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Search Results: 1 - 10 of 1718 matches for " Tomoyuki Taniguchi "
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The histone deacetylase inhibitor trichostatin A induces cell cycle arrest and rapid upregulation of gadd45β in LS174T human colon cancer cells  [PDF]
Tomoyuki Taniguchi, Jun Iwashita, Jun Murata, Kenji Ueda, Tatsuya Abe
Advances in Biological Chemistry (ABC) , 2012, DOI: 10.4236/abc.2012.21005
Abstract: Histone deacetylase (HDAC) inhibitors are considered as promising therapeutic agents against several malignant diseases because they inhibit cancer cell proliferation. The stress sensor genes of the growth arrest and DNA damage-inducible protein (gadd45) family exhibit disordered expression in several types of malignant diseases and are thus a novel target for cancer therapy. However, there have been only few investigations of whether HDAC inhibitors affect the expression of gadd45 genes. We examined the effects of a HDAC inhibitor, trichostatin A (TSA), on the time-dependent expression of gadd45 genes in the human colon cancer cell line LS174T. Addition of TSA to LS174T cells induced inhibition of cell proliferation by arresting the cell cycle. We found that TSA treatment of LS174T cells induced rapid upregulation of gadd45β mRNA expression within 15 min, reaching a peak level at 3 h. Although the time-dependent expression pattern of gadd45β mRNA was similar to that of gadd45β mRNA, the peak level of gadd45β was lower than that of gadd45β. TSA treatment also upregulated the mRNA level of p21Waf1/Cip1, a prolif- eration inhibitor, after 3 h, but downregulated the mRNA levels of cyclin D1, a proliferation inducer, after 3 h, and of c-Myc after 1 h. TSA treatment induced a certain level of apoptosis, but the mRNA level of p53, a potent apoptosis inducer, was down-regulated after 3 h. These results suggest that the up-regulation of p21Waf1/Cip1 and apoptosis was independent of p53 and that the early upregulation of gadd45β gene, which precedes the upregulation of p21Waf1/Cip1 and the downregulation of cyclin D1, are important in TSA-treated LS174T cells.
The Different Expressions of Draft Cherry Tomato Growth, Yield, Quality under Bamboo and Rice Husk Biochars Application to Clay Loamy Soil  [PDF]
Tran Thi Thu Hien, Yoshiyuki Shinogi, Tomoyuki Taniguchi
Agricultural Sciences (AS) , 2017, DOI: 10.4236/as.2017.89068
Abstract: This study evaluated the different expressions of cherry tomato growth, yield and quality under bamboo and rice husk biochar applications to soil. The experiment was conducted under glasshouse conditions at Hakozaki campus, Kyushu University, Japan and consisted of 5 treatments, namely 1) no biochar application as a control; 2) 2% (RH2) and 3) 5% (RH5) of rice husk biochar; 4) 2% (BB2) and 5) 5% (BB5) of bamboo biochar. Bamboo biochar application significantly improved tomato growth, including number of leaves, fresh biomass yield of aboveground and underground parts for BB5; number of fruit; fresh yield from 24% - 25% for BB2 and BB5. In particular, both bamboo and rice husk biochar application at two rates 2% and 5% had positive effects on tomato quality, demonstrated by the increased total sugar content from 56% to 91%, and the enhancement of ascorbic acid content for BB2 and RH2 by 12% and 17%, respectively. Those improvements reflected the soil physiochemical property changes after biochar application, including the increase in plant available water for bamboo biochar amendment before and after cultivating by 25% - 38% and 9% - 18%, respectively, compared with those of control; and the increased total soil N for bamboo biochar treatments (11% - 14%). Generally, all data above support bamboo biochar utilization for the purpose of improving soil properties and developing crop production.
