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Search Results: 1 - 10 of 351 matches for " Yumiko Komori "
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Spherical functions on the space of $p$-adic unitary hermitian matrices
Yumiko Hironaka,Yasushi Komori
Mathematics , 2012,
Abstract: We investigate the space $X$ of unitary hermitian matrices over $\frp$-adic fields through spherical functions. First we consider Cartan decomposition of $X$, and give precise representatives for fields with odd residual characteristic, i.e., $2\notin \frp$. In the latter half we assume odd residual characteristic, and give explicit formulas of typical spherical functions on $X$, where Hall-Littlewood symmetric polynomials of type $C_n$ appear as a main term, parametrization of all the spherical functions. By spherical Fourier transform, we show the Schwartz space $\SKX$ is a free Hecke algebra $\hec$-module of rank $2^n$, where $2n$ is the size of matrices in $X$, and give the explicit Plancherel formula on $\SKX$.
Spherical functions on the space of $p$-adic unitary hermitian matrices II, the case of odd size
Yumiko Hironaka,Yasushi Komori
Mathematics , 2014,
Abstract: We are interested in the harmonic analysis on $p$-adic homogeneous spaces based on spherical functions. In the present paper, we investigate the space $X$ of unitary hermitian matrices of odd size over a ${\mathfrak p}$-adic field of odd residual characteristic, which is a continuation of our previous paper where we have studied for even size matrices. First we give the explicit representatives of the Cartan decomposition of $X$ and introduce a typical spherical function $\omega(x;z)$ on $X$. After studying the functional equations, we give an explicit formula for $\omega(x;z)$, where Hall-Littlewood polynomials of type $C_n$ appear as a main term, though the unitary group acting on $X$ is of type $BC_n$. By spherical transform, we show the Schwartz space ${\mathcal S}(K \backslash X)$ is a free Hecke algebra ${\mathcal H}(G, K)$-module of rank $2^n$, where $2n+1$ is the size of matrices in $X$, and give parametrization of all the spherical functions on $X$ and the explicit Plancherel formula on ${\mathcal S}(K \backslash X)$.
Isolation and Biochemical Characterization of Rubelase, a Non-Hemorrhagic Elastase from Crotalus ruber ruber (Red Rattlesnake) Venom
Yumiko Komori,Kaname Sakai,Katsuyoshi Masuda,Toshiaki Nikai
Toxins , 2011, DOI: 10.3390/toxins3070900
Abstract: A novel non-hemorrhagic basic metalloprotease, rubelase, was isolated from the venom of Crotalus ruber ruber. Rubelase hydrolyzes succinyl-L-alanyl-L-alanyl-L-alanyl p-nitroanilide (STANA), a specific substrate for elastase, and the hydrolytic activity was inhibited by chelating agents. It also hydrolyzes collagen and fibrinogen. However, hemorrhagic activity was not observed. By ESI/Q-TOF and MALDI/TOF mass spectrometry combined with Edman sequencing procedure, the molecular mass of rubelase was determined to be 23,266 Da. Although its primary structure was similar to rubelysin (HT-2), a hemorrhagic metalloprotease isolated from the same snake venom, the circumstances surrounding putative zinc binding domain HEXXHXXGXXH were found to be different when the three-dimensional computer models of both metalloproteases were compared. The cytotoxic effects of rubelase and rubelysin on cultured endothelial and smooth muscle cells were also different, indicating that the substitution of several amino acid residues causes the changes of active-site conformation and cell preference.
Comparison of Sea Snake (Hydrophiidae) Neurotoxin to Cobra (Naja) Neurotoxin
Yumiko Komori,Masaya Nagamizu,Kei-ichi Uchiya,Toshiaki Nikai,Anthony T. Tu
Toxins , 2009, DOI: 10.3390/toxins1020151
Abstract: Both sea snakes and cobras have venoms containing postsynaptic neurotoxins. Comparison of the primary structures indicates many similarities, especially the positions of the four disulfide bonds. However, detailed examination reveals differences in several amino acid residues. Amino acid sequences of sea snake neurotoxins were determined, and then compared to cobra neurotoxins by computer modeling. This allowed for easy comparison of the similarities and differences between the two types of postsynaptic neurotoxins. Comparison of computer models for the toxins of sea snakes and cobra will reveal the three dimensional difference of the toxins much clearer than the amino acid sequence alone.
