In vitro confocal micro-PIV measurements of blood flow in a square microchannel: the effect of the haematocrit on instantaneous velocity profiles

A confocal microparticle image velocimetry (micro-PIV) system was used to obtain detailed information on the velocity profiles for the flow of pure water (PW) and in vitro blood (haematocrit up to 17%) in a 100-μm-square microchannel. All the measurements were made in the middle plane of the microchannel at a constant flow rate and low Reynolds number (Re=0.025). The averaged ensemble velocity profiles were found to be markedly parabolic for all the working fluids studied. When comparing the instantaneous velocity profiles of the three fluids, our results indicated that the profile shape depended on the haematocrit. Our confocal micro-PIV measurements demonstrate that the root mean square (RMS) values increase with the haematocrit implying that it is important to consider the information provided by the instantaneous velocity fields, even at low Re. The present study also examines the potential effect of the RBCs on the accuracy of the instantaneous velocity measurements

Determination of blood cells motions and interactions by a confocal micro-PIV system

The development of optical experimental techniques has contributed to obtain explanations on the way the blood flows through microvessels. Although the past results have been encouraging, detailed studies on the flow properties of blood in the microcirculation has been limited by several technical factors such as poor spatial resolution and difficulty to obtain quantitative detailed measurements at such small scales. In recent years, due to advances in computers, confocal microscopy, and digital image processing techniques, it has become possible to combine a micro-particle tracking velocimetry (PTV) system with a confocal microscope. The present study shows for the first time confocal micro-PTV measurements of the dynamic flow behaviour of red blood cells (RBCs) in concentrated suspensions. The measurements were performed at several depths of a 100 um glass capillarie

ネガティブナ ハンスウ ケイコウ ト イカリ ノ カンレン : イカリ ノ ニンチ カンジョウ コウドウ ニ カンスル ケントウ

The purpose of this study was to examine the relationship between the negative rumination trait (NRT) and anger expression as well as examining an influence of the NRT on cognitive and emotional aspects of anger in anger provoking situation. In the experiment, the 18 participants were male undergraduate students. The NRT scale was used to assess the NRT. The participants were divided into two groups (high NRT, low NRT) based on each participants’ score of the NRT scale. An anger provoking situation which was a recorded conversation was presented to the participants. Then, state anger levels and automatic thoughts were measured during anger provoking situations. Results of this study showed that no difference of anger expression and state anger reduced significantly during rumination regardless of high or low NRT. Moreover, automatic thoughts in the anger provoking situations were analyzed using text mining. Result of text mining indicated that the low NRT group judged the situation in an objective perspective. In contrast, the high NRT group set up automatic thoughts about induced-anger and judgments on their situations. From these results, while there was no difference in the duration of state anger, it was suggested that participants had potential to ruminate in cognitive aspects

ダイガクセイ ニオケル スイコウ キノウ ト ショウドウセイ オヨビ テキオウ イヨク ノ カンレン

The purpose of this study was to examine the relationship between executive function, impulsivity, adjustment and motivation in undergraduates. On the first study, we used three self-report scales to measure impulsivity, adjustment and motivation. The results showed that impulsivity influenced lowering of motivation in undergraduates. On the other hand, a decrease in an adjustment couldn’t be explained only by impulsivity. On the second study, the 23 subjects participated in the experiment. In an experiment, we used two laboratory tasks (Go/No-Go task and delay discounting task) and neuropsychological tests (Wisconsin Card Sorting Test, Tower of Hanoi and Operation Span Task) to measure aspects of impulsivity and executive function. Results of this study suggested that impulsivity is associated with a decreased ability to alter choice behavior while functioning adaptively

