In vivo monitoring of intracellular chloroplast movements in intact leaves of C4 plants using two-photon microscopy.

Dynamic changes in the spatial distribution of chloroplasts are essential for optimizing photosynthetic capacity under changing light conditions. Light-induced movement of chloroplasts has been widely investigated, but most studies were conducted on isolated tissues or protoplasts. In this study, a two-photon microscopy (TPM) system was adapted to monitor the intracellular 3-dimensional (3D) movements of chloroplasts in intact leaves of plants during dark to light transitions.

Effect of pulsatile swirling flow on stenosed arterial blood flow.

The existence of swirling flow phenomena is frequently observed in arterial vessels, but information on the fluid-dynamic roles of swirling flow is still lacking. In this study, the effects of pulsatile swirling inlet flows with various swirling intensities on the flow field in a stenosis model are experimentally investigated using a particle image velocimetry velocity field measurement technique. A pulsatile pump provides cyclic pulsating inlet flow and spiral inserts with two different helical pitches (10D and 10/3D) induce swirling flow in the stenosed channel.

Interactive ion-mediated sap flow regulation in olive and laurel stems: physicochemical characteristics of water transport via the pit structure.

Sap water is distributed and utilized through xylem conduits, which are vascular networks of inert pipes important for plant survival. Interestingly, plants can actively regulate water transport using ion-mediated responses and adapt to environmental changes. However, ionic effects on active water transport in vascular plants remain unclear.

Detection of heparin in the salivary gland and midgut of Aedes togoi.

Mosquitoes secrete saliva that contains biological substances, including anticoagulants that counteract a host's hemostatic response and prevent blood clotting during blood feeding. This study aimed to detect heparin, an anticoagulant in Aedes togoi using an immunohistochemical detection method, in the salivary canal, salivary gland, and midgut of male and female mosquitoes. Comparisons showed that female mosquitoes contained higher concentrations of heparin than male mosquitoes.

Bubble-free and pulse-free fluid delivery into microfluidic devices.

The bubble-free and pulse-free fluid delivery is critical to reliable operation of microfluidic devices. In this study, we propose a new method for stable bubble-free and pulse-free fluid delivery in a microfluidic device. Gas bubbles are separated from liquid by using the density difference between liquid and gas in a closed cavity.

Experimental analysis of the liquid-feeding mechanism of the butterfly Pieris rapae.

The butterfly Pieirs rapae drinks liquid using a long proboscis. A high pressure gradient is induced in the proboscis when cibarial pump muscles contract. However, liquid feeding through the long proboscis poses a disadvantage of high flow resistance.

Study on the deformation of endothelial cells using a bio-inspired in vitro disease model.

A bio-inspired in vitro disease model was developed to investigate the basic biophysics of atherosclerotic diseases. In vivo study was conducted in advance using zebrafish fed with a normal diet and a cholesterol-enriched diet. The endothelial cells (ECs) of the zebrafishes fed with a normal diet are tightly attached and aligned.

Proposal for a new therapy for drug-resistant malaria using Plasmodium synthetic lethality inference.

Many antimalarial drugs kill malaria parasites, but antimalarial drug resistance (ADR) and toxicity to normal cells limit their usefulness. To solve this problem, we suggest a new therapy for drug-resistant malaria. The approach consists of data integration and inference through homology analysis of yeast-human-Plasmodium.

Liquid-intake flow around the tip of butterfly proboscis.

Butterflies drink liquid through a slender proboscis using a large pressure gradient induced by the systaltic operation of a muscular pump inside their head. Although the proboscis is a naturally well-designed coiled micro conduit for liquid uptake and deployment, it has been regarded as a simple straw connected to the muscular pump. There are few studies on the transport of liquid food in the proboscis of a liquid-feeding butterfly.

A microfluidic device for simultaneous measurement of viscosity and flow rate of blood in a complex fluidic network.

