Photochromic Visualization Research Articles

Electron transport chain-inspired coordination polymers for macroscopic spatiotemporal scales of charge separation and transport in photocatalysis.

Classic homogeneous photocatalysis is limited by the temporal transience and the spatial proximity of photoinduced charge separation and transport. The electron transfer chain (ETC) in cellular respiration can mediate unidirectional and long-range electron transfer to isolate the oxidation and reduction centres. Inspired by this, we modified electron-accepting (A) viologen with π-extending thiazolothiazole and electron-donating (D) phenyl carboxylate into a D-A-π-A-D-type ligand and assembled segregated dye stacking in coordination polymer Cd-TzBDP for breaking the spatiotemporal limitation of single-molecule photocatalysis. The offset characteristics of D-A segregated stacking not only allowed the photoinduced-2e- transfer from the D-type carboxylate terminal to the spatially adjacent A-type viologen motif within 1 ps but also permitted the following delocalization of e- and h+ along stacked columns. These advantages endowed Cd-TzBDP with long-lived photochromic visualization of intermittent aerobic photooxidation steps, which enabled the bioinspired ETC-mediated aerobic respiration of mitochondria, achieving the continuous photocatalytic α-C(sp3)-H functionalization of tertiary amines with pharmaceutical interest. Enlightened by ETC-mediated electron leak in hypoxia, the coordination polymer was further employed in a photocatalytic membrane reactor, which visually illustrated the photo-driven cross-membrane long-range transfers of multiple electrons and protons from the hypoxic compartment to normoxic one, benefiting the distal photooxidation and photoreduction with biomimetic compartment selectivity.

Observation of Oil Film Behavior around Microbubbles on Journal Bearings utilizing Photochromic Visualization Technique

Microbubbles have attracted attention as a new friction reduction method for journal bearings. Microbubbles are bubbles with a diameter of 100 μm or less, and it has been suggested that they contribute to friction reduction by deforming and rotating in the bearing clearance, but their behavior during operation is still unclear. Therefore, oil film behavior around microbubbles on journal bearings was observed utilizing a photochromism visualization technique that uses an oil film that changes color when irradiated with ultraviolet light as a tracer. As a result, it was confirmed that the microbubbles flowed in the bearing clearance at approximately half the shaft rotation speed while being stretched into an elliptical shape by the shear of the oil film caused by the rotation of the journal. In addition, when focusing on the behavior of the oil film around the microbubbles, a straight flow was observed, which was thought to be caused by the rotation of the microbubble.

Chemiluminescence-Derived Self-Powered Photoelectrochemical Immunoassay for Detecting a Low-Abundance Disease-Related Protein.

Early diagnosis of cancers relies on the sensitive detection of specific biomarkers, but most of the current testing methods are inaccessible to home healthcare due to cumbersome steps, prolonged testing time, and utilization of toxic and hazardous substances. Herein, we developed a portable self-powered photoelectrochemical (PEC) sensing platform for rapid detection of prostate-specific antigen (PSA, as a model disease-related protein) by integrating a self-powered photoelectric signal output system catalyzed with chemiluminescence-functionalized Au nanoparticles (AuNPs) and a phosphomolybdic acid (PMA)-based photochromic visualization platform. TiO2-g-C3N4-PMA photosensitive materials were first synthesized and functionalized on a sensor chip. The sensor consisted of filter paper modified with a photocatalytic material and a regional laser-etched FTO electrode as an alternative to a conventional PEC sensor with a glass-based electrode. The targeting system involved a monoclonal anti-PSA capture antibody-functionalized Fe3O4 magnetic bead (mAb1-MB) and a polyclonal anti-PSA antibody (pAb2)-N-(4-aminobutyl)-N-ethylisoluminol-AuNP (ABEI-AuNP). Based on the signal intensity of the chemiluminescent system, the photochromic device color changed from light yellow to heteropoly blue through the PMA photoelectric materials integrated into the electrode for visualization of the signal output. In addition, the electrical signal in the PEC system was amplified by a sandwich-type capacitor and readout on a handheld digital multimeter. Under optimum conditions, the sensor exhibited high sensitivity relative to PSA in the range of 0.01-50 ng mL-1 with a low detection limit of 6.25 pg mL-1. The flow-through chemiluminescence reactor with a semiautomatic injection device and magnetic separation was avoid of unstable light source intensity inherent in the chemiluminescence process. Therefore, our strategy provides a new horizon for point-of-care analysis and rapid cost-effective clinical diagnosis.

