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Search Results: 1 - 10 of 333 matches for " Satoko Takizawa "
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Use of Non-Amplified RNA Samples for Microarray Analysis of Gene Expression
Hiroko Sudo, Atsuko Mizoguchi, Junpei Kawauchi, Hideo Akiyama, Satoko Takizawa
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0031397
Abstract: Demand for high quality gene expression data has driven the development of revolutionary microarray technologies. The quality of the data is affected by the performance of the microarray platform as well as how the nucleic acid targets are prepared. The most common method for target nucleic acid preparation includes in vitro transcription amplification of the sample RNA. Although this method requires a small amount of starting material and is reported to have high reproducibility, there are also technical disadvantages such as amplification bias and the long, laborious protocol. Using RNA derived from human brain, breast and colon, we demonstrate that a non-amplification method, which was previously shown to be inferior, could be transformed to a highly quantitative method with a dynamic range of five orders of magnitude. Furthermore, the correlation coefficient calculated by comparing microarray assays using non-amplified samples with qRT-PCR assays was approximately 0.9, a value much higher than when samples were prepared using amplification methods. Our results were also compared with data from various microarray platforms studied in the MicroArray Quality Control (MAQC) project. In combination with micro-columnar 3D-Gene? microarray, this non-amplification method is applicable to a variety of genetic analyses, including biomarker screening and diagnostic tests for cancer.
MicroRNA Profile Predicts Recurrence after Resection in Patients with Hepatocellular Carcinoma within the Milan Criteria
Fumiaki Sato,Etsuro Hatano,Koji Kitamura,Akira Myomoto,Takeshi Fujiwara,Satoko Takizawa,Soken Tsuchiya,Gozoh Tsujimoto,Shinji Uemoto,Kazuharu Shimizu
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0016435
Abstract: Hepatocellular carcinoma (HCC) is difficult to manage due to the high frequency of post-surgical recurrence. Early detection of the HCC recurrence after liver resection is important in making further therapeutic options, such as salvage liver transplantation. In this study, we utilized microRNA expression profiling to assess the risk of HCC recurrence after liver resection.
Multifactorial study of mobile phone dependence in medical students: Relationship to health-related lifestyle, Type A behavior, and depressive state  [PDF]
Masahiro Toda, Satoko Ezoe
Open Journal of Preventive Medicine (OJPM) , 2013, DOI: 10.4236/ojpm.2013.31012
Abstract: We investigated factors contributing to mobile phone dependence. To 139 medical students, we administered a self-reporting questionnaire designed to evaluate mobile phone dependence, health-related lifestyle, patterns of behavior, and depressive state. Multivariate logistic regression analysis revealed that scores for poor health-related lifestyle, Type A behavior pattern, and presence of depression are independently associated with degree of mobile phone dependency. These findings suggest that persons with an unhealthy lifestyle, Type A behavior traits, or depression might benefit from mobile phone use guidance.
Relationships of loneliness and mobile phone dependence with Internet addiction in Japanese medical students  [PDF]
Satoko Ezoe, Masahiro Toda
Open Journal of Preventive Medicine (OJPM) , 2013, DOI: 10.4236/ojpm.2013.36055
Abstract: We investigated factors contributing to Internet addiction in 105 Japanese medical students. The subjects were administered by a self-reporting questionnaire designed to evaluate demographic factors, Internet addiction, loneliness, health-related lifestyle factors, depressive state, patterns of behavior, and mobile phone dependence. Results of multivariate logistic regression analysis indicated that loneliness and mobile phone dependence were positively related to degree of addiction. Our findings suggest that Internet addiction is associated with loneliness and mobile phone dependence in Japanese students.
