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Category: nanotechnology – Page 83

Researchers in China have produced a phenomenon known as the giant skyrmion topological Hall effect in a two-dimensional material using only a small amount of current to manipulate the skyrmions responsible for it. The finding, which a team at Huazhong University of Science and Technology in Hubei observed in a ferromagnetic crystal discovered in 2022, comes about thanks to an electronic spin interaction known to stabilize skyrmions. Since the effect was apparent at a wide range of temperatures, including room temperature, it could prove useful for developing two-dimensional topological and spintronic devices such as racetrack memory, logic gates and spin nano-oscillators.

Skyrmions are quasiparticles with a vortex-like structure, and they exist in many materials, notably magnetic thin films and multilayers. They are robust to external perturbations, and at just tens of nanometres across, they are much smaller than the magnetic domains used to encode data in today’s hard disks. That makes them ideal building blocks for future data storage technologies such as “racetrack” memories.

Skyrmions can generally be identified in a material by spotting unusual features (for example, abnormal resistivity) in the Hall effect, which occurs when electrons flow through a conductor in the presence of an applied magnetic field. The magnetic field exerts a sideways force on the electrons, leading to a voltage difference in the conductor that is proportional to the strength of the field. If the conductor has an internal magnetic field or magnetic spin texture, like a skyrmion does, this also affects the electrons. In these circumstances, the Hall effect is known as the skyrmion topological Hall effect (THE).

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Johns Hopkins researchers have identified minuscule particles that supercharge therapeutic cancer vaccines, which train the immune system to attack tumors. These new lipid nanoparticles—tiny structures made of fat—not only stimulate a two-pronged immune system response that enhances the body’s ability to fight cancer but also make vaccines more effective in targeting tumors.

“This research marks a pivotal turning point in our understanding of how can be harnessed to optimize anticancer immunity,” said Hai-Quan Mao, director of Johns Hopkins’ Institute for NanoBioTechnology and professor in the Whiting School of Engineering’s Department of Materials Science and Engineering. “Our findings unlock new avenues for enhancing the efficacy of RNA-based treatments for and infectious diseases.”

The team’s results appear in Nature Biomedical Engineering.

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A nitrogen-vacancy (NV) center is a defect in the crystal structure of diamond, where a nitrogen atom replaces a carbon atom in the diamond lattice and a neighboring site in the lattice is vacant. This and other fluorescent defects in diamond, known as color centers, have attracted researchers’ attention owing to their quantum properties, such as single-photon emission at room temperature and with long coherence time. Their many applications include quantum information encoding and processing, and cell marking in biological studies.

Microfabrication in diamond is technically difficult, and nanodiamonds with color centers have been embedded in custom-designed structures as a way of integrating these quantum emitters into photonic devices. A study conducted at the University of São Paulo’s São Carlos Institute of Physics (IFSC-USP) in Brazil has established a method for this, as described in an article published in the journal Nanomaterials.

“We demonstrated a method of embedding fluorescent nanodiamonds in designed for this purpose, using two-photon polymerization [2PP],” Cleber Mendonça, a professor at IFSC-USP and last author of the article, told Agência FAPESP. “We studied the ideal concentration of nanodiamond in the photoresist to achieve structures with at least one fluorescent NV center and good structural and optical quality.” The photoresist is a light-sensitive material used in the fabrication process to transfer nanoscale patterns to the substrate.

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Detection efficiency is 1,000 times higher than conventional ion detectors due to high sensitivity.

An international research team led by quantum physicist Markus Arndt (University of Vienna) has achieved a breakthrough in the detection of protein ions: Due to their high energy sensitivity, superconducting nanowire detectors achieve almost 100% quantum efficiency and exceed the detection efficiency of conventional ion detectors at low energies by a factor of up to a 1,000. In contrast to conventional detectors, they can also distinguish macromolecules by their impact energy. This allows for more sensitive detection of proteins and it provides additional information in mass spectrometry. The results of this study were recently published in the journal Science Advances.

Advancements in Mass Spectrometry.

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A groundbreaking study introduces advanced nanometric optomechanical cavities, paving the way for more efficient quantum networks and improving quantum computing and communication technologies.

The ability to transmit information coherently in the band of the electromagnetic spectrum from microwave to infrared is vitally important to the development of the advanced quantum networks used in computing and communications.

