Vibration-induced acceleration of infiltration in loess

Coupled effects of railway vibration, rainfall, and drying-wetting cycles contribute to new types of loess disasters such as the collapse and vibration-induced settlement of the railway subgrade, loess mass disintegration, and slope sliding,during the large-scale construction and operation of high-speed or heavy-haul railways in China. This has significant consequences for railways that require millimetre-level deformation control, seriously threatening railway operation and people's lives. Therefore, for the first time, "five vibration-induced effects" on loess subjected to vibration, water immersion, and drywetting cycles are discussed including the vibration-induced acceleration of cracking, infiltration, disintegration, sliding, and subsidence. In this paper, the vibration-induced acceleration of infiltration is discussed mainly. The response of loess to locomotive vibration along railways was determined using field sampling and data processing. The dominant frequency of locomotive vibration are 18-22 Hz and the maximum amplitude is 0.4 mm. Tests regarding the vibration-induced acceleration of the permeability were conducted on intact loess using a newly developed vibration permeability apparatus. The results reveal that the vibration accelerates the water permeability and increases the water saturation of loess. The permeability coefficient of saturated loess under vibration is ~1.5-20 times of that without vibration, reaching a maximum at a vibration frequency of 20 Hz.Vibration-induced infiltration tests were carried out on a loess column and the vibration-induced acceleration of water infiltration, wetting front evolution, and air outflow were analysed. The vibration-induced acceleration of infiltration strongly depends on the dry density, vibration frequency, and vibration amplitude. This pioneering work explores the mechnism of loess disasters triggered by locomotive vibration, rainfall, and drying-wetting cycles.

On-chip 3D rotation of oocyte based on a vibration-induced local whirling flow

We propose a novel on-chip 3D cell rotation method based on a vibration-induced flow.When circular vibration is applied to a microchip with micropillar patterns,a highly localized whirling flow is induced around the micropillars.The direction and velocity of this flow can be controlled by changing the direction and amplitude of the applied vibration.Furthermore,this flow can be induced on an open chip structure.In this study,we adopted a microchip with three micropillars arranged in a triangular configuration and an xyz piezoelectric actuator to apply the circular vibration.At the centre of the micropillars,the interference of the vibration-induced flows originating from the individual micropillars induces rotational flow.Consequently,a biological cell placed at this centre rotates under the influence of the flow.Under three-plane circular vibrations in the xy,xz or yz plane,the cell can rotate in both the focal and vertical planes of the microscope.Applying this 3D cell rotation method,we measured the rotational speeds of mouse oocytes in the focal and vertical planes as 63.7±4.0°s^(−1) and 3.5±2.1°s^(−1),respectively.Furthermore,we demonstrated the transportation and rotation of the mouse oocytes and re-positioned their nuclei into a position observable by microscope.

Mitochondria-targeted fluorescent probe based on vibration-induced emission for real-time monitoring mitophagy-specific viscosity dynamic

Directly monitoring mitophagy-specific viscosity dynamic in living cells is of great significance but remains challenging.Herein,this study reported a novel mitochondria-targeted fluorescent probe DPACDY based on vibration-induced emission(VIE)for monitoring viscosity changes during mitochondrial autophagy.This probe contained N,N’-diphenyl-dihydrodibenzo[a,c]phenazine(DPAC)as the VIE core and two positively charged pyridinium moieties for mitochondria anchoring.As the ambient viscosity increased,the vibration of DPAC-DY could be hindered,and subsequently resulting in the enhancement of fluorescence emission.In vitro and intracellular experiments indicated that the probe DPAC-DY showed highly sensitive response to viscosity due to VIE mechanism.Importantly,by virtue of this probe,in situ and real-time visualization of the specific viscosity dynamics during the mitochondrial autophagy process was achieved.Thus,this work provides a novel strategy for VIE-based viscosity response sensors applied to specific organelles and offers a platform for in-depth study of mitochondrial viscosity-related diseases.

Multicolor Circularly Polarized Luminescence of a Single-Component System Revealing Multiple Information Encryption

Metal-free materials with multicolor tunable circularly polarized luminescence(CPL)are attractive because of their potential applications in information storage and encryption.Here,we designed two enantiomers composed of chiral dialkyl glutamides and achiral vibration-induced emission(VIE)moiety,which can switch on CPL after a simple gelation process.It is noteworthy that the CPL colors vary in different solvents,and this is attributed to various self-assembly-induced microstructures,in which the VIE moiety is restrained to different degrees.Accordingly,a multidimensional code system composed of a quick response code,a ultraviolet(UV)light-activated color code,and a CPL information figure was constructed.To our satisfaction,the system possesses multiple information-storage functions.The orthogonal anticounterfeiting and CPLenhanced encryption functions also improve the system information encryption ability.In brief,this study provides a practical example of CPL applied to information security and an effective approach to obtain a single-component color-tunable CPL material with multiple information storage and encryption functions as well.

Tailor-Made Dynamic Fluorophores:Precise Structures Controlling the Photophysical Properties

Organic fluorophores with dynamic conformations in the excited state have played a significant role in applications of organic functional dyes.Among them,dihydrophenazine-based dynamic fluorophores involving a photoinduced structural planarization process in the excited state exhibited large Stokes shifts and conformation-dependent multicolor emissions.With the developments of synthetic strategies,precise modifications on dihydrophenazinebased scaffolds have successfully afforded a variety of precise molecular structures of varying sizes and compositions,which have delicately modulated their photophysical properties.Herein,this Perspective summarizes the precise modulations of dihydrophenazine-based dynamic fluorophores,including the development of the synthetic methodologies,and tailor-made molecular models to reveal the luminescence−structure relationships.

Self-assembled sialyllactosyl probes with aggregation-enhanced properties for ratiometric detection and blocking of influenza viruses

Infection and dissemination of influenza viruses(IVs) causes serious health concerns worldwide.However, effective tools for the accurate detection and blocking of IVs remain elusive. Here, we develop a new sialyllactosyl probe with self-assembled core-shell structure for the ratiometric detection and blocking of IVs. N,N'-diaryl-dihydrodibenzo[a,c]phenazines were used to form the core structure by hydrophobic assembly in an aqueous solution with an aggregation-enhanced blue fluorescence mission.Subsequently, dicyanomethylene-4 H-pyran-based sialyllactosides were used for self-assembly with the core structure, producing the sialyllactosyl probe that emits a red fluorescence due to Forster resonance energy transfer. The probe developed has been proven to be available for(1) the fluorescence ratiometric detection of IVs through selective interaction with the sialyllactosyl-binding proteins on the virus surface,and(2) effectively blocking the invasion of human-infecting IVs towards host cells as accentuated by the sialyllactosides on the surface of the probes.