A New High-Pressure High-Temperature Phase of Silver Antimonate AgSbO with Strong Ag-O Hybridization.

We report on a new polymorph of silver antimonate AgSbO discovered with the use of high-pressure high-temperature synthesis at 16 GPa and 1380 °C. The crystal structure is determined from X-ray powder diffraction, and we find this new high-pressure phase crystallizes in monoclinic space group 2/ with the following values: = 8.4570(3) Å, = 9.

The effect of decoupling humidity control on aerosol drug delivery during HFNC for infants.

Background: Aerosol therapy is commonly used during treatment with high-flow nasal cannula (HFNC) in the intensive care unit (ICU). Heated humidification inside the HFNC tubing circuit leads to unwanted condensation, which may greatly limit the efficiency of drug delivery. In this study, we aimed to investigate whether a novel humidification system, which decouples temperature and humidity control, can improve the delivered dose.

Suppressing torsional buckling in auxetic meta-shells.

Take a thin cylindrical shell and twist it; it will buckle immediately. Such unavoidable torsional buckling can lead to systemic failure, for example by disrupting the blood flow through arteries. In this study, we prevent this torsional buckling instability using a combination of auxeticity and orthotropy in cylindrical metamaterial shells with a holey pattern.

Thermal Properties of Athermal Granular Materials.

Dry granular materials consist of a vast ensemble of discrete solid particles interacting through complex frictional forces at the contact points. The particles are so large that these systems are believed to be completely athermal. Here, we arrest the dynamics of a flowing granular material in a steady-state-flow configuration, enabling an isolated examination of aging at the particle contacts without granular rearrangements.

Electroless Ionization Mass Spectrometry Using a Compact Electrokinetic Ionization Source.

We introduce a new ionization technique for compact, portable mass spectrometers. It consists of a syringe with sample liquid capped by a self-ionizing spray nozzle containing a microfabricated nozzle chip. Interaction of the sample liquid with the nozzle wall results in electrical charging without the need for electronics.

Molecular Probing of the Microscopic Pressure at Contact Interfaces.

Obtaining insights into friction at the nanoscopic level and being able to translate these into macroscopic friction behavior in real-world systems is of paramount importance in many contexts, ranging from transportation to high-precision technology and seismology. Since friction is controlled by the local pressure at the contact it is important to be able to detect both the real contact area and the nanoscopic local pressure distribution simultaneously. In this paper, we present a method that uses planarizable molecular probes in combination with fluorescence microscopy to achieve this goal.

Perturbation-induced granular fluidization as a model for remote earthquake triggering.

Studying the effect of mechanical perturbations on granular systems is crucial for understanding soil stability, avalanches, and earthquakes. We investigate a granular system as a laboratory proxy for fault gouge. When subjected to a slow shear, granular materials typically exhibit a stress overshoot before reaching a steady state.

Elucidating the role of water in collagen self-assembly by isotopically modulating collagen hydration.

Water is known to play an important role in collagen self-assembly, but it is still largely unclear how water-collagen interactions influence the assembly process and determine the fibril network properties. Here, we use the H[Formula: see text]O/D[Formula: see text]O isotope effect on the hydrogen-bond strength in water to investigate the role of hydration in collagen self-assembly. We dissolve collagen in H[Formula: see text]O and D[Formula: see text]O and compare the growth kinetics and the structure of the collagen assemblies formed in these water isotopomers.

Resolving Multi-Asperity Contacts at the Nanoscale through Super-Resolution Fluorescence Imaging.

Contact mechanics, spanning nanometer to tectonic scales, faces long-standing challenges arising from multiscale random roughness, which hinders experimental validation of theories. Understanding multi-asperity rough contacts is vital for addressing catastrophic consequences of these contacts failing such as earthquakes and for diverse technological applications. To visualize such contacts, we introduce a super-resolution microscopy method utilizing spontaneous millisecond ON/OFF fluorescence blinking of contact-sensitive molecular rotor molecules immobilized on a glass coverslip.

Improved Olfactory Deposition of Theophylline Using a Nanotech Soft Mist Nozzle Chip.

Currently, nasal administration of active pharmaceutical ingredients is most commonly performed using swirl-nozzle-based pump devices or pressurized syringes. However, they lead to limited deposition in the more active regions of the nasal cavity, especially the olfactory region, which is crucial for nose-to-brain drug delivery. This research proposes to improve deposition in the olfactory region by replacing the swirl nozzle with a nanoengineered nozzle chip containing micrometer-sized holes, which generates smaller droplets of 10-50 μm travelling at a lower plume velocity.

Visualization of the Sol-Gel Transition in Porous Networks Using Fluorescent Viscosity-Sensitive Probes.

