Shadi Fatayer.
The team used an instrument that combines scanning tunneling microscopy (STM) and atomic force microscopy (AFM). Both techniques can map out the positions of atoms within individual molecules using a tip that may be just a few atoms wide. But the voltage can also be used to break bonds within a molecule, potentially allowing new bonds to form.
Researchers looking to synthesize a brighter and more stable nanoparticle for optical applications found that their creation instead exhibited a more surprising property: bursts of superfluorescence that occurred at both room temperature and regular intervals. The work could lead to the development of faster microchips, neurosensors, or materials for use in quantum computing applications, as well as a number of biological studies.
Superfluorescence occurs when atoms within a material synchronize and simultaneously emit a short but intense burst of light. The property is valuable for quantum optical applications, but extremely difficult to achieve at room temperatures and for intervals long enough to be useful.
The material in question—lanthanide-doped upconversion nanoparticle, or UCNP—was synthesized by the research team in an effort to create a “brighter” optical material. They produced hexagonal ceramic crystals ranging from 50 nanometers (nm) to 500 nm in size and began testing their lasing properties, which resulted in several impressive breakthroughs.
A team of researchers at the University of Vienna, the Austrian Academy of Sciences and the University of Duisburg-Essen have found a new mechanism that fundamentally alters the interaction between optically levitated nanoparticles. Their experiment demonstrates previously unattainable levels of control over the coupling in arrays of particles, thereby creating a new platform to study complex physical phenomena. The results are published in this week’s issue of Science.
Imagine dust particles randomly floating around in the room. When a laser is switched on, the particles will experience forces of light and once a particle comes too close it will be trapped in the focus of the beam. This is the basis of Arthur Ashkin’s pioneering Nobel prize work of optical tweezers. When two or more particles are in the vicinity, light can be reflected back and forth between them to form standing waves of light, in which the particles self-align like a crystal of particles bound by light. This phenomenon, also called optical binding, has been known and studied for more than 30 years.
It came as quite a surprise to the researchers in Vienna when they saw a completely different behavior than was expected when studying forces between two glass nanoparticles. Not only could they change the strength and the sign of the binding force, but they could even see one particle, say the left, acting on the other, the right, without the right acting back on the left. What seems like a violation of Newton’s third law (everything that is being acted upon acts back with same strength but opposite sign) is so-called non-reciprocal behavior and occurs in situations in which a system can lose energy to its environment, in this case the laser. Something was obviously missing from our current theory of optical binding.
The team even transmitted video games through the atoms to a monitor.
Scientists at the US National Institute of Standards have developed an ‘Atomic Television’ that uses lasers and atom clouds to pick up video transmissions that meet the 480i resolution standard. The team demonstrated the same by transmitting live video feeds and even video games through the atoms to a monitor.
This will be very useful in progressing the field of quantum computers and communication.
Researchers at the Max Planck Institute of Quantum Optics set a new record after achieving a quantum entanglement of 14 photons, the largest on record so far, an institutional press release said.
Quantum entanglement, famously described by Albery Einstein as “spooky action at a distance” is a phenomenon where particles become intertwined in such a way that they cease to exist individually, and changing the specific property of one results in an instant change of its partner, even if it is far away.
Max Planck of Quantum Optics.
Quantum entanglement, famously described by Albery Einstein as “spooky action at a distance” is a phenomenon where particles become intertwined in such a way that they cease to exist individually, and changing the specific property of one results in an instant change of its partner, even if it is far away.
Cutting intricate patterns as small as several billionths of a meter deep and wide, the focused ion beam (FIB) is an essential tool for deconstructing and imaging tiny industrial parts to ensure they were fabricated correctly. When a beam of ions, typically of the heavy metal gallium, bombards the material to be machined, the ions eject atoms from the surface—a process known as milling—to sculpt the workpiece.
Beyond its traditional uses in the semiconductor industry, the FIB has also become a critical tool for fabricating prototypes of complex three-dimensional devices, ranging from lenses that focus light to conduits that channel fluid. Researchers also use the FIB to dissect biological and material samples to image their internal structure.
However, the FIB process has been limited by a trade-off between high speed and fine resolution. On the one hand, increasing the ion current allows a FIB to cut into the workpiece deeper and faster. On the other hand, the increased current carries a larger number of positively charged ions, which electrically repel each other and defocus the beam. A larger, diffuse beam, which can be about 100 nanometers in diameter or 10 times wider than a typical narrow beam, not only limits the ability to fabricate fine patterns but can also damage the workpiece at the perimeter of the milled region. As a result, the FIB has not been the process of choice for those trying to machine many tiny parts in a hurry.
