Continuous inertial alignment and isolation of spherical microparticles and nonspherical flagellate microalgae.

Flagellate microalgae play an increasingly significant role in environmental management and biotechnology for valuable bioproducts, excellent photosynthetic capability, and autonomic movement. However, multiple flagellate microalgae practically live together in the ocean and lake areas, and they are susceptible to contamination as a result of improper operations. Enthused by these aspects, we develop a reliable inertial microfluidic method to overcome the influence of flagella movement and non-spherical shape on the alignment and isolation of target flagellate microalgae.

Surface topology of MXene flakes induces the selection of the sintering mechanism for supported Pt nanoparticles.

Sintering of metal nanocatalysts leading to particle growth and subsequent performance deactivation is a primary issue that hinders their practical applications. While metal-support interaction (MSI) is considered as the critical factor which influences the sintering behavior, the underlying microscopic mechanism and kinetics remain incompletely understood. Here, by using scanning transmission electron microscopy (STEM) and theoretical analysis, we reveal the selection rule of the sintering mechanism for Pt nanoparticles on a two-dimensional (2D) MXene (TiCT ) support, which relies on the surface topology of MXene flakes.

Significant hydrogen generation photo-mechanical coupling in flexible methylammonium lead iodide nanowires.

The flexoelectric effect, which refers to the mechanical-electric coupling between strain gradient and charge polarization, should be considered for use in charge production for catalytically driving chemical reactions. We have previously revealed that halide perovskites can generate orders of higher magnitude flexoelectricity under the illumination of light than in the dark. In this study, we report the catalytic hydrogen production by photo-mechanical coupling involving the photoflexoelectric effect of flexible methylammonium lead iodide (MAPbI) nanowires (NWs) in hydrogen iodide solution.

Dynamic Observations on Formation of Coffee-Ring Structures from the Degradation of Cesium Lead Halide Perovskite Nanocrystals.

Nanomaterials of halide perovskites have attracted increasing attention for their remarkable potential in optoelectronic devices, but their instability to environmental factors is the core issue impeding their applications. In this context, the microscopic understanding of their structural degradation mechanisms upon external stimuli remains incomplete. Herein, we took an emerging member of this material family, CsPbBr nanocrystals (NCs), as an example and investigated the degradation pathways as well as underlying mechanisms under an electron beam by using in situ transmission electron microscopy.

TiOnanotubes induce early mitochondrial fission in BMMSCs and promote osseointegration.

Nanotopography can promote osseointegration, but how bone marrow mesenchymal stem cells (BMMSCs) respond to this physical stimulus is unclear. Here, we found that early exposure of BMMSCs to nanotopography (6 h) caused mitochondrial fission rather than fusion, which was necessary for osseointegration. We analyzed the changes in mitochondrial morphology and function of BMMSCs located on the surfaces of NT100 (100 nm nanotubes) and ST (smooth) by super-resolution microscopy and other techniques.

Biomimetic Mineralized Fiber Bundle-Inspired Scaffolding Surface on Polyetheretherketone Implants Promotes Osseointegration.

The stress shielding effect caused by traditional metal implants is circumvented by using polyetheretherketone (PEEK), due to its excellent mechanical properties; however, the biologically inert nature of PEEK limits its application. Endowing PEEK with biological activity to promote osseointegration would increase its applicability for bone replacement implants. A biomimetic study is performed, inspired by mineralized collagen fiber bundles that contact bone marrow mesenchymal stem cells (BMMSCs) on the native trabecular bone surface.

Angelica Yinzi alleviates 1-chloro-2,4-dinitrobenzene-induced atopic dermatitis by inhibiting activation of NLRP3 inflammasome and down-regulating the MAPKs/NF-kB signaling pathway.

Background: Atopic dermatitis (AD), characterized by eczema as a chronic pruritic inflammatory skin disease, has become a serious health problem with recurrent clinical episodes. However, current clinical treatments have limited relief and are accompanied by adverse effects. Therefore, there is a necessity to develop new effective drugs for AD treatment.

Atomic-scale mechanisms on the stepwise growth of MoWS into hexagonal flakes.

