A note on closure properties of the classes of sets accepted by tape-bounded two-dimensional turing machines

For the classes of sets accepted by several tape-bounded two-dimensional Turing machines, we examine closure properties concerning the operations of taking row catenation, column catenation, row closure, column closure, and projection.     

Cyclic closure properties of automata on a two-dimensional tape

In this paper, we investigate cyclic closure properties of several types of automata on a two-dimensional tape. It is shown that (1) the classes of sets accepted by two-dimensional finite automata, deterministic one-way parallel/sequential array automata, and two-dimensional deterministic on-line tessellation acceptors are not closed under row or column cyclic closure, and (2) the class of sets accepted by two-way parallel-sequential array automata is not closed under row cyclic closure.     

Lattice Boltzmann simulation on continuously regenerating diesel filter

To reduce particulate matter (PM) including soot in diesel exhaust gas, a diesel particulate filter (DPF) has been developed. Since it is difficult to observe the phenomena in a DPF experimentally, we have conducted a lattice Boltzmann simulation. In this study, we simulated the flow in a metallic filter. An X-ray computed tomography (CT) technique was applied to obtain its inner structure. The processes of soot deposition and oxidation were included for a continuously regenerating diesel filter. By comparing experimental data, a parameter of soot deposition probability in the numerical model was determined.     

Tobit model analysis of mutations causing haemophilia

Haemophilia A is a genetic disease resulting from deficiency of factor VIII. The database of mutations causing haemophilia A has been developed by the worldwide collaboration. In this study, we predicted the severity of haemophilia A using ordinary least squares regression (OLS) and Tobit model regression in factor VIII. As parameters, we used four physical–chemical parameters of amino acids and the accessible surface area. As the result, there is a difference between OLS and Tobit model analysis in the prediction of haemophilia A severity. We found that the predicted value by Tobit model in severe data is close to the observed value. These results suggest that Tobit model regression analysis is superior to estimating severity of haemophilia A in severe data than OLS.     

Predictive value of vascular endothelial growth factor (VEGF) in metastasis and prognosis of human colorectal cancer

Vascular endothelial growth factor (VEGF) may affect the phenotype of cancer cells, such as growth velocity and metastatic potential, due to its probable multifunctional property including a mitogenic activity for vascular endothelial cells. The present study was designed to investigate the association of VEGF mRNA expression with progression and metastasis of human colorectal cancer. The level of VEGF mRNA expression was quantified by Northern blot hybridization in tumorous and non-tumorous tissues obtained from 60 primary colorectal cancer patients. The ratio of the former to the latter was defined as the VEGF T/N ratio, and the prognostic significance of this ratio, following surgery, in addition to the relationship to progression and metastatic potential, was evaluated. The value of the VEGF T/N ratio was significantly correlated with the depth of tumour infiltration (P=0.046), the incidence of liver metastasis (P < 0.0001) and lymph node metastasis (P=0.036). Patient prognosis was estimated by the Kaplan-Meier method and the log-rank test. When the VEGF T/N ratio was higher than 4.8 for which the chi2 value of the log-rank test was maximal, the tumour was defined as showing overexpression of VEGF mRNA. Patients with overexpression of VEGF mRNA demonstrated poorer survival than patients without overexpression of VEGF mRNA (P < 0.001). The overall estimated hazard ratio for death in patients with overexpression of VEGF mRNA was 1.94 according to a multivariate analysis (P=0.005). Thus, VEGF is associated with the progression, invasion and metastasis of colorectal cancer, and overexpression of VEGF mRNA in the primary tumour is assumed to be closely correlated with poor prognosis in colorectal cancer patients. Moreover, the VEGF T/N ratio may be used as an independent prognostic marker in colorectal cancer patients.     

Shape from interreflections

Shape-from-intensity methods assume that points in a scene are only illuminated by the sources of light. This assumption is valid only when the scene consists of a single convex surface. Most scenes consist of concave surfaces where points reflect light among themselves. In the presence of these interreflections, shape-from-intensity methods produce erroneous (pseudo) estimates of shape and reflectance. This article shows that, for Lambertian surfaces, the pseudo shape and reflectance are unique and can be mathematically related to the actual shape and reflectance of the surface. We present an iterative algorithm that simultaneously recovers the actual shape and reflectance from the pseudo estimates. The general behavior of the algorithm and its convergence properties are discussed. Simulations as well as experimental results are included to demonstrate the accuracy and robustness of the algorithm.     

Role of stearic acid in the strain-induced crystallization of crosslinked natural rubber and synthetic cis-1,4-polyisoprene

Strain-induced crystallization of crosslinked natural rubber (NR) and its synthetic analogue, cis-1,4-polyisoprene (IR), both mixed with various amounts of stearic acid (SA), were investigated by time-resolved X-ray diffraction using a powerful synchrotron radiation source and simultaneous mechanical (tensile) measurement. No acceleration or retardation was observed on NR in spite of the increase of SA amount. Even the SA-free IR crystallized upon stretching, and the overall crystallization behavior of IR shifted to the larger strain ratio with increasing SA content. No difference due to the SA was detected in the deformation of crystal lattice by stress for both NR and IR. These results suggested that the extended network chains are effective for the initiation of crystallization upon stretching, while the role of SA is trivial. These behaviors are much different from their crystallization at low temperature by standing, where SA acts as a nucleating agent.