Biological and Pathological Studies of Rosmarinic Acid as an Inhibitor of Hemorrhagic Trimeresurus flavoviridis (habu) Venom
Hnin Thanda Aung,Toshiaki Nikai,Yumiko Komori,Tsunemasa Nonogaki,Masatake Niwa,Yoshiaki Takaya
Toxins , 2010, DOI: 10.3390/toxins2102478
Abstract: In our previous report, rosmarinic acid (RA) was revealed to be an antidote active compound in Argusia argentea (family: Boraginaceae). The plant is locally used in Okinawa in Japan as an antidote for poisoning from snake venom, Trimeresurus flavoviridis (habu). This article presents mechanistic evidence of RA’s neutralization of the hemorrhagic effects of snake venom. Anti-hemorrhagic activity was assayed by using several kinds of snake venom. Inhibition against fibrinogen hydrolytic and collagen hydrolytic activities of T. flavoviridis venom were examined by SDS-PAGE. A histopathological study was done by microscopy after administration of venom in the presence or absence of RA. RA was found to markedly neutralize venom-induced hemorrhage, fibrinogenolysis, cytotoxicity and digestion of type IV collagen activity. Moreover, RA inhibited both hemorrhage and neutrophil infiltrations caused by T.?flavoviridis venom in pathology sections. These results demonstrate that RA inhibited most of the hemorrhage effects of venom. These findings indicate that rosmarinic acid can be expected to provide therapeutic benefits in neutralization of snake venom accompanied by heat stability.
Isolation and Chemical Characterization of a Toxin Isolated from the Venom of the Sea Snake, Hydrophis torquatus aagardi
Masaya Nagamizu,Yumiko Komori,Kei-ichi Uchiya,Toshiaki Nikai,Anthony T. Tu
Toxins , 2009, DOI: 10.3390/toxins1020162
Abstract: Sea snakes (family: Hydrophiidae) are serpents found in the coastal areas of the Indian and Pacific Oceans. There are two subfamilies in Hydrophiidae: Hydrophiinae and Laticaudinae. A toxin, aagardi toxin, was isolated from the venom of the Hydrophiinae snake, Hydrophis torquatus aagardi and its chemical properties such as molecular weight, isoelectric point, importance of disulfide bonds, lack of enzymatic activity and amino acid sequence were determined. The amino acid sequence indicated a close relationship to the primary structure of other Hydrophiinae toxins and a significant difference from Laticaudinae toxins, confirming that primary toxin structure is closely related to sea snake phylogenecity.
The Acquisition of Complex Structures: The Case of Child ESL  [PDF]
Yumiko Yamaguchi
Open Journal of Modern Linguistics (OJML) , 2013, DOI: 10.4236/ojml.2013.33030

This study examines how complex linguistic structures are acquired in child English as a second language. The spontaneous speech producing by a Japanese primary school child, learning English in a naturalistic environment, was audio-recorded regularly over two years and the development of complex syntactic structures containing subordinate clauses was compared with the acquisition of other English morphosyntactic structures as represented within Processability Theory (PT) (Pienemann, 1998; Pienemann, Di Biase, & Kawaguchi, 2005). Although PT predicts that subordination is acquired at the highest stage in processability hierarchy, the results in this longitudinal study show that some of the subordinate constructions emerge at earlier stages in child ESL acquisition.

