Low-porosity stents such as flow diverters and the flow isolator, which we developed in a previous study, are expected to provide an effective and minimally invasive treatment for intracranial aneurysms (IAs). After inserting a stent, thrombus formation is promoted by the stagnation of IA blood flow. Consequently, IA embolization can occur. Therefore, IA flow intensity significantly affects IA embolization treatment. IA morphology such as aneurysm size, aspect ratio, and bottleneck factor are important parameters as general indices of IA rupture. Meanwhile, existing literature suggests that IA morphology is considerably affected by IA flow and IA embolization. Hence, this work investigates the relationship between IA flow intensity and IA morphology by using particle imaging velocimetry (PIV) and in vitro flow simulation with IA and parent vessel models. The PIV results showed that the area mean shear rate (AMSR), a hemodynamical index of thrombus formation, was higher in IA models with higher neck widths, lower aneurysm heights, and smaller dome sizes. This implies that thrombus formation is inhibited in a wide-neck and small aneurysm. Moreover, stents with effective flow-reduction properties are required for a reliable IA embolization treatment. The AMSR was well expressed by a power function using the Reynolds number and IA morphology as parameters.

To develop a novel index of body water distribution status in hemodialysis (HD) patients, we derived equations that estimate the excess fluid volume (ExFv) in HD patients, and evaluated their applicability. The ExFv estimation equations were derived based on the correlations between extracellular water (ECW) and total body water (TBW) volumes of healthy adults, which were measured using multifrequency bioelectrical impedance analysis. Here, the effect of increasing ECW/TBW with age was corrected. The estimated ExFv and the circulatory and body fluid status of HD patients were compared between two groups of 20 patients with dry weight (DW) and 16 patients with overhydration (OH), both of which were clinically classified. The indices of circulatory and body fluid status were significantly higher in the OH group than in the DW group. The ExFv values of the DW and OH groups were 0.06 ± 0.19 L and 0.78 ± 0.32 L in males and 0.06 ± 0.16 L and 0.51 ± 0.18 L in females, respectively, indicating significantly higher values in the OH group. The derived ExFv estimation equations allow us a simple and quantitative assessment of the body water distribution status in HD patients.

Erythrocytes are the most abundant cells and acting as carrier, deliverer and sensor of oxygen. Therefore, human erythrocyte behavior is a fundamental health indicator. Lifespan of circulating erythrocytes is about 120 days, and hence erythrocyte population shows distribution of aging. The physicochemical property of hemoglobin (Hb) influences the density and the deformability of erythrocytes. Senescent erythrocytes are dense, shrunk, less deformable and finally removed from circulation by several mechanisms such as phagocytosis and eryptosis. Earlier removal leads to the short lifespan of less deformable erythrocytes. Herein, anemic and cardiometabolic diseases are presented in order to consider the relationship between the age-dependent erythrocyte density and deformability. The main cause of impaired deformability in sickle cell disease is the presence of dense cells characterized by cellular dehydration and polymerization of sickle Hb, that in hereditary hemolytic diseases is cellular geometry, and that in iron deficiency anemia is an increased susceptibility of lighter erythrocytes to the oxidative stress. Diabetic erythrocytes show seemingly normal density and reduced deformability under the enhanced oxidative stress. This article addresses that distribution profiles of both erythrocyte density and deformability are important for better understanding of the encapsulated Hb interacting membrane of erythrocytes showing individual aging.

Aqueous solution of fibrinogen, one of blood clotting factors, forms a fibrin gel by the action of enzyme thrombin. Calcium ions are known to affect not only the gelation kinetics but the structure of fibrin gel network. Dynamic modulus and turbidity have been used to monitor the gelation, however, there are few reports to compare the two data sets. In this study, we have carried out simultaneous measurements of the dynamic modulus and transmitted light intensity during fibrin gelation using a newly developed coaxial-cylinder rotational rheometer with transparent inner and outer cylinders. The measurements for dynamic modulus were carried out at an oscillation frequency of 1 Hz and an oscillation amplitude of 1 mrad in the presence of calcium ions (1–50 mM). After the addition of thrombin to fibrinogen solution, an opaque fibrin gel was formed. The decrease in the transmitted light intensity occurred faster than the increase in the elastic modulus due to the stepwise fibrin polymerization. The time courses of the dynamic moduli and the transmitted light intensity were well expressed using empirical exponential-type equations. The parameters obtained by fitting the data to the equations closely related to the gelation kinetics and the network structure of fibirin. We discuss the effect of calcium ions on the parameters.

Infection control and protection from the emerging diseases should be rationally formulated and operated based on epidemiologically determined infection characteristics. In order to respond to this requirement, this study proposes a mathematical model of the progression of the spread of viral infection in the society. In addition, the model was applied to cases of transmission of the new coronavirus COVID-19. From the results, the following is clarified: the progress of the viral infection can be simply modeled by the daily-rate basic reproduction number r and the infection detection rate k; r is determined by the epidemiologically determined values of basic reproduction number R_o and the infection lifetime T of virus; the daily-rate effective reproduction number r_eff can be defined by r_eff = r(1 – k), and r_eff < 1 indicates that the infection is suppressed; the infection suppression can be realized to make k greater than the critical value k_cr corresponding to the epidemiological parameters; this model fits well with the practical infection behavior of COVID-19 and enables the quantitative evaluation of infection suppress measures; In the case of China, thorough detecting and isolation would have improved the infection condition to the suppression phase after only 10 days.