Monte Carlo Simulation with Asymptotic Method (Published in "Journal of Japan Statistical Society", Vol.35-2, 171-203, 2005. )

We shall propose a new computational scheme with the asymptotic method to achieve variance reduction of Monte Carlo simulation for numerical analysis especially in finance. We not only provide general scheme of our method, but also show its effectiveness through numerical examples such as computing optimal portfolio and pricing an average option. Finally, we show mathematical validity of our method.

"An Asymptotic Expansion Scheme for the Optimal Investment Problems"

We shall propose a new computational scheme for the evaluation of the optimal portfolio for investment.Our method is based on an extension of the asymptotic expansion approach which has been recently developed for pricing problems of the contingent claims' analysis by Kunitomo-Takahashi (1992, 1995, 1998, 2001), Yoshida (1992), Takahashi (1995, 1999),Takahashi and Yoshida (2001). In particular, we will explicitly derive a formula of the optimal portfolio associated with maximizing utility from terminal wealth in a nancial market with Markovian coe cients,and give a numerical example for a power utility function.

Phototactic and Geotactic Responses of the Tea Red Mite, Tetranychus kanzawai (KISHIDA) (Acarina:Tetranychidae)

Phototactic and geotactic responses of the tea red spider mite, Tetranychus kanzawai (KISHIDA) were investigated at 25℃ and about 40 per cent R. H. Twenty adult females of the mite were placed in the middle of a test tube, 2 cm diameter and 20 cm height. The tube was set horizontally or vertically 50 cm apart from the light source putting on the side. The tube was divided into 9 sections putting a mark. The individual number of the mites in each section was counted 0, 1, 2, 3, 4, 5, 10, 15, 20, 25, and 30 minutes after switching on the light. Each test was replicated four times. The mites moved towards the brightest or the highest part of the tube actively at first and more slowly after ten minutes. It was demonstrated that the mites made photopositive and geonegative responses

Tunable defect modes in chiral liquid crystals based on laser-induced modulation of helix

NanoScience + Engineering, 2007, San Diego, California, United StatesHiroyuki Yoshida, Chee Heng Lee, Yusuke Miura, Akihiko Fujii, and Masanori Ozaki "Tunable defect modes in chiral liquid crystals based on laser-induced modulation of helix", Proc. SPIE 6640, Active Photonic Crystals, 664008 (25 September 2007). DOI: https://doi.org/10.1117/12.73348

Tuberculous Cold Abscess in the Axillary Lymph Nodes

Article信州医学雑誌 60(5): 257-259(2012)journal articl

Newly established cell lines from mouse oral epithelium regenerate teeth when combined with dental mesenchyme

The present study attempted to examine whether clonal cell lines of the oral epithelium can differentiate into ameloblasts and regenerate tooth when combined with dental germ mesenchyme. Clonal cell lines with a distinct morphology were established from the oral epithelium of p53-deficient fetal mice at embryonic day 18 (E18). The strain of mouse is shown to be a useful source for establishing clonal and immortalized cell lines from various tissues and at various stages of development. Tooth morphogenesis is almost completed and the oral epithelium is segregated from the dental epithelium at E18. In RT-PCR analysis of cell lines, mucosal epithelial markers (cytokeratin 14) were detected, but ameloblast markers such as amelogenin and ameloblastin were not detected when cells were cultured on plastic dish. They formed stratified epithelia and expressed a specific differentiation marker (CK13) in the upper layer when cultured on feeder layer or on collagen gel for 1–3 wk, demonstrating that they are of oral mucosa origin. Next, bioengineered tooth germs were prepared with cell lines and fetal molar mesenchymal tissues and implanted under kidney capsule for 2–3 wk. Five among six cell lines regenerated calcified structures as seen in natural tooth. Our results indicate that some oral epithelial cells at E18 possess the capability to differentiate into ameloblasts. Furthermore, cell lines established in the present study are useful models to study processes in tooth organogenesis and tooth regeneration