Researchers explore using light to levitate discs in the mesosphere

Phys.org  February 15, 2021 To improve weather prediction sensors need to be sent to mesosphere. The satellites and rockets currently used have problems as the air is too thick and friction and heat would make long-duration flights impractical. Researchers at the University of Pennsylvania constructed and demonstrated light-driven levitation of macroscopic polymer films with nanostructured surface as candidates for long-duration near-space flight. The disks were made of 0.5-micron-thick mylar film coated with carbon nanotubes on one side. When illuminated with light intensity comparable to natural sunlight, the polymer disk heats up and interacts with incident gas molecules differently on the […]

Rapid Identification of Ricin in Serum Samples Using LC–MS/MS

Global Biodefense  January 23, 2021 Researchers in Israel have developed a sensitive, rapid, antibody-independent assay for the identification of ricin in body fluids using mass spectrometry. The assay involves lectin affinity capturing of ricin by easy-to-use commercial lactose–agarose beads, followed by tryptic digestion and selected marker identification using targeted Multiple Reaction Monitoring analysis. This enables ricin identification down to 5 ng/mL in serum samples in 2.5 hours. They demonstrated the technology in a clinical scenario where the toxin was identified in an abdominal fluid sample taken 72 h post self-injection of castor beans extraction. This method has the potential application […]

Researchers report quantum-limit-approaching chemical sensing chip

Phys.org  January 11, 2021 To fabricate high‐density random metallic nanopatterns with accurately controlled nanogaps an international team of researchers (USA – SUNY Buffalo, China, Saudi Arabia) used four molecules (BZT, 4-MBA, BPT, and TPT), each with different lengths. They used atomic layer deposition and self-assembled monolayers instead of electron-beam lithography. The resulting SERS (surface-enhanced Raman spectroscopy) chip with unprecedented uniformity is relatively inexpensive to produce and has gap size approaching the quantum regime of ≈0.78 nm. They demonstrated its potential for quantitative sensing with the relative standard deviation of 4.3% over large area. All chemicals have unique light-scattering signatures; therefore, […]

Trapping light without back reflections

Phys.org  January 4, 2021 Due to material imperfections, some amount of light is reflected backwards in microresonators which disturbs their function. To reduce the unwanted backscattering an international team of researchers (UK, Germany) used the principle of noise cancelling headphone and introduced out-of-phase light to cancel out optical interference. To generate the out-of-phase light, the researchers position a sharp metal tip close to the microresonator surface. The tip also causes light to scatter backwards. As the phase of the reflected light can be chosen by controlling the position of the tip, backscattered light’s phase can be set so it annihilates […]

Wireless, ultra-thin and battery-free strain sensors that are 10 times more sensitive

EurekAlert  December 15, 2020 Performance of conventional strain sensors has always been limited by the nature of sensing materials used, and users have limited options of customizing the sensors for specific applications. Researchers in Singapore have developed flexible, stretchable, and electrically conductive nanomaterials called MXenes and fabricated strain sensors which are ultra-thin, battery-free and transmit data wirelessly. The sensors are 10 times more sensitive when measuring minute movements of industrial robotic arms, compared to existing technology. In precision manufacturing it helps improve the overall safety of robotic arms by providing automated feedback on precise movements with an error margin below […]

Breakthrough optical sensor mimics human eye, a key step toward better AI

Science Daily  December 8, 2020 Neuromorphic processors are still designed for traditional computer architectures. Researchers at the State University of Oregon have shown that a simple photosensitive capacitor will inherently reproduce certain aspects of biological retinas. They found that capacitors based on metal halide perovskites will output a brief voltage spike in response to changes in incident light intensity but output zero voltage under constant illumination. The new sensor could be a perfect match for the neuromorphic computers that will power the next generation of artificial intelligence in applications like self-driving cars, robotics, and advanced image recognition…read more. Open Access […]

Smellicopter: An obstacle-avoiding drone that uses a live moth antenna to seek out smells

Science Daily  December 8, 2020 A team of researchers in the US (University of Washington, University Maryland) used antennae from the Manduca sexta hawkmoth for Smellicopter. One scent molecule in a moth antenna can trigger lots of cellular responses amplifying chemical signals. This process is super-efficient, specific, and fast. Researchers placed moths in the fridge to anesthetize them before removing an antenna. Once separated from the live moth, the antenna stays biologically and chemically active for up to four hours which can be extended by storing antennae in the fridge. In tests the moth antenna reacted more quickly and took […]

Quantum nanodiamonds may help detect disease earlier

Science Daily  November 25, 2020 Researchers in the UK investigated fluorescent nanodiamonds as an ultrasensitive label for in vitro diagnostics, using a microwave field to modulate emission intensity and frequency-domain analysis to separate the signal from background autofluorescence, which typically limits sensitivity. Focusing on the widely used, low-cost lateral flow format as an exemplar, they achieved a detection limit of 8.2 × 10−19 molar for a biotin–avidin model, 105 times more sensitive than that obtained using gold nanoparticles. Single-copy detection of HIV-1 RNA can be achieved with the addition of a 10-minute isothermal amplification step. This ultrasensitive quantum diagnostics platform […]

Analysis paves way for more sensitive quantum sensors

Nanowerk  November 16, 2020 Researchers at the University of Chicago proposed creating a string of photonic cavities, where photons can be transported to adjacent cavities. Such a string could be used as a quantum sensor. By harnessing non-Hermitian dynamics, where dissipation leads to interesting consequences, they were able to calculate that a string of these cavities would increase the sensitivity of the sensor much more than the number of cavities added. In fact, it would increase the sensitivity exponentially in system size. To prove the theory, they are building a network of superconducting circuits that can move photons between cavities. […]

DARPA’s plan for an airborne COVID detector

Defense Systems  November 11, 2020 The small and variable characteristics of the virus combined with complex indoor environments make using a single detection and measurement technique extraordinarily difficult. Optical environmental sensors, which can offer fast detection times, are not always able to discriminate between benign and pathogenic material. The SenSARS program (Pre-solicitation) aims to overcome these existing challenges to environmental monitoring. DARPA is primarily interested in three use cases: detecting the virus in a 50-cubic-meter office, similar detection in a 300-cubic-meter conference room or classroom, and central monitoring of HVAC systems in buildings up to 10 stories. Solutions must have […]