ジドウ シコウ オヨビ セイリテキ ヘンカ ニオケル シット ト イカリ ノ サイ ノ ケントウ

The purpose of this study was examine to the relationship between anger and jealousy in terms of automatic thoughts and physiological changes. The participants were 37 undergraduate students(14 males and 23 females). Measures used were the enviousness scale for elementary and junior high school pupils and the trait anger scale for the anger scales. The participants were divided into four groups(listed in order to anger, jealousy high-high, high-low, low-high, low-low)on the basis of their average scores on the enviousness scale and the trait anger scale. The participants were presented with anger and jealousy situations which were made into recorded speech. Then,ventricular rate, anger and jealousy levels, and automatic thoughts among presented situation were measured. Results showed that the ventricular rate in anger, jealousy situation were higher than the ventricular rate at rest. Moreover the ventricular rate in anger situation tended to be higher than in jealousy situations. Additionally, automatic thoughts at anger and jealousy situation were analyzed by text mining. Many of the automatic thoughts in anger situations were related to other people, and many of the automatic thoughts in jealousy situations were related to oneself, followed by a relation to others as a comparison. From these results, there was a difference between automatic thoughts in anger situation and automatic thoughts in jealousy situations. Plutichilk(1980) pointed out that feelings other than the fundamental feelings were produced by a combination of fundamental feelings or fundamental feeling combined with other components. This study suggested that jealousy was evoked with anger through comparison with others

Measurement of individual red blood cell motions under high hematocrit conditions using a confocal micro-PTV system

Developments in optical experimental techniques have helped in elucidating how blood flows through microvessels. Although initial developments were encouraging, studies on the flow properties of blood in microcirculation have been limited by several technical factors, such as poor spatial resolution and difficulty obtaining quantitative detailed measurements at such small scales. Recent advances in computing, microscopy, and digital image processing techniques have made it possible to combine a particle tracking velocimetry (PTV) system with a confocal microscope. We document the development of a confocal micro-PTV measurement system for capturing the dynamic flow behavior of red blood cells (RBCs) in concentrated suspensions. Measurements were performed at several depths through 100-mm glass capillaries. The confocal micro-PTV system was able to detect both translational and rotational motions of individual RBCs flowing in concentrated suspensions. Our results provide evidence that RBCs in dilute suspensions (3% hematocrit) tended to follow approximately linear trajectories, whereas RBCs in concentrated suspensions (20% hematocrit) exhibited transversal displacements of about 2% from the original path. Direct and quantitative measurements indicated that the plasma layer appeared to enhance the fluctuations in RBC trajectories owing to decreased obstruction in transversal movements caused by other RBCs. Using optical sectioning and subsequent image contrast and resolution enhancement, the system provides previously unobtainable information on the motion of RBCs, including the trajectories of two or more RBCs interacting in the same focal plane and RBC dispersion coefficients in different focal planes

Radial dispersion of red blood cells in blood flowing through glass capillaries: the role of hematocrit and geometry

The flow properties of blood in the microcirculation depend strongly on the hematocrit (Hct), microvessel geometry, and cell properties. Previous in vitro studies have measured the radial displacement of red blood cells (RBCs) at concentrated suspensions using conventional microscopes. However, to measure the RBCs motion they used transparent suspensions of ghost red cells, which may have different physical properties than normal RBCs. The present study introduces a new approach (confocal micro-PTV) to measure the motion of labeled RBCs flowing in concentrated suspensions of normal RBCs. The ability of confocal systems to obtain thin infocus planes allowed us to measure the radial position of individual RBCs accurately and to consequently measure the interaction between multiple labeled RBCs. All the measurements were performed in the center plane of both 50 mm and 100 mm glass capillaries at Reynolds numbers (Re) from 0.003 to 0.005 using Hcts from 2 to 35%. To quantify the motion and interaction of multiple RBCs, we used the RBC radial dispersion (Dyy). Our results clearly demonstrate that Dyy strongly depends on the Hct. The RBCs exhibited higher Dyy at radial positions between 0.4 R and 0.8 R and lower Dyy at locations adjacent to the wall (0.8 R–1 R) and around the middle of the capillary (0 R–0.2 R). The present work also demonstrates that Dyy tends to decrease with a decrease in the diameter. The information provided by this study not only complements previous investigations on microhemorheology of both dilute and concentrated suspensions of RBCs, but also shows the influence of both Hct and geometry on the radial dispersion of RBCs. This information is important for a better understanding of blood mass transport mechanisms under both physiological and pathological conditions

