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Search Results: 1 - 10 of 2939 matches for " Masayuki Aoki "
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A Pediatric Case of Systemic Lupus Erythematosus Developed 10 Years after Cord Blood Transplantation for Juvenile Myelomonocytic Leukemia
Masayuki Nagasawa,Yuki Aoki
Case Reports in Transplantation , 2012, DOI: 10.1155/2012/619126
A Pediatric Case of Systemic Lupus Erythematosus Developed 10 Years after Cord Blood Transplantation for Juvenile Myelomonocytic Leukemia
Masayuki Nagasawa,Yuki Aoki
Case Reports in Transplantation , 2012, DOI: 10.1155/2012/619126
Abstract: Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a most powerful immunotherapy for hematological malignancies. However, the impact of immunological disturbances as a result of allo-HSCT is not understood well. We experienced an 11-year-old boy who presented with systemic lupus erythemathosus (SLE) 10 years after unrelated cord blood transplantation of male origin for juvenile myelomonocytic leukemia (JMML) with monosomy 7. Bone marrow examination showed complete remission without monosomy 7. Genetic analysis of peripheral blood revealed mixed chimera with recipient cells consisting of <5% of T cells, 50–60% of B cells, 60–75% of NK cells, 70–80% of macrophages, and 50–60% of granulocytes. Significance of persistent mixed chimera as a cause of SLE is discussed. 1. Introduction Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is an effective treatment to cure the hematological malignancy through the alloimmune reaction. However, excessive alloimmune reaction triggers acute graft versus host disease (aGVHD) and it attacks various organs and induces their dysfunction, which is often life-threatening. Chronic GVHD is based on more insidious alloimmune reaction and its clinical symptoms sometimes mimic autoimmune diseases. In allo-HSCT, donor cells usually replace the bone marrow cells completely, which is called complete chimera. Donor and recipient hematopoietic cells sometimes coexist stably, which is called mixed chimera. Although mixed chimera is a sign of relapse of hematological malignancy, there are cases of stable and persistent chimera without relapse. However, the impact of immunological disturbances as a result of allo-HSCT and mixed chimera is not understood well. We had an 11-year-old boy who presented with SLE 10 years after allogeneic cord blood transplantation. Interestingly, most of T cells were of donor origin, but B cells, NK cells, macrophages, and granulocytes were mixed chimera. 2. Case Report At 6-month-old, he presented with hepatosplenomegaly and skin eruption. Bone marrow examination revealed monosomy 7 and he was diagnosed as juvenile myelomonocytic leukemia through clinical evaluation. At 15-month-old, he received HLA-DRB1 one locus mismatched male-derived cord blood transplantation. Conditioning regimen was myeloablative (busulfan (140?mg/m2??× 4) + etoposide (15?mg?/kg/day × 4) + cyclophosphamide (60?mg/kg × 2) + antithymocyte globulin (2.5?mg/kg × 4)). GVHD prophylaxis was cyclosporine and short-term methotrexate. SCT was successful with only mild GVHD. Complete chimera was determined on day 41.
Audio-Visual Biofeedback for Respiratory Motion Management: Comparison of the Reproducibility of Breath-Holding between Visual and Audio Guidance  [PDF]
Naoki Sano, Masahide Saito, Hiroshi Onishi, Kengo Kuriyama, Takafumi Komiyama, Kan Marino, Shinichi Aoki, Masayuki Araya
Journal of Modern Physics (JMP) , 2018, DOI: 10.4236/jmp.2018.913144
Abstract: Purpose: To compare the reproducibility of breath-holding and comfort between two biofeedback guidance methods (audio and visual) in a respiratory monitoring system. Method and Materials: An audio-feedback respiratory monitoring device, which was modified from a visual-feedback self-respiration monitoring system (Abches, APEX Medical Inc., Tokyo, Japan) previously developed by the authors’ group, was constructed. Twenty patients (13 men, 7 women; mean age, 68.5 years; range, 54 - 85 years) with tumors in the thorax or abdominal region were enrolled in the present study. Computed tomography images were acquired from all patients three times using the two (i.e., audio and visual) respiration monitoring devices. To evaluate the reproducibility of breath-holding, the distance between an anatomical landmark and the tumor position was measured. Furthermore, patients were asked which guidance method they preferred (visual or audio) for comfortable breath-holding. Results: The two guidance methods improved the reproducibility of breath-holding compared with free-breathing, and no significant overall differences between two methods were observed (the mean displacements of the landmark-tumor distance were 2.60 ± 1.38 mm and 2.35 ± 1.63 mm, for visual and audio guidance, respectively). In five patients, the magnitude of position displacement in the series of three computed tomography images under audio guidance was twice as large as the other under visual guidance. Audio guidance was preferred to visual guidance by 65% (13 of 20) of the patients. However, the reproducibility of breath-holding did not always correspond with patient preference. Conclusion: There were some individual differences in the reproducibility of the visual and audio guidance methods. More appropriate, individualized guidance methods for each patient would improve the reproducibility of breath-holding in respiratory motion management.
