Takahiro Ezaki 교수

The results of 139 hepatic resections in 154 patients with hepatocellular carcinoma (HCC) operated upon in the last 6 years are reported. These 139 Japanese patients were classified into three groups according to age. Group I included 58 patients under 55 years of age, group II 44 aged from 56 to 65 years and group III 37 aged over 66 years. Fewer cases in group III had histological evidence of cirrhosis than in the other two groups. There was a statistically significant marked decline in the pr

Direct reciprocity, or repeated interaction, is a main mechanism to sustain cooperation under social dilemmas involving two individuals. For larger groups and networks, which are probably more relevant to understanding and engineering our society, experiments employing repeated multiplayer social dilemma games have suggested that humans often show conditional cooperation behavior and its moody variant. Mechanisms underlying these behaviors largely remain unclear. Here we provide a proximate acco

We investigate the dynamics of the evacuation process with multiple bottlenecks using the floor field model. To deal with this problem, we first focus on a part of the system and report its microscopic behavior. The system is controlled by parameters of inflow and the competitiveness of the pedestrians, and large inflow leads to a congested situation. Through simulations, the metastable state induced by conflicts of pedestrians is observed. The metastability is related to the phase transition fr

Cell nuclear DNA content was microspectrophotometrically measured in 60 specimens of clinical hepatocellular carcinoma (HCC). The DNA distribution pattern was classified into two types, diploid and nondiploid, according to the degree of dispersion on the DNA histogram. Among these 60 specimens, 26 had an HCC of less than 5 cm in diameter. In these 26, 17 (65%) had the diploid pattern and 9 (35%) had the nondiploid pattern. In the remaining 34 specimens with a large HCC exceeding 5 cm in diameter

Executive functions, a set of cognitive processes that enable flexible behavioral control, are known to decay with aging. Because such complex mental functions are considered to rely on the dynamic coordination of functionally different neural systems, the age-related decline in executive functions should be underpinned by alteration of large-scale neural dynamics. However, the effects of age on brain dynamics have not been firmly formulated. Here, we investigate such age-related changes in brai

A partial hepatic resection was performed in 13 patients with chronic liver disease using intermittent hepatic inflow occlusion. Eleven patients had liver cirrhosis and two had chronic hepatitis. Seven patients were classified as Child's grade A and six as Child's grade B before operation. Dissection of the hepatic parenchyma was performed during intermittent inflow occlusion. The time of clamping and declamping was 10-20 min and 5-8 min, respectively. Postoperative data on liver function showed

Advanced integration of logistics systems has been promoted for competitiveness and sustainability. Interconnection of transport operations increases complexity at a network level, which reduces the predictability of the response of the system to disruptions. However, our understanding of the behavior of such systems is still limited. In particular, the topology of the network, which changes as the systems are integrated, is an important factor that affects the performance of the entire system.

In this paper, we propose a nonlinear transport model for an aviation network. The takeoff rate from an airport is characterized by the degree of ground congestion. Due to the effect of surface congestion, the performance of an airport deteriorates because of inefficient configurations of waiting aircraft on the ground. Using a simple transport model, we performed simulations on a United States airport network and found a global jamming transition induced by local surface congestion. From a phys

Seven Japanese patients showed a gradual rise in serum alpha-fetoprotein (AFP) levels for periods of 4 to 14 weeks after partial hepatectomy for hepatocellular carcinoma. These levels then gradually decreased, but not always to a normal level, and various procedures after surgery failed to detect tumor recurrence. All the cases were complicated with liver cirrhosis. It is suggested that the postoperative elevation in the AFP level may have been caused by hepatic regeneration as a result of the i

Recent studies have proposed that one can summarize brain activity into dynamics among a relatively small number of hidden states and that such an approach is a promising tool for revealing brain function. Hidden Markov models (HMMs) are a prevalent approach to inferring such neural dynamics among discrete brain states. However, the impact of assuming Markovian structure in neural time series data has not been sufficiently examined. Here, to address this situation and examine the performance of

We have proved an exact solution of a multilane totally asymmetric simple exclusion process (TASEP) with heterogeneous lane-changing rates on a torus. In the expression, the TASEP in each lane and lane-changing transition can be separable. Moreover, the lane-changing transitions satisfy the detailed balance condition, and this is the key to constructing the solution. Using the saddle-point method, the current of particles has been derived in a simple form in a thermodynamic limit. It is interest

We present exact stationary distribution of the asymmetric simple exclusion process with Langmuir kinetics and its related model on a ring. The distribution is expressed in simple factorized forms, that is supported by detailed balance conditions satisfied in the attachment and detachment transitions. Using the equations, we derive the density of particles, the current and the variance of particle numbers in each lane. The expressions for the density are well associated with the ones found in eq

In transportation networks, a spontaneous jamming transition is often observed, e.g. in urban road networks and airport networks. Because of this instability, flow distribution is significantly imbalanced on a macroscopic level. To mitigate the congestion, we consider a simple control method, in which congested nodes are closed temporarily, and investigate how it influences the overall system. Depending on the timing of the node closure and opening, and congestion level of a network, the system