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Search Results: 1 - 10 of 146 matches for " Tasuku Mitani "
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Perspective of Adaptive CN System for Forecasting Congestion of Road Traffic Flow  [PDF]
Tasuku Takagi
Communications and Network (CN) , 2014, DOI: 10.4236/cn.2014.62008
Abstract:

Basing upon the Weber-Fechner Law with respect to the stimulus (distance-headway) to the vehicle driver and the driver’s sensation (speed), the characteristic speed Vβ is defined, which is the critical vehicles flow speed just before going to congestion in road traffic flow. From the information of real time measurement of traffic flow speed (V) and time-headway (T) at the specific positions along the road, the value of Vβ is calculated and used for forecasting the flow. Discussed is how to use each Vβ to forecast the congestion. The CN system devoted to the management of road traffic flow is proposed. The idea may contribute not only to easing the traffic flow but also to optimizing it to get high efficient traffic flow.

GSE Is a Maternal Factor Involved in Active DNA Demethylation in Zygotes
Yuki Hatanaka, Natsumi Shimizu, Satoshi Nishikawa, Mikiko Tokoro, Seung-Wook Shin, Takuji Nishihara, Tomoko Amano, Masayuki Anzai, Hiromi Kato, Tasuku Mitani, Yoshihiko Hosoi, Satoshi Kishigami, Kazuya Matsumoto
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0060205
Abstract: After fertilization, the sperm and oocyte genomes undergo extensive epigenetic reprogramming to form a totipotent zygote. The dynamic epigenetic changes during early embryo development primarily involve DNA methylation and demethylation. We have previously identified Gse (gonad-specific expression gene) to be expressed specifically in germ cells and early embryos. Its encoded protein GSE is predominantly localized in the nuclei of cells from the zygote to blastocyst stages, suggesting possible roles in the epigenetic changes occurring during early embryo development. Here, we report the involvement of GSE in epigenetic reprogramming of the paternal genome during mouse zygote development. Preferential binding of GSE to the paternal chromatin was observed from pronuclear stage 2 (PN2) onward. A knockdown of GSE by antisense RNA in oocytes produced no apparent effect on the first and second cell cycles in preimplantation embryos, but caused a significant reduction in the loss of 5-methylcytosine (5 mC) and the accumulation of 5-hydroxymethylcytosine (5 hmC) in the paternal pronucleus. Furthermore, DNA methylation levels in CpG sites of LINE1 transposable elements, Lemd1, Nanog and the upstream regulatory region of the Oct4 (also known as Pou5f1) gene were clearly increased in GSE-knockdown zygotes at mid-pronuclear stages (PN3-4), but the imprinted H19-differential methylated region was not affected. Importantly, DNA immunoprecipitation of 5 mC and 5 hmC also indicates that knockdown of GSE in zygotes resulted in a significant reduction of the conversion of 5 mC to 5 hmC on LINE1. Therefore, our results suggest an important role of maternal GSE for mediating active DNA demethylation in the zygote.
A Study of Pansharpened Images Based on the HSI Transformation Approach  [PDF]
Yoshihiro Mitani, Yoshihiko Hamamoto
Journal of Software Engineering and Applications (JSEA) , 2012, DOI: 10.4236/jsea.2012.512B031
Abstract: A pan-sharpen technique artificially produces a high-resolution image by image fusion techniques using high-resolution panchromatic and low-resolution multispectral images. Thus, the appearance of the color image can improve. In this paper, the effectiveness of three pan-sharpening methods based on the HSI transform approach is investigated. Three models are the hexcone, double hexcones, and Haydn’s approach. Furthermore, the effect of smoothing the low-resolution multispectral image is also investigated. The smoothing techniques are the Gaussian filter and the bilateral filter. The experimental results show that Haydn’s model is superior to others. The effectiveness of smoothing the low-resolution multispectral image is also shown.
Hideo Mitani
Hideo Mitani
Revista Dental Press de Ortodontia e Ortopedia Facial , 2009, DOI: 10.1590/s1415-54192009000300004
Abstract:
Fibroblast Growth Factor 23 (FGF23) and Disorders of Phosphate Metabolism
Tasuku Saito, Seiji Fukumoto
International Journal of Pediatric Endocrinology , 2009, DOI: 10.1155/2009/496514
Abstract: It is well known that serum calcium (Ca) level is regulated within a narrow range by actions of two calcium-regulating hormones, parathyroid hormone (PTH) and 1,25-dihydroxyvitamin D [1,25(OH)2D]. In contrast, while derangements in serum phosphate level result in rickets/osteomalacia or ectopic calcification, the regulatory mechanisms of serum phosphate have been largely unknown. Because PTH and 1,25(OH)2D can affect serum phosphate level, it has been unclear whether there is a tight mechanism of serum phosphate level regulated by a specific phosphate-regulating hormone. However, the identification of fibroblast growth factor 23 (FGF23) and subsequent studies certainly changed this view. FGF23 works as a phosphate-regulating hormone and aberrant functions of FGF23 result in several diseases. Here, we briefly review the physiological and pathophysiological roles of FGF23.FGF family members are now defined as humoral factors which have FGF homology region characterized by -trefoil structure. FGF23 was identified as the last member of FGF family [1] and belongs to the FGF19 subfamily as well as FGF19 and FGF21 [2]. FGF23 is produced as a peptide with 251 amino acids by bone [3, 4]. There is a signal peptide with 24 amino acids, and the secreted FGF23 protein consists of 227 amino acids which is approximately 32-kD [5]. A part of FGF23 protein is proteolytically cleaved between 179Arg and 180Ser into inactive fragments by enzymes that recognize 176R-177X-178X-179R motif just before the processing site (Figure 1). FGF homology region is present in the N-terminal portion of this processing site of FGF23.It has been shown that FGF23 suppresses the expression of type 2a and 2c sodium-phosphate cotransporters in the brush border membrane of proximal tubules which mediate physiological phosphate reabsorption. In addition, FGF23 reduces serum 1,25(OH)2D level by suppressing the expression of 25-hydroxyvitamin D [25(OH)D]--hydroxylase and also enhancing the expression of 25(OH)
Multi-Objective Robust Parameter Design Methodology Applied to Microwave Circuit
Takafumi Nakagawa,Tasuku Kirikoshi
Lecture Notes in Engineering and Computer Science , 2012,
Abstract:
Robust Parameter Design Methodology for Microwave Circuits Considering the Manufacturing Variations
Takafumi Nakagawa,Tasuku Kirikoshi
IAENG International Journal of Computer Science , 2012,
Abstract:
Fibroblast Growth Factor 23 (FGF23) and Disorders of Phosphate Metabolism
Saito Tasuku,Fukumoto Seiji
International Journal of Pediatric Endocrinology , 2009, DOI: 10.1186/1687-9856-2009-496514
Abstract: Derangements in serum phosphate level result in rickets/osteomalacia or ectopic calcification indicating that healthy people without these abnormalities maintain serum phosphate within certain ranges. These results indicate that there must be a regulatory mechanism of serum phosphate level. Fibroblast growth factor 23 (FGF23) was identified as the last member of FGF family. FGF23 is produced by bone and reduces serum phosphate level by suppressing phosphate reabsorption in proximal tubules and intestinal phosphate absorption through lowering 1,25-dihydroxyvitamin D level. It has been shown that excess and deficient actions of FGF23 result in hypophosphatemic rickets/osteomalacia and hyperphosphatemic tumoral calcinosis, respectively. These results indicate that FGF23 works as a hormone, and several disorders of phosphate metabolism can be viewed as endocrine diseases. It may become possible to treat patients with abnormal phosphate metabolism by pharmacologically modifying the activity of FGF23.
Maximizing Submodular Functions with the Diminishing Return Property over the Integer Lattice
Tasuku Soma,Yuichi Yoshida
Computer Science , 2015,
Abstract: The problem of maximizing non-negative monotone submodular functions under a certain constraint has been intensively studied in the last decade. In this paper, we address the problem for functions defined over the integer lattice. Suppose that a non-negative monotone submodular function $f:\mathbb{Z}_+^n \to \mathbb{R}_+$ is given via an evaluation oracle. Furthermore, we assume that $f$ satisfies the diminishing return property, which is not an immediate consequence of the submodularity when the domain is the integer lattice. Then, we show (i) a $(1-1/e-\epsilon)$-approximation algorithm for a cardinality constraint with $\widetilde{O}(\frac{n}{\epsilon}\log \frac{r}{\epsilon})$ queries, where $r$ is the maximum cardinality of feasible solutions, (ii) a $(1-1/e-\epsilon)$-approximation algorithm for a polymatroid constraint with $\widetilde{O}(\frac{nr}{\epsilon^4}+n^6)$ queries, where $r$ is the rank of the polymatroid, and (iii) a $(1-1/e-\epsilon)$-approximation algorithm for a knapsack constraint with $\widetilde{O}(\frac{n^2}{\epsilon^{18}}\log \frac{1}{w})(\frac{1}{\epsilon})^{O(1/\epsilon^8)}$ queries, where $w$ is the minumum weight of elements. Our algorithms for polymatroid constraints and knapsack constraints first extend the domain of the objective function to the Euclidean space and then run the continuous greedy algorithm. We give two different kinds of continuous extensions, one is for knapsack constraints and the other is for polymatroid constraints, which might be of independent interest.
A B3LYP study on electronic structures of [(X)mMn(μ-oxo)2Mn(Y)n]q+ (X, Y = H2O, OH and O) as a Mn cluster model of OEC  [PDF]
Masashi Katsuda, Masaki Mitani, Yasunori Yoshioka
Journal of Biophysical Chemistry (JBPC) , 2012, DOI: 10.4236/jbpc.2012.32013
Abstract: Electronic and molecular structures of [(X)mMn(μ-oxo)2Mn(Y)n]q+ (X, Y = H2O, OH and O), which are Mn cluster models at catalytic sites of OEC, were studied by broken-symmetry unrestricted B3LYP method. Two paths from the S0 to S3 states of Kok cycle were investigated. One is a path starting from [Mn(II) (μ-oxo)2Mn(III)] at the S0 state, and another is from [Mn(III) (μ-oxo)2Mn(III)] at the S0. Results found in this study are summarized as, 1) In [Mn(II), Mn(III)], it is not possible that H2O molecules coordinate to the Mn atoms with retaining the octahedral configuration. 2) The OHˉ anion selectively coordinates to Mn(IV) rather than Mn(III). 3) When the oxo atom directly bind to the Mn atom, the Mn atom must be a Mn(IV). From these results, the catalytic mechanism for four-electron oxidation of two H2O molecules in OEC is proposed. 1) The Mn4(II, III, IV, IV) at S0 is ruled out. 2) For Mn4(III, III, IV, IV) at S1, the Mn atom coordinated by OHˉ anion is a Mn(IV) not Mn(III). 3) Only Mn(III) ion which is coordinated by a H2O molecule at S0 plays crucial roles for the oxidation.
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