Prognostic Significance of Hematologic Markers in Patients with Head and Neck Squamous Cell Carcinomas  [PDF]
Ryohei Oya, Yukinori Takenaka, Kengo Aoki, Hiroko Hamaguchi, Kazuya Takemura, Masayuki Nozawa, Takahiro Kitamura, Yoshifumi Yamamoto, Atsuhiko Uno
International Journal of Otolaryngology and Head & Neck Surgery (IJOHNS) , 2018, DOI: 10.4236/ijohns.2018.72008
Abstract: Aim: To assess the prognostic value of hematologic markers for cancers of the head and neck region, according to tumor site. Methods: We reviewed the data of 441 patients diagnosed with head and neck squamous cell carcinomas (HNSCC) between 2006 and 2014. Overall survival rates were estimated using the Kaplan-Meier method and Cox proportional hazards models were used to assess the hazard ratio (HR) for death, according to hematologic markers. Results: In the univariate analyses, hemoglobin concentration; leukocyte, neutrophil, monocyte, and platelet counts; and the platelet-lymphocyte ratio were associated with overall survival. In the multivariate analyses, hemoglobin concentration (HR 0.55, 95% confidence interval [CI] 0.38 - 0.78, p < 0.001) and leukocyte (HR 1.57, 95% CI 1.11 - 2.23, p = 0.010), monocyte (HR 1.86, 95% CI 1.25 - 2.73, p = 0.003), and platelet (HR 2.17, 95% CI 1.24 - 3.57, p = 0.008) counts were independent prognostic factors for HNSCC. None of the hematologic markers were significant prognosticators for oral cancer. Leukocyte (HR 2.67, 95% CI 1.17 - 6.58, p = 0.018), monocyte (HR 4.04, 95%CI 1.85 - 8.56, p < 0.001), and platelet (HR 3.77, 95% CI 1.55 - 8.28, p = 0.005) counts were independent prognostic factors for laryngeal cancer. Conclusions: Several hematologic markers have prognostic significance for patients with HNSCC, however, the magnitude of the effect depends on the tumor site.
Factors Associated with Excessive Daytime Sleepiness in Obstructive Sleep Apnea Syndrome under CPAP Treatment  [PDF]
Wataru Yamadera, Shintaro Chiba, Masayuki Iwashita, Ryo Aoki, Daisuke Harada, Miki Sato, Hiroto Moriwaki, Keita Obuchi, Motohiro Ozone, Seiji Nishino, Hiroshi Itoh, Kazuhiko Nakayama
International Journal of Clinical Medicine (IJCM) , 2012, DOI: 10.4236/ijcm.2012.33039
Abstract: The purpose of this study was to assess factors associated with subjective sleep evaluation, chiefly excessive daytime sleepiness (EDS) in obstructive sleep apnea syndrome (OSAS) adult outpatients under continuous positive airway pressure (CPAP) treatment. One thousand and forty-eight OSAS outpatients (mean age: 51.4% male: 90.5%) who were treated by CPAP were consecutively collected. Age, sex, CPAP compliance (CPAP usage as their device of nights with application-time of at least 4 hours per night objectively; %usage ≥ 4 h/d), and Japanese version of the Pittsburgh Sleep Quality Index (PSQI-J) of the patients showing EDS (Japanese version of the Epworth Sleepiness Scale; JESS ≥ 11) were compared cross-sectionally with those of the patients who did not show EDS (JESS < 11). Nineteen point two % of all patients showed EDS subjectively. Two hundred one patients were classified to an EDS(+) group and an 847 patients were classified to EDS(–) group. Age and global PSQI-J scores were significantly different between the two groups. Logistic regression showed that EDS was significantly associated with global PSQI-J scores, but not with age. Among PSQI-J components, overall sleep quality, duration of sleep, sleep disturbance, and day dysfunction due to sleepiness were significantly higher in the EDS(+) group. Especially, 19.4% of patient in the EDS(+) group reported actual sleep time during the past month to be less than 5 hours/day. Although functional relationship should be further evaluated, insufficient sleep is the main factor associated with EDS in the OSAS patients under CPAP treatment.