Cardiac Arrest Cases and Automated External Defibrillator Use in Railroad Stations in Tokyo  [PDF]
Satoko Fukuike, Yasuhiro Otomo
International Journal of Clinical Medicine (IJCM) , 2014, DOI: 10.4236/ijcm.2014.520170
Abstract: Objective: Nationwide dissemination of public-access defibrillation (PAD) contributed to an increase of survival rate in Japan. We analysed cardiac arrests (CAs) that occurred in railroad stations in Tokyo to evaluate PAD in the metropolis. Methods: We collected Utstein data from the Tokyo Fire Department (TFD) and analysed CA cases that occurred in stations. In total, 245 non-traumatic CAs from January 1, 2007 to March 31, 2008 were analysed; CAs in children under 8 years were excluded. Results: The rates of pre-hospital return of spontaneous circulation (ROSC) were 41 out of 145 witnessed CA patients (28.3%) and 12 ROSC out of 100 unwitnessed CA patients (12%). Of 245 CA cases, bystander cardiopulmonary resuscitation (CPR) performed in 156 (63.7%), automated external defibrillator (AED) used in 117 (47.8%) and shock delivered in 65 (26.5%). Rates of ROSC were 31.6% (37/117) with AED use significantly higher than those of 12.5% (16/128) without AED use (P < 0.001). Most CAs occurred on platforms; the use of AEDs on platforms increased from 18/31 (58.1%) in 2007 to 32/43 (74.4%) in 2008 and ROSC rates increased from 8 (25.8%) to 14 (32.6%), respectively. On train CAs: ROSC cases were very few, 1 case each year (8.3%; 7.7%) while the use of AED increased from 8/12 (66.7%) in 2007 to 10/13 (76.9%) in 2008. Conclusion: Bystander CPR and the use of AED at railroad stations improved ROSC for out-of-hospital cardiac arrest (OHCA) patients. AED location and strategies for dealing with CAs on trains should be re-evaluated.
La continuidad de la mentalidad medieval europea en la misión de Japón –en torno a la política de evangelización–
Takizawa, Osami
Hispania Sacra : Revista de Historia Eclesiástica , 2010,
Abstract: From the analysis of the documents of the Jesuits who worked in Japan between the XVI and XVII centuries, we can note the methods of evangelization put into practice by Francisco Javier and the Jesuits who followed his mission. Firstly, the Jesuits aimed at baptizing the feudal lord as a way that eased the path to the conversion of their respective vassals. Secondly, the Jesuits tried to extend the Christianism among monks and intellectuals and thereafter among the common people. It can be questioned if the methods used showed any similarity with the evangelization in the Medieval Time in Europe, if the Europeans applied such Medieval methods in the Japanese society. The purpose of this article is to analyse these questions. Al analizar los documentos de los jesuitas que trabajaron en evangelización que pusieron en marcha Francisco Javier y los jesuitas que continuaron su misión. Primero, los jesuitas procuraron bautizar a los se ores feudales, como vía que allanaba el camino a la conversión de sus vasallos. Segundo, los jesuitas intentaron extender el cristianismo entre los bonzos e intelectuales y después en el pueblo llano. Cabe preguntarse si los métodos utilizados presentan similitudes con la evangelización en la Edad Media en Europa, si los europeos aplicaron estos métodos medievales en la sociedad japonesa. El objeto de este artículo es analizar estas cuestiones.
Two-Temperature Intracluster Medium in Merging Clusters of Galaxies
Motokazu Takizawa
Physics , 1999, DOI: 10.1086/307497
Abstract: We investigate the evolution of intracluster medium during a cluster merger, explicitly considering the relaxation process between the ions and electrons by N-body and hydrodynamical simulations. When two subclusters collide each other, a bow shock is formed between the centers of two substructures and propagate in both directions along the collision axis. The shock primarily heats the ions because the kinetic energy of an ion entering the shock is larger than that of an electron by the ratio of masses. In the post-shock region the energy is transported from the ions to electrons via Coulomb coupling. However, since the energy exchange timescale depends both on the gas density and temperature, distribution of electron temperature becomes more complex than that of the plasma mean temperature, especially in the expanding phase. After the collision of two subclusters, gas outflow occurs not only along the collision axis but also in its perpendicular direction. The gas which is originally located in the central part of the subclusters moves both in the parallel and perpendicular directions. Since the equilibrium timescale of the gas along these directions is relatively short, temperature difference between ions and electrons is larger in the directions tilted by the angles of $\pm 45^\circ$ with respect to the collision axis. The electron temperature could be significantly lower that the plasma mean temperature by $\sim 50 %$ at most. The significance of our results in the interpretation of X-ray observations is briefly discussed.
