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Category: nanotechnology – Page 15

Porphyrin-based nanosheets capture viruses; researchers work to improve air flow for mask applications

The COVID-19 pandemic increased public awareness of the importance of mask use for personal protection. However, when the mesh size of mask fabrics is small enough to capture viruses, which are usually around one hundred nanometers in size, the fabric typically also restricts air flow, resulting in user discomfort. Researchers from Japan have now developed a new filter material that effectively captures nanoparticles, although further improvements are needed to make it suitable for comfortable mask use.

In a study published this month in Materials Advances, researchers from the Institute of Industrial Science at the University of Tokyo have developed a filter capable of capturing nanoparticles such as viruses. While the filter demonstrates high filtration efficiency, its airflow resistance is currently higher than the standards required for face masks, indicating that additional development is necessary before it can be used for personal protective equipment.

The filter is constructed from nanosheets consisting of an ordered mesh composed of porphyrins, which are flat, ring-shaped molecules with a central hole. The in the porphyrin molecules are suitably sized to allow the easy passage of the small gas molecules in air while blocking the movement of larger particles, such as viruses. The nanosheets are then supported on a fabric modified with nanofibers containing pores of several hundred nanometers to form the filter.

Closing the gaps—MXene-coated air filters show enhanced performance and reusability

Despite improvements to air filtration technology in the aftermath of the COVID-19 pandemic, some of the smallest particles—those of automobile and factory emissions—can still make their way through less efficient, but common filters. An interdisciplinary team of researchers from Drexel University’s College of Engineering have introduced a new way to improve textile-based filters by coating them with a type of two-dimensional nanomaterial called MXene.

Recently published in the journal C—Journal of Carbon Research, the team’s research reports that a non-woven polyester textile—a low-cost material with low filtration efficiency—coated with a thin layer of MXene nanomaterial can turn it into a potent filter capable of pulling some of the finest nanoparticles from the air.

“It can be challenging for common filters to contend with particles less than 100 nanometers, which include those emitted by industrial processes and automobiles,” said Michael Waring, Ph.D., a professor in Drexel’s College of Engineering, and co-author of the research. “Being able to augment a filter, through a simple coating process, to make it effective against these emissions is a significant development.”

Near-infrared spatiotemporal color vision in humans enabled by upconversion contact lenses

Based on the principle of refractive index matching, highly transparent upconversion contact lenses (UCLs) with a high concentration of upconversion nanoparticles (UCNPs) were developed. These lenses efficiently convert multispectral near-infrared (NIR) light into the three primary visible colors, enabling humans to acquire wearable NIR color vision.

Revolutionary Contact Lenses Let Human Eyes See Invisible Light

Scientists in China have developed contact lenses that let wearers see light normally invisible to the human eye. Cooler still, the lenses work better through closed eyelids, and other versions could help correct color blindness.

The human eye can see a relatively limited range of colors – light with wavelengths of between about 400 and 700 nanometers. In typical human-centric fashion, we call that the ‘visible’ part of the spectrum, even though other animals can see beyond it.

In a new study, scientists have helped humans catch a glimpse of light between 800 and 1,600 nanometers in length, a range we normally can’t see known as infrared. The trick is to pop in a pair of contact lenses embedded with nanoparticles that convert the infrared wavelengths into visible ones.

Infrared contact lenses allow people to see in the dark, even with their eyes closed

Neuroscientists and materials scientists have created contact lenses that enable infrared vision in both humans and mice by converting infrared light into visible light. Unlike infrared night vision goggles, the contact lenses, described in the journal Cell, do not require a power source—and they enable the wearer to perceive multiple infrared wavelengths. Because they’re transparent, users can see both infrared and visible light simultaneously, though infrared vision was enhanced when participants had their eyes closed.

“Our research opens up the potential for noninvasive wearable devices to give people super-vision,” says senior author Tian Xue, a neuroscientist at the University of Science and Technology of China. “There are many potential applications right away for this material. For example, flickering infrared light could be used to transmit information in security, rescue, encryption or anti-counterfeiting settings.”

The contact lens technology uses nanoparticles that absorb infrared light and convert it into wavelengths that are visible to mammalian eyes (e.g., in the 400–700 nm range). The nanoparticles specifically enable the detection of “near-infrared light,” which is infrared light in the 800‑1600 nm range, just beyond what humans can already see.

An accidentally discovered class of nanostructured materials can passively harvest water from air

A serendipitous observation in a Chemical Engineering lab at Penn Engineering has led to a surprising discovery: a new class of nanostructured materials that can pull water from the air, collect it in pores and release it onto surfaces without the need for any external energy.

The research, published in Science Advances, describes a material that could open the door to new ways to collect water from the air in arid regions and devices that cool electronics or buildings using the power of evaporation.

The interdisciplinary team includes Daeyeon Lee, Russell Pearce and Elizabeth Crimian Heuer Professor in Chemical and Biomolecular Engineering (CBE); Amish Patel, Professor in CBE; Baekmin Kim, a postdoctoral scholar in Lee’s lab and first author; and Stefan Guldin, Professor in Complex Soft Matter at the Technical University of Munich.

Mind the band gap: Researchers create nanoscale forms of elementary semiconductor with tunable electronic properties

Professor Andrei Khlobystov, School of Chemistry, University of Nottingham, said, “We have investigated the ultimate limit for nanowire size while preserving useful . This is possible for selenium because the phenomenon of quantum confinement can be effectively balanced by distortions in the atomic structure, thus allowing the band gap to remain within a useful range.”

The researchers hope that these new materials will be incorporated into electronic devices in the future. Accurately tuning the band gap of by changing the diameter of the nanowire could lead to the design of a variety of customized electronic devices using only a single element.

Nano-engineered thermoelectrics enable scalable, compressor-free cooling

Researchers at the Johns Hopkins Applied Physics Laboratory (APL) in Laurel, Maryland, have developed a new, easily manufacturable solid-state thermoelectric refrigeration technology with nano-engineered materials that is twice as efficient as devices made with commercially available bulk thermoelectric materials.

As global demand grows for more energy-efficient, reliable and compact cooling solutions, this advancement offers a scalable alternative to traditional compressor-based refrigeration.

In a paper published in Nature Communications, a team of researchers from APL and refrigeration engineers from Samsung Electronics demonstrated improved heat-pumping efficiency and capacity in refrigeration systems attributable to high-performance nano-engineered thermoelectric materials invented at APL known as controlled hierarchically engineered superlattice structures (CHESS).

«Matrix: Start» — researchers powered 350 LEDs from the human body

Researchers at the University of Alabama in the United States have used duct tape from a store to create a triboelectric nanogenerator capable of collect electricity from the human body and the environment.

Their development is capable of powering small devices such as biosensors by converting mechanical energy from friction and movement into electricity. The generator is made of metallized films polyethylene terephthalate, which act as electrodes, and layers of adhesive tape.

The developers emphasize that power generation occurs through interaction polypropylene and of the acrylic adhesive layer when they are pressed and released. At the same time, due to the weak intermolecular interaction (Van der Waals forces) on the borders of the atomic-sized gaps.

UNM Scientists Discover How Nanoparticles of Toxic Metal Used in MRI Scans Infiltrate Human Tissue

University of New Mexico researchers studying the health risks posed by gadolinium, a toxic rare earth metal used in MRI scans, have found that oxalic acid, a molecule found in many foods, can generate nanoparticles of the metal in human tissues.

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