The sol-gel transition involves the transformation of a colloidal suspension into a system-spanning, interconnected gel. This process is widely used to reinforce mechanically weakened porous artifacts, such as sculptures but the impact of the restricted geometry (porous network) on the gelation dynamics of the solution remains unclear. Here, using fluorescent viscosity-sensitive molecular rotors, confocal microscopy, and model pores, we visualize the local viscosity changes at the microscale that accompany the sol-gel transition of a methyltriethoxysilane solution into a gel network.

Droplet Size Distribution in Emulsions.

The droplet size in emulsions is known to affect the rheological properties and plays a crucial role in many applications of emulsions. Despite its importance, the underlying mechanisms governing droplet size in emulsification remain poorly understood. We investigate the average drop size and size distribution upon emulsification with a high-shear mixer for model oil-in-water emulsions stabilized by a surfactant.

Controlling Macroscopic Friction through Interfacial Siloxane Bonding.

Controlling macroscopic friction is crucial for numerous natural and industrial applications, ranging from forecasting earthquakes to miniaturizing semiconductor devices, but predicting and manipulating friction phenomena remains a challenge due to the unknown relationship between nanoscale and macroscopic friction. Here, we show experimentally that dry friction at multiasperity Si-on-Si interfaces is dominated by the formation of interfacial siloxane (Si─O─Si) bonds, the density of which can be precisely regulated by exposing plasma-cleaned silicon surfaces to dry nitrogen. Our results show how the bond density can be used to quantitatively understand and control the macroscopic friction.

Capillary Forces Lead to Pendant Crystals at the Liquid-Air Interface of Evaporating Salt Solutions.

We investigated the nucleation and growth processes of individual NaCl crystals from an evaporating salt solution that is supersaturated. We find that crystals nucleate at the liquid/vapor interface, resulting in distinct "pendant" crystals, which reach millimeter dimensions. The substantial size of the crystals induces deformation of the interface.

Generation of Aerosols by Noninvasive Respiratory Support Modalities: A Systematic Review and Meta-Analysis.

Importance: Infection control guidelines have historically classified high-flow nasal oxygen and noninvasive ventilation as aerosol-generating procedures that require specialized infection prevention and control measures.

Objective: To evaluate the current evidence that high-flow nasal oxygen and noninvasive ventilation are associated with pathogen-laden aerosols and aerosol generation.

Data Sources: A systematic search of EMBASE and PubMed/MEDLINE up to March 15, 2023, and CINAHL and ClinicalTrials.

Super-resolution Fluorescence Imaging of Recycled Polymer Blends via Hydrogen Bond-Assisted Adsorption of a Nile Red Derivative.

A key challenge in the recycling of multilayer plastic films of polyethylene and polyamide, as typically used for food packaging, is to assess and control the phase separation of the two types of polymers in the recycled material, the specifics of which determine the mechanical strength of the recycled material. However, visualizing the polyamide-in-polyethylene domains with conventional fluorescence methods or electron microscopy is challenging. We present a new approach that combines the point accumulation in nanoscale topography (PAINT) super-resolution method with a newly synthesized Nile Red probe (diOHNR) as the fluorescent label.

Predicting frictional aging from bulk relaxation measurements.

The coefficient of static friction between solids normally increases with the time they have remained in static contact before the measurement. This phenomenon, known as frictional aging, is at the origin of the difference between static and dynamic friction coefficients but has remained difficult to understand. It is usually attributed to a slow expansion of the area of atomic contact as the interface changes under pressure.

Low energy nebulization preserves integrity of SARS-CoV-2 mRNA vaccines for respiratory delivery.

Nebulization of mRNA therapeutics can be used to directly target the respiratory tract. A promising prospect is that mucosal administration of lipid nanoparticle (LNP)-based mRNA vaccines may lead to a more efficient protection against respiratory viruses. However, the nebulization process can rupture the LNP vehicles and degrade the mRNA molecules inside.

Quantitative Understanding of the Onset of Dense Granular Flows.

The question of when and how dense granular materials start to flow under stress, despite many industrial and geophysical applications, remains largely unresolved. We develop and test a simple equation for the onset of quasistatic flows of granular materials which is based on the frictional aging of the granular packing. The result is a nonmonotonic stress-strain relation which-akin to classical friction-is independent of the shear rate.

Surface-Mediated Molecular Transport of a Lipophilic Fluorescent Probe in Polydisperse Oil-in-Water Emulsions.

Emulsions often act as carriers for water-insoluble solutes that are delivered to a specific target. The molecular transport of solutes in emulsions can be facilitated by surfactants and is often limited by diffusion through the continuous phase. We here investigate this transport on a molecular scale by using a lipophilic molecular rotor as a proxy for solutes.