Statistical Estimation for CAPM with Long-Memory Dependence
Tomoyuki Amano,Tsuyoshi Kato,Masanobu Taniguchi
Advances in Decision Sciences , 2012, DOI: 10.1155/2012/571034
Abstract: We investigate the Capital Asser Pricing Model (CAPM) with time dimension. By using time series analysis, we discuss the estimation of CAPM when market portfolio and the error process are long-memory process and correlated with each other. We give a sufficient condition for the return of assets in the CAPM to be short memory. In this setting, we propose a two-stage least squares estimator for the regression coefficient and derive the asymptotic distribution. Some numerical studies are given. They show an interesting feature of this model. 1. Introduction The CAPM is one of the typical models of risk asset’s price on equilibrium market and has been used for pricing individual stocks and portfolios. At first, Markowitz [1] did the groundwork of this model. In his research, he cast the investor’s portfolio selection problem in terms of expected return and variance. Sharpe [2] and Lintner [3] developed Markowitz’s idea for economical implication. Black [4] derived a more general version of the CAPM. In their version, the CAPM is constructed based on the excess of the return of the asset over zero-beta return , where and are the return of the th asset and the market portfolio and is the return of zero-beta portfolio of the market portfolio. Campbell et al. [5] discussed the estimation of CAPM, but in their work they did not discuss the time dimension. However, in the econometric analysis, it is necessary to investigate this model with the time dimension; that is, the model is represented as . Recently from the empirical analysis, it is known that the return of asset follows a short-memory process. But Granger [6] showed that the aggregation of short-memory processes yields long-memory dependence, and it is known that the return of the market portfolio follows a long-memory process. From this point of view, first, we show that the return of the market portfolio and the error process are long-memory dependent and correlated with each other. For the regression model, the most fundamental estimator is the ordinary least squares estimator. However, the dependence of the error process with the explanatory process makes this estimator to be inconsistent. To overcome this difficulty, the instrumental variable method is proposed by use of the instrumental variables which are uncorrelated with the error process and correlated with the explanatory variable. This method was first used by Wright [7], and many researchers developed this method (see Reiers?l [8], Geary [9], etc.). Comprehensive reviews are seen in White [10]. However, the instrumental variable method has
Optimal Portfolios with End-of-Period Target
Hiroshi Shiraishi,Hiroaki Ogata,Tomoyuki Amano,Valentin Patilea,David Veredas,Masanobu Taniguchi
Advances in Decision Sciences , 2012, DOI: 10.1155/2012/703465
Abstract: We study the estimation of optimal portfolios for a Reserve Fund with an end-of-period target and when the returns of the assets that constitute the Reserve Fund portfolio follow two specifications. In the first one, assets are split into short memory (bonds) and long memory (equity), and the optimality of the portfolio is based on maximizing the Sharpe ratio. In the second, returns follow a conditional heteroskedasticity autoregressive nonlinear model, and we study when the distribution of the innovation vector is heavy-tailed stable. For this specification, we consider appropriate estimation methods, which include bootstrap and empirical likelihood. 1. Introduction The Government Pension Investment Fund (GPIF) of Japan was established in April 1st 2006 as an independent administrative institution with the mission of managing and investing the Reserve Fund of the employees’ pension insurance and the national pension (http://www.gpif.go.jp/ for more information) [1]. It is the world’s largest pension fund ($1.4 trillions in assets under management as of December 2009), and it has a mission of managing and investing the Reserve Funds in safe and efficient investment with a long-term perspective. Business management targets to be achieved by GPIF are set by the Minister of Health, Labour, and Welfare based on the law on the general rules of independent administrative agencies. In the actuarial science, “required Reserve Fund” for pension insurance has been investigated for a long time. The traditional approach focuses on the expected value of future obligations and interest rate. Then, the investment strategy is determined for exceeding the expected value of interest rate. Recently, solvency for the insurer is defined in terms of random values of future obligations (e.g., Olivieri and Pitacco [2]). In this paper, we assume that the Reserve Fund is defined in terms of the random interest rate and the expected future obligations. Then, we propose optimal portfolios by optimizing the randomized Reserve Fund. The GPIF invests in a portfolio of domestic and international stocks and bonds. In this paper, we consider the optimal portfolio problem of the Reserve Fund under two econometric specifications for the asset’s returns. First, we select the optimal portfolio weights based on the maximization of the Sharpe ratio under three different functional forms for the portfolio mean and variance, two of them depending on the Reserve Fund at the end-of-period target (about 100 years). Following the asset structure of the GPIF, we split the assets into cash and
The Flavonoid Apigenin Downregulates CDK1 by Directly Targeting Ribosomal Protein S9
Yosuke Iizumi, Masakatsu Oishi, Tomoyuki Taniguchi, Wakana Goi, Yoshihiro Sowa, Toshiyuki Sakai
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0073219
Abstract: Flavonoids have been reported to inhibit tumor growth by causing cell cycle arrest. However, little is known about the direct targets of flavonoids in tumor growth inhibition. In the present study, we developed a novel method using magnetic FG beads to purify flavonoid-binding proteins, and identified ribosomal protein S9 (RPS9) as a binding partner of the flavonoid apigenin. Similar to treatment with apigenin, knockdown of RPS9 inhibited the growth of human colon cancer cells at the G2/M phase by downregulating cyclin-dependent kinase 1 (CDK1) expression at the promoter level. Furthermore, knockdown of RPS9 suppressed G2/M arrest caused by apigenin. These results suggest that apigenin induces G2/M arrest at least partially by directly binding and inhibiting RPS9 which enhances CDK1 expression. We therefore raise the possibility that identification of the direct targets of flavonoids may contribute to the discovery of novel molecular mechanisms governing tumor growth.
