Synthesis of thermoresponsive copolymer/silica-coated magnetite nanoparticle composite and its application for heavy metal ion recovery

To enhance chemical stability and suppress of aggregation of magnetite nanoparticles (MNPs), which are used as a support for thermoresponsive copolymer immobilization, silica coating of the MNPs is applied via the electrooxidation method. Although the resulting silica coated-MNPs also formed aggregates, the size distribution of the aggregate shifted to smaller size range. Because of that, the surface area available for copolymer immobilization increased approximately 6.7 times at maximum as compared with that of the uncoated MNPs. It contributed to the increase of the amount of the immobilized copolymer on the silica-coated MNPs, which is approximately four times larger than that on the uncoated MNPs. Fe₃O₄ dissolution test confirmed enhancement of chemical stability of MNPs. The thermoresponsive copolymer immobilized on the silica-coated MNPs shows the ability to recycle Cu(II) ion from Cu(II) containing solution by changing temperature with significantly shorter time than those in other thermoresponsive adsorbents in gel form.     

Decomposition of timed automata for solving scheduling problems

A decomposition algorithm for scheduling problems based on timed automata (TA) model is proposed. The problem is represented as an optimal state transition problem for TA. The model comprises of the parallel composition of submodels such as jobs and resources. The procedure of the proposed methodology can be divided into two steps. The first step is to decompose the TA model into several submodels by using decomposable condition. The second step is to combine individual solution of subproblems for the decomposed submodels by the penalty function method. A feasible solution for the entire model is derived through the iterated computation of solving the subproblem for each submodel. The proposed methodology is applied to solve flowshop and jobshop scheduling problems. Computational experiments demonstrate the effectiveness of the proposed algorithm compared with a conventional TA scheduling algorithm without decomposition.     

Detection of a brain aneurysm and a way to search for a brain aneurysm aimed at the development of a system to simulate an operation

In this article, a system is proposed for a simulated operation which would help a trainee surgeon to perform a medical operation to ensure that a cerebral aneurysm does not burst. The physician will have acquired empirical medical technologies from operations in traditional clinical teaching. However, there is a problem with safety and the burden to the patient. Therefore, recently a new training approach for a simulated medical operation using virtual reality has been explored. With the aim of developing a simulated system for a medical operation for a cerebral aneurysm, we considered the necessary functions such as detecting the brain aneurysm that is the target of the operation, and searching for a suitable blood vessel to make a plan for the operation.     

Two conditions concerning common quadratic Lyapunov functions forlinear systems

Concerning a pair of linear systems, some triangle conditions for the existence of a common quadratic Lyapunov function are presented in this paper. These conditions are derived from a criterion for judging the semipositiveness of a linear map defined on symmetric matrices     

A case of infective endocarditis with the mycotic aortic valve aneurysm

A 49-year old man was admitted with a complaint of syncopal attack. Transient A.V block was detected and permanent pacemaker (DDD) was implanted. Five months later he was re-admitted because of dyspnea and palpitation. Infective endocarditis with aortic regurgitation and mycotic aortic valve aneurysm was diagnosed by echocardiography and cineangiography. The aortic valve and valve aneurysm were resected and AVR was performed using Bj?rk-Shiley disc valve (23A) in the usual manner. But 6 months later he suffered from acute cardiac failure due to perivalvular leakage. He died in spite of re-AVR with translocation method.     

A distributed routing method for AGVs under motion delay disturbance

In real transportation environments for semi-conductor manufacturing, unexpected disturbances such as motion delays and/or sudden requests for transportation may cause collisions among AGVs increasing total transportation time. It is required to generate a collision-free routing for multiple automated guided vehicles (AGVs) within a few seconds. In this paper, we propose a distributed routing method under motion delay disturbance for multiple AGVs. The proposed method features a characteristic that each AGV subsystem derives its optimal route to minimize the sum of the transportation time and the penalties with respect to collision probability with other AGVs. The penalties reflect the collision probability distribution function for motion delay disturbances. The proposed method is applied to a routing problem for transportation in the semiconductor fabrication bay with 143 nodes and 20 AGVs. The computational results show that the total transportation time obtained by the proposed method is shorter than that of the conventional method. For dynamic transportation environments, an optimal timing for re-routing multiple AGVs under motion delay disturbance is systematically determined by the tradeoff relationship between the total computation time to derive a solution and the uncertainties for re-routings. Markov chain is used to represent uncertainty distribution for re-routings. The proposed method is implemented in an experimental transportation system with 51 nodes and 5 AGVs. The experimental results demonstrate that the proposed method is applicable to real transportation environments.     

Analysis of ultrasonic welding process of mild steel and 5052 aluminium alloy

Ultrasonic welding of mild steel sheet (SPCC) and aluminium alloy sheet (A5052) was conducted using two different weld tips of a knurled tip (K-tip) and a curved shape tip without knurled edges (C-tip). Behaviours of the weld tip and the welded materials during the weld process were analysed using a high-speed camera observation and an image correlation. The C-tip welding shows a completely different displacement behaviour from the K-tip welding; a relative motion between the tool tip and A5052 in contact with the tip predominantly occurs in the C-tip in contrast to a relative motion between A5052 and SPCC observed in the K-tip. The joint strength using the C-tip was higher than that using the K-tip under the weld conditions in this study. It is demonstrated that the relative motion behaviour in the C-tip causes a macroscopic deformation of A5052 in the vibration direction. This phenomenon promotes growth of a bonded region, resulting in the increase of joint strength. It is surmised that Fe–Al intermetallic layer forms at the weld interface, and the joint strength consequently decreases for the longer weld time condition.     

Autophagic Cell Death and Cancer

Programmed cell death (PCD) is a crucial process required for the normal development and physiology of metazoans. The three major mechanisms that induce PCD are called type I (apoptosis), type II (autophagic cell death), and type III (necrotic cell death). Dysfunctional PCD leads to diseases such as cancer and neurodegeneration. Although apoptosis is the most common form of PCD, recent studies have provided evidence that there are other forms of cell death. One of such cell death is autophagic cell death, which occurs via the activation of autophagy. The present review summarizes recent knowledge about autophagic cell death and discusses the relationship with tumorigenesis.     

Stability of linear discrete dynamics employing state saturation arithmetic

This note is concerned with the stability of discrete-time dynamical systems employing saturation arithmetic in the state-space. A matrix measure is introduced so that it can administer the proximity evaluation of a matrix to the set of diagonal matrices, and the measure is utilized for making an additional condition to the Lyapunov-Stein matrix inequality. The solvability of the modified matrix inequality ensures not only the stability but also the absence of overflow oscillation under the state saturation arithmetic, and this approach has the advantage of being free from auxiliary parameters. As an application, the obtained result is applied to the stability analysis of two-dimensional dynamics. Numerical examples are given to illustrate the results.     

Stability robustness for linear state space models - a Lyapunov mapping approach

Some Pythagorean-like conditions for the existence of a common Lyapunov solution for two given matrices are presented. These conditions are set on the Lyapunov mappings associated with given matrices. The key is the semipositiveness of linear mappings defined on symmetric matrices. From the viewpoint of the existence of a common Lyapunov solution, some known stability robustness results are reviewed and refined.