Blood viscosity has been considered as one of important biophysical parameters for effectively monitoring variations in physiological and pathological conditions of circulatory disorders. Standard previous methods make it difficult to evaluate variations of blood viscosity under cardiopulmonary bypass procedures or hemodialysis. In this study, we proposed a unique microfluidic device for simultaneously measuring viscosity and flow rate of whole blood circulating in a complex fluidic network including a rat, a reservoir, a pinch valve, and a peristaltic pump.

Label-free viscosity measurement of complex fluids using reversal flow switching manipulation in a microfluidic channel.

The accurate viscosity measurement of complex fluids is essential for characterizing fluidic behaviors in blood vessels and in microfluidic channels of lab-on-a-chip devices. A microfluidic platform that accurately identifies biophysical properties of blood can be used as a promising tool for the early detections of cardiovascular and microcirculation diseases. In this study, a flow-switching phenomenon depending on hydrodynamic balancing in a microfluidic channel was adopted to conduct viscosity measurement of complex fluids with label-free operation.

Blood viscoelasticity measurement using steady and transient flow controls of blood in a microfluidic analogue of Wheastone-bridge channel.

Accurate measurement of blood viscoelasticity including viscosity and elasticity is essential in estimating blood flows in arteries, arterials, and capillaries and in investigating sub-lethal damage of RBCs. Furthermore, the blood viscoelasticity could be clinically used as key indices in monitoring patients with cardiovascular diseases. In this study, we propose a new method to simultaneously measure the viscosity and elasticity of blood by simply controlling the steady and transient blood flows in a microfluidic analogue of Wheastone-bridge channel, without fully integrated sensors and labelling operations.

Effect of swirling inlet condition on the flow field in a stenosed arterial vessel model.

Blood flow in an artery is closely related to atherosclerosis progression. Hemodynamic environments influence platelet activation, aggregation, and rupture of atherosclerotic plaque. The existence of swirling flow components in an artery is frequently observed under in vivo conditions.

Microfluidic biosensor for monitoring temporal variations of hemorheological and hemodynamic properties using an extracorporeal rat bypass loop.

In this study, we propose a novel microfluidic biosensor for monitoring hemorheological and hemodynamic properties using an extracorporeal rat bypass loop. To monitor temporal variations of biophysical properties including viscosity, flow rate, and pressure of rat blood, a complex fluidic network is established by connecting the abdominal aorta and jugular vein to an extracorporeal bypass loop including a flow stabilizer and a microfluidic biosensor. Three biophysical properties are simultaneously measured through label-free operation and sensorless detection based on two sequential flow controls in the microfluidic channel.

X-ray CT and histological imaging of xylem vessels organization in Mimosa pudica.

Mimosa pudica has three distinct specialized organs, namely, pulvinus, secondary pulvinus, and pulvinule, which are respectively controlling the movements of petioles, leaflets, and pinna in response to external stimuli. Water flow is a key factor for such movements, but detailed studies on the organization of the vascular system for water transport in these organs have not been published yet. In this study, organizations of the xylem vessels and morphological features of the pulvinus, the secondary pulvinus, and the pulvinule were experimentally investigated by X-ray computed tomography and histological technique.

In vivo measurement of blood flow in a micro-scale stenosis model generated by laser photothermal blood coagulation.

Blood flow in a stenosed vessel is one of the most important issues, because it is closely related to the outbreak of circulatory diseases. To overcome the technological limitations encountered in the haemodynamic studies using in vitro stenosis models, the authors induced a stenosed flow model in the extraembryonic vessels of a chicken embryo. Blood was coagulated by laser irradiation to artificially form a stenosis on the designated spot in a straight blood vessel.

Improvement of ultrasound speckle image velocimetry using image enhancement techniques.

Ultrasound-based techniques have been developed and widely used in noninvasive measurement of blood velocity. Speckle image velocimetry (SIV), which applies a cross-correlation algorithm to consecutive B-mode images of blood flow has often been employed owing to its better spatial resolution compared with conventional Doppler-based measurement techniques. The SIV technique utilizes speckles backscattered from red blood cell (RBC) aggregates as flow tracers.