The systematic transmission electron microscopy (TEM) analysis suggests three stepwise formation stages during the growth of MoWS hexagonal flakes, which are the initial assembly of precursors into vertical structures, subsequent transition into horizontal structures, and final surface relaxing and faceting into hexagonal flakes.

Few-Layered MnAlS Dielectrics for High-Performance van der Waals Stacked Transistors.

The gate dielectric layer is an important component in building a field-effect transistor. Here, we report the synthesis of a layered rhombohedral-structured MnAlS crystal, which can be mechanically exfoliated down to the monolayer limit. The dielectric properties of few-layered MnAlS flakes are systematically investigated, whereby they exhibit a relative dielectric constant of over 6 and an electric breakdown field of around 3.

Multistep nucleation visualized during solid-state crystallization.

Mechanisms of nucleation have been debated for more than a century, despite successes of classical nucleation theory. The nucleation process has been recently argued as involving a nonclassical mechanism (the "two-step" mechanism) in which an intermediate step occurs before the formation of a nascent ordered phase. However, a thorough understanding of this mechanism, in terms of both microscopic kinetics and thermodynamics, remains experimentally challenging.

Strontium-loaded titanium implant with rough surface modulates osseointegration by changing sfrp4 in canonical and noncanonical Wnt signaling pathways.

A rough morphology and strontium (Sr) can activate the Wnt pathway to regulate bone mesenchymal stem cells (rBMSCs) osteogenic differentiation, but the mechanism remains unclear. We constructed smooth Ti (ST) surfaces, rough Ti (RT) surfaces subjected to hydrofluoric acid etching, strontium-loaded smooth Ti (ST-Sr) surfaces subjected to magnetron sputtering, and rough strontium-loaded Ti (RT-Sr) surfaces. We systematically studied theosteogenic differentiation of rBMSCs on these four surfaces by alkaline phosphatase measurement, Alizarin Red staining and polymerase chain reaction (PCR).

Visualization of Bubble Nucleation and Growth Confined in 2D Flakes.

The nucleation and growth of bubbles within a solid matrix is a ubiquitous phenomenon that affects many natural and synthetic processes. However, such a bubbling process is almost "invisible" to common characterization methods because it has an intrinsically multiphased nature and occurs on very short time/length scales. Using in situ transmission electron microscopy to explore the decomposition of a solid precursor that emits gaseous byproducts, the direct observation of a complete nanoscale bubbling process confined in ultrathin 2D flakes is presented here.

Atomic Steps Induce the Aligned Growth of Ice Crystals on Graphite Surfaces.

Heterogeneous ice nucleation on atmospheric aerosols strongly affects the earth's climate, and at the microscopic level, surface-irregularity-induced ice crystallization behaviors are common but crucial. Because of the lack of visual evidence and effective experimental methods, the mechanism of atomic-structure-dependent ice formation on aerosol surfaces is poorly understood. Here we chose highly oriented pyrolytic graphite (HOPG) to represent soot (a primary aerosol), and environmental scanning electron microscopy (ESEM) was performed for in situ observations of ice formation.

Highly Efficient Porous Carbon Electrocatalyst with Controllable N-Species Content for Selective CO Reduction.

We report a straightforward strategy to design efficient N doped porous carbon (NPC) electrocatalyst that has a high concentration of easily accessible active sites for the CO reduction reaction (CO RR). The NPC with large amounts of active N (pyridinic and graphitic N) and highly porous structure is prepared by using an oxygen-rich metal-organic framework (Zn-MOF-74) precursor. The amount of active N species can be tuned by optimizing the calcination temperature and time.

Test-retest reliability of selected items of Health Behaviour in School-aged Children (HBSC) survey questionnaire in Beijing, China.

Background: Children's health and health behaviour are essential for their development and it is important to obtain abundant and accurate information to understand young people's health and health behaviour. The Health Behaviour in School-aged Children (HBSC) study is among the first large-scale international surveys on adolescent health through self-report questionnaires. So far, more than 40 countries in Europe and North America have been involved in the HBSC study.