A study conducted by researchers at the State University of Campinas (UNICAMP) in Brazil, in collaboration with colleagues at ETH Zurich in Switzerland and TU Delft in the Netherlands, focused on the use of nanometric optomechanical cavities for this purpose. These nanoscale resonators promote interaction between high-frequency mechanical vibrations and infrared light at wavelengths used by the telecommunications industry.

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By Chuck Brooks

Realizing the potential of Smart Cities will require public-private cooperation and security by design.

The idea of smart cities is starting to take shape as the digital era develops. A city that has developed a public-private infrastructure to support waste management, energy, transportation, water resources, smart building technology, sustainability, security operations and citizen services is referred to as a “smart city”. Realizing the potential of Smart Cities will require public-private cooperation and security by design.

A smart city functions as an applied innovation lab. Automation, robotics, enabling nanotechnologies, artificial intelligence (human/computer interface), printed electronics and photovoltaics, wearables (flexible electronics), and information technologies like real-time and predictive analytics, super-computing, 5G wireless networks, secure cloud computing, mobile devices, and virtualization are a few of the fascinating technological trends of the digital era that are influencing the development of smart cities.

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Moore’s Law predicts that computers get faster every two years because of the evolution of semiconductor chips.

Researchers at Tohoku University and the University of California, Santa Barbara, have shown a proof-of-concept of energy-efficient computer compatible with current AI. It utilizes a stochastic behavior of nanoscale spintronics devices and is particularly suitable for probabilistic computation problems such as inference and sampling.

The team presented the results at the IEEE International Electron Devices Meeting (IEDM 2023) on December 12, 2023.

With the slowing down of Moore’s Law, there has been an increasing demand for domain-specific hardware. A probabilistic computer with naturally stochastic building blocks (probabilistic bits, or p-bits) is a representative example due to its potential capability to efficiently address various computationally hard tasks in machine learning (ML) and artificial intelligence (AI).

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Self-propelled nanoparticles could potentially advance drug delivery and lab-on-a-chip systems — but they are prone to go rogue with random, directionless movements. Now, an international team of researchers has developed an approach to rein in the synthetic particles.

Led by Igor Aronson, the Dorothy Foehr Huck and J. Lloyd Huck Chair Professor of Biomedical Engineering, Chemistry and Mathematics at Penn State, the team redesigned the nanoparticles into a propeller shape to better control their movements and increase their functionality. They published their results in the journal Small (“Multifunctional Chiral Chemically-Powered Micropropellers for Cargo Transport and Manipulation”).

A propeller-shaped nanoparticle spins counterclockwise, triggered by a chemical reaction with hydrogen peroxide, followed by an upward movement, triggered by a magnetic field. The optimized shape of these particles allows researchers to better control the nanoparticles’ movements and to pick up and move cargo particles. (Video: Active Biomaterials Lab)

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A team of chemists, microbiologists and physicists at the University of Cambridge in the U.K. has developed a way to use solid-state nanopores and multiplexed DNA barcoding to identify misfolded proteins such as those involved in neurodegenerative disorders in blood samples. In their study, reported in the Journal of the American Chemical Society, the group used multiplexed DNA barcoding techniques to overcome problems with nanopore filtering techniques for isolating harmful oligomers.

Prior research has shown that the presence of harmful oligomers in the brain can lead to misfolding of proteins associated with neurodegenerative diseases such as Parkinson’s and Alzheimer’s disease. Medical researchers have been looking for a way to detect them in the blood as a way to diagnose neurodegenerative disease and to track the progression once it has been confirmed.

Unfortunately, finding them in complex mixtures such as blood has proven to be a daunting task. One approach has shown promise—using sensors—but to date, they cannot track target oligomers as they speed through customizable solid-state nanopore sensors. In this new effort, the research team overcame this problem by using customizable DNA nanostructures.

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There’s an unfortunate irony in cell therapy that holds it back from its full potential: Regenerating tissues often must be damaged to know if the treatment is working, such as surgically removing tissue to see if rejuvenation is occurring beneath.

The alternative isn’t much better: Patients can choose to wait and see if their health improves, but after weeks of uncertainty, they might find that no healing has taken place without a clear explanation as to why.

Jinhwan Kim, a new assistant professor of biomedical engineering at the University of California, Davis, who holds a joint appointment with the Department of Surgery at UC Davis Health, wants to change all of that. In his research program, he combines nanotechnology and novel bioimaging techniques to provide non-invasive, real-time monitoring of cellular function and health.

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