A Two-Temperature Model of the Intracluster Medium
Motokazu Takizawa
Physics , 1998, DOI: 10.1086/306530
Abstract: We investigate evolution of the intracluster medium (ICM), considering the relaxation process between the ions and electrons. According to the standard scenario of structure formation, ICM is heated by the shock in the accretion flow to the gravitational potential well of the dark halo. The shock primarily heats the ions because the kinetic energy of an ion entering the shock is larger than that of an electron by the ratio of masses. Then the electrons and ions exchange the energy through coulomb collisions and reach the equilibrium. From simple order estimation we find that the region where the electron temperature is considerably lower than the ion temperature spreads out on a Mpc scale. We then calculate the ion and electron temperature profiles by combining the adiabatic model of two-temperature plasma by Fox & Loeb (1997) with spherically symmetric N-body and hydrodynamic simulations based on three different cosmological models. It is found that the electron temperature is about a half of the mean temperature at radii $\sim$ 1 Mpc. This could lead to an about 50 % underestimation in the total mass contained within $\sim$ 1 Mpc when the electron temperature profiles are used. The polytropic indices of the electron temperature profiles are $\simeq 1.5$ whereas those of mean temperature $\simeq 1.3$ for $r \geq 1$ Mpc. This result is consistent both with the X-ray observations on electron temperature profiles and with some theoretical and numerical predictions about mean temperature profiles.
Evolution of Hard X-Ray Radiation from Clusters of Galaxies: Bremsstrahlung or Inverse Compton Scattering?
Motokazu Takizawa
Physics , 2002, DOI: 10.1093/pasj/54.3.363
Abstract: We have calculated evolution of a non-thermal electron population from super-thermal but weakly relativistic to highly relativistic energy range in clusters of galaxies. We investigate evolution of hard X-ray radiation due to both bremsstrahlung and inverse Compton scattering of the cosmic microwave background photons. The bremsstrahlung component is more significant than the inverse Compton scattering one when the momentum spectra of electron sources are steeper than $\sim P_e^{-3.0}$ and vice versa in the case of Coma, where $P_e$ is an electron momentum. The resultant hard X-ray spectra are flatter when the bremsstrahlung component is dominant. When the spectral indices of the source term are in the intermediate range ($ -2.5 \sim -3.5$), too much extreme ultraviolet emission is produced. Inverse Compton dominant models can reproduce Coma cluster results with reasonable injection rates, which are possible in cluster mergers and/or ambient gas accretion.
Off-Center Mergers of Clusters of Galaxies and Nonequipartition of Electrons and Ions in Intracluster Medium
Motokazu Takizawa
Physics , 1999, DOI: 10.1086/308550
Abstract: We investigate the dynamical evolution of clusters of galaxies and their observational consequences during off-center mergers, explicitly considering the relaxation process between ions and electrons in intracluster medium by N-body and hydrodynamical simulations. In the contracting phase a bow shock is formed between the two subclusters. The observed temperature between two peaks in this phase depends on the viewing angle even if the geometry of the system seems to be very simple like head-on collisions. Around the most contracting epoch, when we observe merging clusters nearly along the collision axis, they look like spherical relaxed clusters with large temperature gradients. In the expanding phase, spiral bow shocks occur. As in head-on mergers, the electron temperature is significantly lower than the plasma mean one especially in the post-shock regions in the expanding phase. When the systems have relatively large angular momentum, double-peak structures in the X-ray images can survive even after the most contracting epoch. Morphological features in both X-ray images and electron temperature distribution characteristic to off-center mergers are seriously affected by the viewing angle. When the clusters are observed nearly along the collision axis, the distribution of galaxies' line-of-sight (LOS) velocities is a good indicator of mergers. In the contracting phase, an negative kurtosis and a large skewness are expected for nearly equal mass collisions and rather different mass ones, respectively. To obtain statistically significant results, about 1000 galaxies' LOS velocities are required. For nearby clusters ($z<0.05$), large redshift surveys such as 2dF will enable us to study merger dynamics.
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