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Researchers in the US, Poland and Korea have observed photon avalanching – a chain-reaction-like process in which the absorption of a single photon triggers the emission of many – in tiny crystals just 25–30 nm in diameter. This highly nonlinear phenomenon had previously only been seen in bulk materials, and team leader James Schuck says that replicating it in nanoparticles could lead to “revolutionary new applications” in imaging, sensing and light detection (Nature 589 230).

Photon avalanching involves a process known as upconversion, whereby the energy of the emitted photons is higher than the energy of the photons that triggered the avalanche. Materials based on lanthanides (chemical elements with atomic numbers between 57 and 71) can support this process in part because their internal atomic structure enables them to store energy for long periods of time. Even so, achieving photon avalanching in lanthanide systems is difficult because high concentrations of lanthanide ions are needed to keep the avalanche going, and the relatively large volume of material required has previously restricted applications.

In the latest work, Schuck and colleagues at Columbia University, together with collaborators at Lawrence Berkeley National Laboratory, the Polish Academy of Sciences and Sungkyunkwan University, observed photon avalanching in lanthanide nanocrystals after exciting them with a laser at near-infrared wavelengths of either 1,064 or 1450 nm. The crystals are based on sodium yttrium fluoride in which 8% of the yttrium ions have been replaced with thulium. This doping fraction is much higher than the 0.2–1% typically found in previous work on photon avalanching.

When water vapour spontaneously condenses inside capillaries just 1 nm thick, it behaves according to the 150-year-old Kelvin equation – defying predictions that the theory breaks down at the atomic scale. Indeed, researchers at the University of Manchester have showed that the equation is valid even for capillaries that accommodate only a single layer of water molecules (Nature 588 250).

Condensation inside capillaries is ubiquitous and many physical processes – including friction, stiction, lubrication and corrosion – are affected by it. The Kelvin equation relates the surface tension of water to its temperature and the diameter of its meniscus. It predicts that if the ambient humidity is between 30–50%, then flat capillaries less than 1.5 nm thick will spontaneously fill with water that condenses from the air.

Real world capillaries can be even smaller, but for them it is impossible to define the curvature of a liquid’s meniscus so the Kelvin equation should no longer hold. However, because such tight confinement is difficult to achieve in the laboratory, this had yet to be tested.

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Professor Pattie Maes deep insights working with her research team of Joanne Leong, Pat Pataranutaporn, Valdemar Danry are world leading in their translational research on tech-human interaction. Their highly interdisciplinary work covering decades of MIT Lab pioneering inventions integrates human computer interaction (HCI), sensor technologies, AI / machine learning, nano-tech, brain computer interfaces, design and HCI, psychology, neuroscience and much more. I participated in their day-long workshop and followed-up with more than three hours of interviews of which over an hour is transcribed in this article. All insights in this article stem from my daily pro bono work with (now) more than 400,000 CEOs, investors, scientists/experts. MIT Media Lab Fluid Interfaces research team work is particularly key with the June 21 announcement of the Metaverse Standards Forum, a open standards group, with big tech supporting such as Microsoft and Meta, chaired by Neil Trevett, Khronos President and VP Developer Ecosystems at NVIDIA. I have a follow-up interview with Neil and Forbes article in the works. In addition, these recent announcements also highlight why Pattie Maes work is so important: Deep Mind’s Gato multi-modal, multi-task, single generalist agent foundational to artificial general intelligence (AGI); Google’s LaMDA Language Model for Dialogue Applications which can engage in free-flowing dialogue; Microsoft’s Build Conference announcements on Azure AI and OpenAI practical tools / solutions and responsible AI; OpenAI’s DALL-E 2 producing realistic images and art from natural language descriptions.

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As they grow, solid tumors surround themselves with a thick, hard-to-penetrate wall of molecular defenses. Getting drugs past that barricade is notoriously difficult. Now, scientists at UT Southwestern have developed nanoparticles that can break down the physical barriers around tumors to reach cancer cells. Once inside, the nanoparticles release their payload: a gene editing system that alters DNA inside the tumor, blocking its growth and activating the immune system.

The new nanoparticles, described in Nature Nanotechnology, effectively stopped the growth and spread of ovarian and liver tumors in mice. The system offers a new path forward for the use of the gene editing tool known as CRISPR-Cas9 in cancer treatment, said study leader Daniel Siegwart, Ph.D., Associate Professor of Biochemistry at UT Southwestern.

“Although CRISPR offers a new approach for treating cancer, the technology has been severely hindered by the low efficiency of delivering payloads into tumors,” said Dr. Siegwart, a member of the Harold C. Simmons Comprehensive Cancer Center.

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For a few years now, spent grain, the cereal residue from breweries, has been reused in animal feed. This material could also be used in nanotechnology. Professor Federico Rosei’s team at the Institut national de la recherche scientifique (INRS) has shown that microbrewery waste can be used as a carbon source to synthesize quantum dots. The work, done in collaboration with Claudiane Ouellet-Plamondon of the École de technologie supérieure (ÉTS), was published in the Royal Society of Chemistry’s journal RSC Advances.

Often considered “artificial atoms,” quantum dots are used in the transmission of light. With a range of interesting physicochemical properties, this type of nanotechnology has been successfully used as a sensor in biomedicine or as LEDs in next generation displays. But there is a drawback. Current quantum dots are produced with heavy and toxic metals like cadmium. Carbon is an interesting alternative, both for its biocompatibility and its accessibility.

A group of scientists working on surface-enhanced Raman spectroscopy (SERS) has made a nanoruler to provide insight into the longitudinal plasmonic fields in nanocavities, according to research published in the Journal of the American Chemical Society.

SERS is a highly sensitive and powerful spectral analysis technique applicable in various fields. In contrast to weak Raman scattering, SERS achieves a dramatically enhanced Raman signal of up to 10^10–15, allowing the analysis of single molecules.

“How we develop the technology depends, to a large extent, on what we know about plasmonic fields. In the experiments, we observed an uneven distribution in the plasmonic field at the nano-scale. But it lacks theoretic and experimental support. So we decided to figure it out,” said Yang Liangbao, who leads the team at the Hefei Institutes of Physical Science of the Chinese Academy of Sciences.

Quantum computers are one of the key future technologies of the 21^st century. Researchers at Paderborn University, working under Professor Thomas Zentgraf and in cooperation with colleagues from the Australian National University and Singapore University of Technology and Design, have developed a new technology for manipulating light that can be used as a basis for future optical quantum computers. The results have now been published in Nature Photonics.

New optical elements for manipulating light will allow for more advanced applications in modern information technology, particularly in quantum computers. However, a major challenge that remains is non-reciprocal light propagation through nanostructured surfaces, where these surfaces have been manipulated at a tiny scale.

Professor Thomas Zentgraf, head of the working group for ultrafast nanophotonics at Paderborn University, explains that “in reciprocal propagation, light can take the same path forward and backward through a structure; however, non-reciprocal propagation is comparable to a one-way street where it can only spread out in one direction.”

An international team of researchers has demonstrated a technique that allows them to align gold nanorods using magnetic fields, while preserving the underlying optical properties of the gold nanorods.

“Gold nanorods are of interest because they can absorb and scatter specific wavelengths of light, making them attractive for use in applications such as biomedical imaging, sensors, and other technologies,” says Joe Tracy, corresponding author of a paper on the work and a professor of materials science and engineering at North Carolina State University.

It is possible to tune the wavelengths of light absorbed and scattered by engineering the dimensions of the gold nanorods. Magnetically controlling their orientation makes it possible to further control and modulate which wavelengths the nanorods respond to.