スイコウ キノウ ガ イカリ カンキジ ノ イカリ ノ テイド オヨビ コウドウ ヨクセイ ニ オヨボス エイキョウ

The purpose of this study was to examine the influence of executive functions on the intensity of anger and on the inhibitory control over feelings of anger. The participants comprised 13 undergraduate students (6 males and 7 females). Measures used were the Behavioural Assessment of the Dysexecutive Syndrome (BADS) for executive functions, the trait and state anger scales for anger, and the go/no-go task for inhibitory control. The participants were divided into two groups (high or low executive functions) on the basis of their average scores (± 1/2 SD) on the BADS. The participants were presented with anger-inducing situations that were made into recorded speech. Then, the anger levels within the presented situations and the inhibitory control that was exhibited after the situations were measured. This study suggested that the average anger levels among the high executive functions group were lower than the anger levels of the low executive functions group. In addition, the anger levels after the go/no-go task were observed to be lower in the high executive functions group than in the low executive functions group. These results suggest a difference in anger levels between the high and low executive functions groups in the same anger-inducing situations as well as after problem solving

Velocity fields of blood flow in microchannels using a confocal micro-PIV system

The in vitro experimental investigations provide an excellent approach to understand complex blood flow phenomena involved at a microscopic level. This paper emphasizes an emerging experimental technique capable to quantify the flow patterns inside microchannels with high spatial and temporal resolution. This technique, known as confocal micro-PIV, consists of a spinning disk confocal microscope, high speed camera and a diode-pumped solid state (DPSS) laser. Velocity profiles of pure water (PW), physiological saline (PS) and in vitro blood were measured in a 100mm glass square and rectangular polydimethysiloxane (PDMS) microchannel. The good agreement obtained between measured and estimated results suggests that this system is a very promising technique to obtain detail information about micro-scale effects in microchannels by using both homogeneous and non-homogeneous fluids such as blood flow.This study was supported in part by the following grants: 21st Century COE Program for Future Medical Engineering based on Bio-nanotechnology, International Doctoral Program in Engineering from the Ministry of Education, Culture, Sports, Science and Technology of Japan (MEXT), “Revolutionary Simulation Software (RSS21)” next-generation IT program of MEXT; Grants-in-Aid for Scientific Research from MEXT and JSPS Scientific Research in Priority Areas (768) “Biomechanics at Micro- and Nanoscale Levels,” Scientific Research (A) No.16200031 “Mechanism of the formation, destruction, and movement of thrombi responsible for ischemia of vital organs.” The authors also thank all members of Esashi, Ono and Tanaka Lab. for their assistance in fabricating the PDMS microchannel

ダイガクセイ ニオケル テキイ キゾク バイアス ト ニンチ キノウ ノ カンレン

This study examined relationship among hostile attributional bias, anger and cognitive function. In the study 1, we examined relationship between hostile attributional bias and states of anger in university students. As a result, the hostility attribution bias of college students was confirmed. Because there was university students who indicated high hostility attribution in an unclear intention of the other. In addition, the tendency of the university stude nt’s intention attribution is significantly higher in when the other is acquaintance. And, it was indicated that the university students showed more strong hostility attribution bias to friends than the others. A positive correlation was found between hostility attribution bias and state anger. It was shown that the hostility attributable bias group often experiences hostile interpretation, anger feeling even in daily life. In Study 2, we examined the relationship between execution function, hostility attribution bias and anger expression. As the result, high cognitive flexibility group indicated significantly higher score than the low group in unintentional attribution. We examined the relationship between performance function and anger expression, but no significant difference was found. From these results, it is considered that the high cognitive flexibility group can be made various intention attributions in a situation where the intention of the other is unclear