s-Process Nucleosynthesis in Low-Metallicity Stars
Nobuyuki Iwamoto,Toshitaka Kajino,Grant J. Mathews,Masayuki Y. Fujimoto,Wako Aoki
Physics , 2002,
Abstract: We have made a parametric study of s-process nucleosynthesis in the metal poor ([Fe/H]=-2.7) stars LP625-44 and LP706-7. We find that a high neutron exposure and a small overlap factor are necessary to fit the abundance pattern observed in these two metal-deficient stars, particularly the abundance ratios, Pb/Ba $\approx 1$ and Ba/Sr $\approx 10$. We have also constructed stellar models to better understand how such s-process conditions could arise. We have calculated a 2$M_\odot$ model star with metallicity [Fe/H]=-2.7 from the ZAMS up to AGB phase. We find that for such low-metallicity stars the He convective shell reaches the bottom of the overlying H-rich envelope at the second thermal pulse. Protons are then carried into the hotter He burning layers and $^{13}$C is formed as protons mix into the He shell. Subsequently, material in the H-flash driven convective zone experiences a high neutron exposure due to the $^{13}$C($\alpha$, n) reaction. This results in a new neutron-capture s-process paradigm in which the abundances are characterized by only one neutron exposure. We suggest that this new s-process site may be a significant contributor to the s-process abundances in low-metallicity ([Fe/H] $\le -2.5$) stars.
The Stellar Abundances for Galactic Archaeology (SAGA) Database III - Analysis of Enrichment Histories for Elements and Two Modes of Star Formation during the Early Evolution of Milky Way
Shimako Yamada,Takuma Suda,Yutaka Komiya,Wako Aoki,Masayuki Y. Fujimoto
Physics , 2013, DOI: 10.1093/mnras/stt1652
Abstract: We study the enrichment histories for nine elements, C, four alpha-elements of Mg, Si, Ca, and Ti, Sc, and three iron-peak elements of Co, Ni, and Zn, by using a large number of stellar data, collected by the Stellar Abundances for Galactic Archaeology (SAGA) database. We find statistically significant changes, or breaks, of the mean abundance ratios to iron at three metallicities of [Fe/H]-1.8, -2.2, and -3.3. Across the first one, the mean abundance ratios decrease with the metallicity by similar extents for all the elements with the sufficient data. Across the latter two, downward trends with the metallicity are also detected but for limited elements, C, Co, Zn, and possibly Sc, and for two of Co and Zn, respectively. The breaks define four stellar populations with the different abundance patters which are dominant in each metallicity range divided by the breaks, Pop IIa, IIb, IIc, and IId in order of increasing metallicity. We also explore their spatial distributions with the spectroscopic distances to demonstrate that Pops IIa and IIb spread over the Galactic halo while Pops IIc and IId are observed near the Galactic plane. In particular, Pop IIc stars emerge around [Fe/H] -2.6 and coexist with Pop IIb stars, segregated by the spatial distributions. Our results reveal two distinct modes of star formation during the early stages of Galaxy formation, which are associated with the variations of IMF and the spatial distribution of remnant low-mass stars. For the two lower-metallicity populations, the enhancements of Zn and Co indicate a high-mass and top-heavy IMF together with the statistics on the carbon-enhanced stars. We discuss the relevance to the kinematically resolved structures of the Galactic halo and the possible sites of these populations within the framework of hierarchical structure formation scenario.
