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In materials science, achromatic optical components can be designed with high transparency and low dispersion. Materials scientists have shown that although metals are highly opaque, densely packed arrays of metallic nanoparticles with more than 75 percent metal by volume can become more transparent to infrared radiation than dielectrics such as germanium. Such arrays can form effective dielectrics that are virtually dispersion-free across ultra-broadband ranges of wavelengths to engineer a variety of next-generation metamaterial-based optical devices.

Scientists can tune the local refractive indices of such materials by altering the size, shape and spacing of nanoparticles to design gradient-index lenses that guide and focus light on the microscale. The electric field can be strongly concentrated in the gaps between metallic nanoparticles for the simultaneous focusing and ‘squeezing’ of the dielectric field to produce strong, doubly enhanced hotspots. Scientists can use these hotspots to boost measurements made using infrared spectroscopy and other non-linear processes across a broad frequency range.

In a recent study now published in Nature Communications, Samuel J. Palmer and an interdisciplinary research team in the departments of Physics, Mathematics and Nanotechnology in the U.K., Spain and Germany, showed that artificial dielectrics can remain highly transparent to infrared radiation and observed this outcome even when the particles were nanoscopic. They demonstrated the electric field penetrates the particles (rendering them imperfect for conduction) for strong interactions to occur between them in a tightly packed arrangement. The results will allow materials scientists to design optical components that are achromatic for applications in the mid-to-infrared wavelength region.

Continue reading “Extraordinarily transparent compact metallic metamaterials” »

MIT professor Sangeeta Bhatia is currently devising a simple urine test that works just like a pregnancy test to detect cancer the moment it starts. In this video, Big Think contributor Susan Hockfield, president emerita of MIT, explains how the new technology works.

Center Stage in the current issue of ACS Central Science: A Conversation with Prof. Jackie Ying, founding director of the A*STAR Institute NanoBio lab in Singapore. Using #nanomaterials to develop inexpensive medical technologies:

Charging almost instantly and offering massive power density, Nawa’s innovative ultracapacitors are ready to make a mark across industries from automotive to power tools and aviation. And after raising more than US$10 million, this French company is going into mass production.

University of Sydney research provides new evidence that nanoparticles, which are present in many food items, may have a substantial and harmful influence on human health.

The study investigated the health impacts of food additive E171 (titanium dioxide nanoparticles) which is commonly used in high quantities in foods and some medicines as a whitening agent. Found in more than 900 food products such as chewing gum and mayonnaise, E171 is consumed in high proportion everyday by the general population.

Published in Frontiers in Nutrition, the mice study found that consumption of food containing E171 has an impact on the gut microbiota (defined by the trillions of bacteria that inhabit the gut) which could trigger diseases such as inflammatory bowel diseases and colorectal cancer.

Continue reading “Common food additive E171 found to affect gut microbiota” »

University of Sydney research provides new evidence that nanoparticles, which are present in many food items, may have a substantial and harmful influence on human health.

The study investigated the health impacts of food additive E171 (titanium dioxide nanoparticles) which is commonly used in high quantities in foods and some medicines as a whitening agent. Found in more than 900 food products such as chewing gum and mayonnaise, E171 is consumed in high proportion everyday by the general population.

Published in Frontiers in Nutrition, the mice study found that consumption of food containing E171 has an impact on the gut microbiota (defined by the trillions of bacteria that inhabit the gut) which could trigger diseases such as inflammatory bowel diseases and colorectal cancer.

Continue reading “Common food additive found to affect gut microbiota” »

Nanostructures can be designed such a way that the quantum confinement allows only certain electron energy levels. Researchers from IMDEA Nanociencia, UAM and ICMM-CSIC have, for the first time, observed a discrete pattern of electron energies in an unconfined system, which could lead to new ways of modifying the surface properties of materials.

A research group from IMDEA Nanoscience and Universidad Autónoma de Madrid has found for the first time experimental evidence that one-dimensional lattices with nanoscale periodicity can interact with the electrons from a bidimensional gas by spatially separating their different wavelengths by means of a physical phenomenon known as Bragg diffraction. This phenomenon is well-known for wave propagation in general and is responsible for the iridescent color observed upon illumination of a CD surface. Due to the wave-particle duality proposed by De Broglie in 1924, electrons also present a wave-like behavior and, thus, diffraction phenomena. Actually, the observation that low-energy free electrons undergo diffraction processes upon interaction with well-ordered atomic lattices on solid surfaces was the first experimental confirmation of the wave-particle duality.

Gazibegović, Ph.D. candidate in the group of prof. Erik Bakkers at the department of Applied Physics, developed a device made of ultrathin networks of nanowires in the shape of “hashtags.” This device allows pairs of Majorana particles to exchange position and keep track of the changes occurred, in a phenomenon known as “braiding.” This event is considered as a striking proof of the existence of Majorana particles, and it represents a crucial step towards their use as building blocks for the development of quantum computers. With two Nature publications in her pocket, Gazibegović is ready to defend her Ph.D. thesis on May 10.

In 1937, the Italian theoretical physicist Ettore Majorana hypothesized the existence of a unique particle that is its own antiparticle. This particle, also referred to as a “Majorana fermion,” can also exist as a “quasiparticle,” a collective phenomenon that behaves like an individual particle, as in waves forming on the water. The water itself stays in the same place, but the wave can “travel” on the surface, as if it were a single particle in movement. For many years, physicists have been trying to find the Majorana particle without success. Yet, in the last decade, scientists from Eindhoven University of Technology have taken great leap forwards in proving the existence of Majorana particles, also thanks to the research of Gazibegović and her collaborations with the University of Delft, Philips Research and the University of California – Santa Barbara.

Continue reading “28 years old and closer than ever to the solving of the mistery of the Majorana particles” »

Researchers at Johannes Gutenberg University Mainz (JGU) have succeeded in developing a key constituent of a novel unconventional computing concept. This constituent employs the same magnetic structures that are being researched in connection with storing electronic data on shift registers known as racetracks. In this, researchers investigate so-called skyrmions, which are magnetic vortex-like structures, as potential bit units for data storage. However, the recently announced new approach has a particular relevance to probabilistic computing. This is an alternative concept for electronic data processing where information is transferred in the form of probabilities rather than in the conventional binary form of 1 and 0. The number 2/3, for instance, could be expressed as a long sequence of 1 and 0 digits, with 2/3 being ones and 1/3 being zeros. The key element lacking in this approach was a functioning bit reshuffler, i.e., a device that randomly rearranges a sequence of digits without changing the total number of 1s and 0s in the sequence. That is exactly what the skyrmions are intended to achieve. The results of this research have been published in the journal Nature Nanotechnology.

The researchers used thin magnetic metallic films for their investigations. These were examined in Mainz under a special microscope that made the magnetic alignments in the metallic films visible. The films have the special characteristic of being magnetized in vertical alignment to the film plane, which makes stabilization of the magnetic skyrmions possible in the first place. Skyrmions can basically be imagined as small magnetic vortices, similar to hair whorls. These structures exhibit a so-called topological stabilization that protects them from collapsing too easily – as a hair whorl resists being easily straightened. It is precisely this characteristic that makes skyrmions very promising when it comes to use in technical applications such as, in this particular case, information storage. The advantage is that the increased stability reduces the probability of unintentional data loss and ensures the overall quantity of bits is maintained.