Seasonal Mood and Behavioral Changes for Japanese Residents in the United Kingdom  [PDF]
Yumiko Kurata, Shinobu Nomura
Psychology (PSYCH) , 2012, DOI: 10.4236/psych.2012.329128
Abstract: The aim of this study was to investigate seasonal changes in mood and behavior for Japanese residents in UK A questionnaire survey was conducted with Japanese residents in the UK (n = 100) who participated both a combination winter and summer research. First, a longitudinal study comparing two surveys—one in summer and another in winter—was carried out to determine how the level of seasonal changes influenced depression among Japanese living in the UK. Then, we examined seasonal changes in mood and behavior over a 12-month period based on the degree of seasonal dependence. Paired t-tests on Global Seasonality Score (GSS score) and the Center for Epidemiologic Studies Depression Scale (CES-D) scores by winter and summer demonstrated that each score had a significant seasonal difference; individual scores were higher in winter than in summer. We examined the difference between high seasonality group, medium seasonal group, and non-seasonal group, regarding to the winter CES-D and summer CES-D scores. The ANOVA revealed a significant difference on the winter score (Winter: F(2,97) = 4.62, p < .01, Summer: F(2,97) = 3.24, p < .05). Although we did not find any interaction between seasonal change and season, the main effect was significant for season. The results showed fluctuations in which mood, social activity, and sleep all declined during the winter and then improved during the summer. It indicated that depressive symptoms among Japanese living in the UK fluctuate due to seasonality; over a period of 12 months, their mood and behavior declined during winter and improved during summer. As described, Japanese living in the UK experience environmental changes due to seasonality. This suggests that the environmental factor called seasonal change can partly explain why Japanese living in the UK suffer from mental and physical disorders. Mental health measures specific to the local environment are necessary to support individuals to adapt to and live under an environment different from home country.
Spitzer IRAC Colors of Nebulae Associated with Star-Forming Regions  [PDF]
Yoichi Itoh, Yumiko Oasa
International Journal of Astronomy and Astrophysics (IJAA) , 2019, DOI: 10.4236/ijaa.2019.91004
Abstract: Star-forming regions are often associated with nebulosity. In this study, we investigated infrared diffuse emission in Spitzer IRAC images. The infrared nebula L1527 traces outflows emanating from a low-mass protostar. The nebular color is consistent with the color of a stellar photosphere with large extinction. Nebulae around the HII region W5-East are bright in the infrared. These colors are consistent with the model color of dust containing polycyclic aromatic hydrocarbon (PAH). The strength of ultraviolet irradiation of the nebulae and the small dust fraction were deduced from the infrared colors of the nebulae. We found that the edges of the nebulae are irradiated by strong ultraviolet radiation and have abundant small dust. Dust at the surface of the molecular cloud is thought to be destroyed by ultraviolet radiation from an early-type star.
Regulation of bone mass at unloaded condition by osteocyte network
Toshihisa Komori
Arthritis Research & Therapy , 2012, DOI: 10.1186/ar3568
Abstract: We searched for the molecules responsible for disuse osteoporosis using BCL2 transgenic mice. Pyruvate dehydrogenase kinase isozymes (Pdk1, Pdk2, Pdk3, and Pdk4) are negative regulators of pyruvate dehydrogenase complex (PDC), which converts pyruvate to acetyl-CoA in the mitochondria, linking glycolysis to the energetic and anabolic functions of the tricarboxylic acid (TCA) cycle. Pdk4 was upregulated in femurs and tibiae of wild-type mice but not of BCL2 transgenic mice after tail suspension. Bone in Pdk4-/- mice developed normally and was maintained. At unloading, however, bone mass was reduced due to enhanced osteoclastogenesis and Rankl expression in wild-type mice but not in Pdk4-/- mice. Osteoclast differentiation of Pdk4-/- bone marrow-derived monocyte/macrophage lineage cells (BMMs) in the presence of M-CSF and RANKL was suppressed, and osteoclastogenesis was impaired in the coculture of wild-type BMMs and Pdk4-/- osteoblasts, in which Rankl expression and promoter activity were reduced. Further, introduction of Pdk4 into Pdk4-/- BMMs and osteoblasts enhanced osteoclastogenesis and Rankl expression and activated Rankl promoter. These findings indicate that upregulation of Pdk4 expression in osteoblasts and bone marrow cells after unloading is, at least in part, responsible for the enhancement of osteoclastogenesis and bone resorption after unloading [1].
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