The Stellar Abundances for Galactic Archaeology (SAGA) Database II - Implications for Mixing and Nucleosynthesis in Extremely Metal-Poor Stars and Chemical Enrichment of the Galaxy
Takuma Suda,Shimako Yamada,Yutaka Katsuta,Yutaka Komiya,Chikako Ishizuka,Wako Aoki,Masayuki Y. Fujimoto
Physics , 2010, DOI: 10.1111/j.1365-2966.2011.17943.x
Abstract: We discuss the characteristics of known extremely metal-poor (EMP) stars in the Galaxy using the Stellar Abundances for Galactic Archaeology (SAGA) database (Suda et al. 2008, PASJ, 60, 1159).The analyses of carbon-enhanced stars in our sample suggest that the nucleosynthesis in AGB stars can contribute to the carbon enrichment in a different way depending on whether the metallicity is above or below [Fe/H] ~ -2.5, which is consistent with the current models of stellar evolution at low metallicity. We find the transition of the initial mass function at [Fe/H] ~ -2 in the viewpoint of the distribution of carbon abundance and the frequency of carbon-enhanced stars. For observed EMP stars, we confirmed that some, not all, of observed stars might have undergone at least two types of extra mixing to change their surface abundances. One is to deplete the lithium abundance during the early phase of red giant branch. Another is to decrease the C/N ratio by one order of magnitude during the red giant branch phase. Observed small scatters of abundances for alpha-elements and iron-group elements suggest that the chemical enrichment of our Galaxy takes place in a well-mixed interstellar medium. We find that the abundance trends of alpha-elements are highly correlated with each other, while the abundances of iron-group elements are subject to different slopes relative to the iron abundance. This implies that the supernova yields of alpha-elements are almost independent of mass and metallicity, while those of iron-group elements have a metallicity dependence or mass dependence with the variable initial mass function.The occurrence of the hot bottom burning in the mass range of 5 <~ M / Msun <~ 6 is consistent with the initial mass function of the Galaxy peaked at ~ 10 - 12 Msun to be compatible with the statistics of carbon enhanced stars with and without s-process element (truncated)
Self Assembly of Honeycomb TiO2 Coatings by Tea-Leaf Extracts as the Dispersoids  [PDF]
Masayuki Kamei
World Journal of Condensed Matter Physics (WJCMP) , 2011, DOI: 10.4236/wjcmp.2011.13010
Abstract: Photo catalytic TiO2 coatings with well defined honeycomb structure were successfully self-assembled on glass substrates by a simple “dip and burn solgel method“. The crux of this new method is that the starting material for the sol-gel coating (the water solution of ammonium titanium citrate) was “doped” with “tea-leaf extracts”. Tea-leaf extracts were completely dissolved in the water solution of ammonium titanium citrate and nucleate uniformly during the drying procedure of the coating precursor formation. This uniformly dispersed nucleation of the “tea-leaf extracts (tannin, catechin…)” were extracted during calcinations and leaving honeycomb-cell like nano-structure in the TiO2 coatings. Self-assembled cells were uniformly distributed in the TiO2 coatings and the diameter of the cells was in the range of 200 - 1000 nm. Fine honeycomb structures were clearly observed with microscopic observations.
A Pure Theory of Aggregate Price Determination  [PDF]
Masayuki Otaki
Theoretical Economics Letters (TEL) , 2011, DOI: 10.4236/tel.2011.13026
Abstract: This article considers aggregate price determination related to the neutrality of money. When the true cost of living can be defined as a function of prices in an overlapping generations (OLG) model, the marginal cost of a firm depends solely on the current and future prices. Thus, the sequence of equilibrium price becomes independent of the quantity of money. Hence, money becomes non-neutral. However, when people hold the extraneous belief that prices increases proportionately with money, this belief becomes self-fulfilling as long as the increment of money and true cost of living are low enough to guarantee full employment.
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