Apigenin Sensitizes Prostate Cancer Cells to Apo2L/TRAIL by Targeting Adenine Nucleotide Translocase-2
Masakatsu Oishi, Yosuke Iizumi, Tomoyuki Taniguchi, Wakana Goi, Tsuneharu Miki, Toshiyuki Sakai
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0055922
Abstract: Apo2 ligand (Apo2L)/tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a promising cancer therapeutic agent. Recombinant human Apo2L/TRAIL has been under clinical trials, whereas various kinds of malignant tumors have resistance to Apo2L/TRAIL. We and others have shown that several anticancer agents and flavonoids overcome resistance to Apo2L/TRAIL by upregulating death receptor 5 (DR5) in malignant tumor cells. However, the mechanisms by which these compounds induce DR5 expression remain unknown. Here we show that the dietary flavonoid apigenin binds and inhibits adenine nucleotide translocase-2 (ANT2), resulting in enhancement of Apo2L/TRAIL-induced apoptosis by upregulation of DR5. Apigenin and genistein, which are major flavonoids, enhanced Apo2L/TRAIL-induced apoptosis in cancer cells. Apigenin induced DR5 expression, but genistein did not. Using our method identifying the direct targets of flavonoids, we compared the binding proteins of apigenin with those of genistein. We discovered that ANT2 was a target of apigenin, but not genistein. Similarly to apigenin, knockdown of ANT2 enhanced Apo2L/TRAIL-induced apoptosis by upregulating DR5 expression at the post-transcriptional level. Moreover, silencing of ANT2 attenuated the enhancement of Apo2L/TRAIL-induced apoptosis by apigenin. These results suggest that apigenin upregulates DR5 and enhances Apo2L/TRAIL-induced apoptosis by binding and inhibiting ANT2. We propose that ANT2 inhibitors may contribute to Apo2L/TRAIL therapy.
On the Convergence of Observed Partial Likelihood under Incomplete Data with Two Class Possibilities  [PDF]
Tomoyuki Sugimoto
Open Journal of Statistics (OJS) , 2014, DOI: 10.4236/ojs.2014.42012
Abstract:

In this paper, we discuss the theoretical validity of the observed partial likelihood (OPL) constructed in a Coxtype model under incomplete data with two class possibilities, such as missing binary covariates, a cure-mixture model or doubly censored data. A main result is establishing the asymptotic convergence of the OPL. To reach this result, as it is difficult to apply some standard tools in the survival analysis, we develop tools for weak convergence based on partial-sum processes. The result of the asymptotic convergence shown here indicates that a suitable order of the number of Monte Carlo trials is less than the square of the sample size. In addition, using numerical examples, we investigate how the asymptotic properties discussed here behave in a finite sample.

The unexpected emotional similarities and behavioral differences of Japanese men experiencing parenthood in Japan and the USA  [PDF]
Hatsumi Taniguchi
Open Journal of Nursing (OJN) , 2012, DOI: 10.4236/ojn.2012.23031
Abstract: The purpose of this study was to understand the impact of childbirth and the experience of fatherhood on Japanese men in Japan and a foreign country. Descriptive phenomenology was used to study a total of 14 Japanese men who attended childbirth and experienced parenting in the United States and Japan. The Colaizzi method of data analysis was used to analyze responses to open-ended questions. Responses to these questions showed several similarities between the two groups of men. First, men in both countries felt closer to with their spouses having gone through the experience of childbirth together. Second, both groups nevertheless recognized a strong bond between mother and the baby, leading them to feel at times isolated. Third, both groups were concerned about their wives’ emotional swings during pregnancy and child rearing. Finally, both groups were more focused on their wives and babies than themselves. There were also several interesting differences. Japanese men who were living in Hawaii were more involved in taking care of their children and in helping with household chores than those living in Japan. This was due to living in a more family-oriented society, as well as a result of limited support from their extended families back in Japan. A result of spending more time with their wives and babies was that Japanese men in the United States understood more fully the stress of childcare. On the other hand, due to Japan’s work-oriented society, men in Japan relied more on support from their extended families, leaving them less time with their wives and children. This study clearly shows that social support systems alter gender roles and behavior, leading to significant differences in the experience of parenthood in Japan and a foreign country.
The Impact of Liberalization on the Production of Electricity in Japan: Stochastic Frontier Analysis  [PDF]
Miyuki Taniguchi
Open Journal of Applied Sciences (OJAppS) , 2014, DOI: 10.4236/ojapps.2014.44016
Abstract: This study aims to measure the impact of liberalization on the efficiency of electricity production in Japan using Stochastic Frontier Analysis (SFA). In addition, this study also aims to examine whether or not economies of scale exist in the electricity generation sector and the transmission sector, and whether or not economies of scope exist between electricity generation and transmission. Since 1995, liberalization of the electricity market in Japan has been phased in and regulations on entry have been relaxed three times. One motivation for these regularity changes has been to improve the efficiency of electricity production by introducing competition. Using a panel data set on the nine main power companies in Japan over the period 1970-2010, estimates of fixed-effects and stochastic frontier models of the cost function are obtained and compared. Estimates of the cost function show that liberalization has improved cost efficiency when both frontier models and non-frontier models are estimated. Estimates of the fixed-effects model are used to calculate economies of scale and economies scope because the data support the fixed-effects model. Economies of scope are found to exist for all nine power companies, while overall economies of scope declined in the 1970s and have improved little by little since the 1980s.
Super Characteristic Classes and Riemann-Roch Type Formula  [PDF]
Tadashi Taniguchi
Advances in Pure Mathematics (APM) , 2015, DOI: 10.4236/apm.2015.56034
Abstract:

The main purpose of this article is to define the super characteristic classes on a super vector bundle over a superspace. As an application, we propose the examples of Riemann-Roch type formula. We also introduce the helicity group and cohomology with respect to coefficient of the helicity group. As an application, we propose the examples of Gauss-Bonnet type formula.

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