Observation of Oil Film Behavior in Oil Film Rupture Region on Journal Bearings utilizing Photochromic Visualization Technique

Observation of Oil Film Behavior in Oil Film Rupture Region on Journal Bearings utilizing Photochromic Visualization Technique

フォトクロミズムを用いた可視化手法による ピストン周りのオイル挙動計測 －モータリング低温低速条件下でのピストンランド部オイル挙動－

フォトクロミズムを用いた可視化手法による ピストン周りのオイル挙動計測 －モータリング低温低速条件下でのピストンランド部オイル挙動－

ヘルショウセルによる高分子溶液の伸張粘度測定法の開発(S23-1 複雑流体の流れとその応用(1),S23 複雑流体の流れとその応用)

The Hele-Shaw flows of a Newtonian fluid have been used to reproduce the flow patterns of two-dimensional potential flow. In the earlier papers, the present authors showed effects of elasticity on Hele-Shaw flows around a circular and a square cylinder, and a flow passing through a slit, and presented a new method to estimate the planar extensional viscosity from the slit flow pattern. In this study, the method is improved and tested using four polymer solutions. A new photochromic visualization technique is developed and applied to investigate the velocity field to confirm the validity of the improved method.

Hydrodynamics of Modern Artificial Heart Valves

The results of an experimental investigation of the hydrodynamics of modern artificial heart valves are presented. The photochromic visualization method based on the creation of colored marks in the flow of physiological solution behind the valve is used. The results of an analysis of the hydrodynamic characteristics are presented for the MIKS disk valve (Russia) and the ST. JUDE bileaflet valve (USA) that have been widely used in clinical practice for more than 15 years.

Measurement of the hydrodynamic characteristics of artificial heart valves by photochromic visualization

We propose using photochromic visualization to measure the hydrodynamic characteristics of artificial heart valves under simulated physiological flow conditions. The photochromic visualization method is based on generation of colored markers in the flow behind the artificial heart valve in a time equal to 10−6 to 10−9 sec. We use high-power laser radiation as the source for generating the colored markers.

Experimental investigation of vibroconvection by the photochromic visualization method

The photochromic visualization method has been used to investigate vibroconvection in fluids. The experimental apparatus and the results of observing the flow in rectangular cells are described. The investigations were carried out for various vibration amplitudes, vibrating body dimensions and vibration frequencies. The position and orientation of the vibrating body were varied. A technology for using continuous low-power laser radiation to study slow flows has been developed.

Investigation of hydrodynamic flow inside a disk valve by photochromic visualization

Photochromic visualization has been used to investigate the hydrodynamic flow which arises inside a sliding valve during its operation. The experimental setup and results of observations of the flows are described. Unsteady flows with different amplitudes and frequencies of the oscillations of the flow rate through the valve were investigated. The method makes is possible to determine the flow structure, construct profiles of the velocities and tangential stresses in the complete region within the valve, and also obtain data for calculating the hydrodynamic characteristics of valves.

Investigation of thermoconvective motion of liquid in enclosure by photochromic flow visualization

The method of photochromic visualization is applied to study the thermal convection in liquids. Description of experimental set up and results of observation of the flow field in rectangular cavity, with side heating, in the case of homogeneous liquid and liquid with step-like density stratification are given.

A method for investigating modelled blood flow in stenosed vessels

The method of photochromic visualization (PVC) provides adequate graphical representations of model flow patterns without requiring other additional means of measurement. Medicinal additives as well as an increased degree of stenosis in the model vessel lead to significant changes in flow structure, and increased hydraulic resistance and tangential stress. Analysis of our results indicates that in the real organism, depending upon the condition of the patient's blood, pathological changes in the circulatory system and the quantity of medicinal additives can increase the load on the cardiovascular system. The next important stage of investigation into the characteristics of flow in model vessels by the PVC method is conducting of experiments under pulsatile flow conditions.

An investigation of the motion of homogeneous and stratified liquids in rectangular cavities by the method of photochromic visualization

A method of photochromic visualization has been developed for investigating thermogravitational flows in homogeneous and stratified fluids in a closed volume.

Photochromic visualization for investigation of artificial heart valves.

This report contains results of investigation into hydrodynamics of artificial heart valves by means of photochromic flow visualization (PFV). The PFV method is based on activation of colored tracers in originally colorless photochromic solutions by pulse laser radiation during 10(-6)-10(-9) sec.

Photochromic Visualization for Investigation of Artificial Heart Valves

Photochromic Visualization for Investigation of Artificial Heart Valves

Holographic study of flows with photochromic visualization

Holographic study of flows with photochromic visualization

Use of the method of photochromic visualization to study the constrained flow of a viscous fluid in a pipe

Use of the method of photochromic visualization to study the constrained flow of a viscous fluid in a pipe

Effect of turbulence on the precision of velocity and velocity fluctuation data obtained by photochromic visualization

AbstractEven though photochromic flow visualization has been applied to a large range of flow configurations, no analytical study has been made indicating the effects of turbulence fluctuations on the precision of velocity and turbulence data measured by means of the technique. Because of the quick break up and dispersion of photochromic traces by turbulent eddies in the flow it is useful to know a priori the number of observations from which velocity and turbulence data can be determined with a prefixed precision. The paper presents equations and figures from which this and other useful information may be derived.low Reynolds number and by Seeley et al(5) in their