Hydraulic characteristics of water-refilling process in excised roots of Arabidopsis.

Plants have efficient water-transporting vascular networks with a self-recovery function from embolism, which causes fatal discontinuity in sap flow. However, the embolism-refilling process in xylem vessel is still unclear. The water-refilling processes in the individual xylem vessels of excised Arabidopsis roots were visualized in this study using synchrotron X-ray micro-imaging technique with high spatial resolution up to 1 μm per pixel and temporal resolution up to 24 fps.

Quantitative visualization of a gas diffusion layer in a polymer electrolyte fuel cell using synchrotron X-ray imaging techniques.

A gas diffusion layer (GDL) in a polymer electrolyte fuel cell (PEFC) is quantitatively visualized using synchrotron X-ray micro-computed tomography. For three-dimensional reconstruction, an adaptive threshold method is used. This method is compared with the conventional method, i.

Aberration compensation for objective phase curvature in phase holographic microscopy.

In this study, we proposed a simple and fast numerical approach to compensate for aberrations induced by objective phase curvature. This method is based on the extraction of virtual background phase from reconstructed phase values using a line profile, followed by subtraction of the virtual background phase from the reconstructed phase image. The performance and feasibility of the method were demonstrated by applying it to the phase imaging of polystyrene microspheres and red blood cells.

Inertial migration of erythrocytes in low-viscosity and high-shear rate microtube flows: application of simple digital in-line holographic microscopy.

A simple digital in-line holographic microscopy technique is applied to investigate the inertial migration of human erythrocytes in low-viscosity and high-shear rate microtube flows. The technique provides radial distribution statistics of the erythrocytes, as well as their orientation information in the tube flow. The radial distribution of human erythrocytes is found to be similar to that of spherical particles of 7 μm in diameter.

Note: development of a compact x-ray particle image velocimetry for measuring opaque flows. II. Three-dimensional velocity field reconstruction.

An x-ray particle image velocimetry (PIV) system using a cone-beam type x-ray was developed. The field of view and the spatial resolution are 36 × 24.05 mm(2) and 20 μm, respectively.

Extracorporeal bypass model of blood circulation for the study of microvascular hemodynamics.

Many studies have been performed to better understand the hemodynamics in microvessels, such as arterioles and venules. However, due to the heterogeneous features of size, shape, blood-flow velocity, and pulsatility of microvessels, conducting a systematic study on these factors has been almost impossible. Although in vitro studies have been performed for this purpose, the usefulness of in vitro data is limited by the fact that the rheological properties of blood are changed as blood is exposed to in vitro environments.

Simultaneous measurement of red blood cell aggregation and whole blood coagulation using high-frequency ultrasound.

This study aims to investigate the feasibility of using high-frequency ultrasound (HFUS) for simultaneous monitoring of blood coagulation and red blood cell (RBC) aggregation. Using a 35-MHz ultrasound scanner, ultrasound speckle data were acquired from whole blood samples of three experimental groups of rats, including 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS)-treated, noncoagulation and normal control groups. The variations of blood echogenicity, the shape parameters of probability distribution of speckle intensity (skewness and kurtosis) and the correlation coefficient between two consecutive speckle data were calculated as a function of time starting from immediately after taking blood.

Imaging efficiency of an X-ray contrast agent-incorporated polymeric microparticle.

Biocompatible polymeric encapsulants have been widely used as a delivery vehicle for a variety of drugs and imaging agents. In this study, X-ray contrast agent (iopamidol) is encapsulated into a polymeric microparticle (polyvinyl alcohol) as a particulate flow tracer in synchrotron X-ray imaging system. The physical properties of the designed microparticles are investigated and correlated with enhancement in the imaging efficiency by experimental observation and theoretical interpretation.