Multi-MW Closed Cycle MHD Nuclear Space Power Via Nonequilibrium He/Xe Working Plasma

Prospects for a low specific mass multi-megawatt nuclear space power plant were examined assuming closed cycle coupling of a high-temperature fission reactor with magnetohydrodynamic (MHD) energy conversion and utilization of a nonequilibrium helium/xenon frozen inert plasma (FIP). Critical evaluation of performance attributes and specific mass characteristics was based on a comprehensive systems analysis assuming a reactor operating temperature of 1800 K for a range of subsystem mass properties. Total plant efficiency was expected to be 55.2% including plasma pre-ionization power, and the effects of compressor stage number, regenerator efficiency and radiation cooler temperature on plant efficiency were assessed. Optimal specific mass characteristics were found to be dependent on overall power plant scale with 3 kg/kWe being potentially achievable at a net electrical power output of 1-MWe. This figure drops to less than 2 kg/kWe when power output exceeds 3 MWe. Key technical issues include identification of effective methods for non-equilibrium pre-ionization and achievement of frozen inert plasma conditions within the MHD generator channel. A three-phase research and development strategy is proposed encompassing Phase-I Proof of Principle Experiments, a Phase-II Subscale Power Generation Experiment, and a Phase-III Closed-Loop Prototypical Laboratory Demonstration Test

Behavioral Analysis of Genetically Modified Mice Indicates Essential Roles of Neurosteroidal Estrogen

Aromatase in the mouse brain is expressed only in the nerve cells of specific brain regions with a transient peak during the neonatal period when sexual behaviors become organized. The aromatase-knockout (ArKO) mouse, generated to shed light on the physiological functions of estrogen in the brain, exhibited various abnormal behaviors, concomitant with undetectable estrogen and increased androgen in the blood. To further elucidate the effects of neurosteroidal estrogens on behavioral phenotypes, we first prepared an brain-specific aromatase transgenic (bsArTG) mouse by introduction of a human aromatase transgene controlled under a −6.5 kb upstream region of the brain-specific promoter of the mouse aromatase gene into fertilized mouse eggs, because the −6.5 kb promoter region was previously shown to contain the minimal essential element responsible for brain-specific spatiotemporal expression. Then, an ArKO mouse expressing the human aromatase only in the brain was generated by crossing the bsArTG mouse with the ArKO mouse. The resulting mice (ArKO/bsArTG mice) nearly recovered from abnormal sexual, aggressive, and locomotive (exploratory) behaviors, in spite of having almost the same serum levels of estrogen and androgen as the adult ArKO mouse. These results suggest that estrogens locally synthesized in the specific neurons of the perinatal mouse brain directly act on the neurons and play crucial roles in the organization of neuronal networks participating in the control of sexual, aggressive, and locomotive (exploratory) behaviors

Ion current density profile of laser ablation plasma transported in multicusp magnetic field

Laser ion sources are capable of supplying ion beams with high current because a laser produced plasma has initially high number density same as that of solid. [1]..

膵硬度計による膵切除後の膵液瘻発生予測と膵組織の繊維化予測に関する研究

学位の種別: 課程博士審査委員会委員 : （主査）東京大学教授 大友 邦, 東京大学講師 山下 裕玄, 東京大学准教授 田村 純人, 東京大学講師 赤井 宏行, 東京大学准教授 伊佐山 浩通University of Tokyo(東京大学

Intratumoural mRNA expression of genes from the oestradiol metabolic pathway and clinical and histopathological parameters of breast cancer

INTRODUCTION: The expression of the oestrogen receptor (ER) is one of the more important clinical parameters of breast cancer. However, the relationship between the ER and its ligand, oestradiol, and the enzymes that synthesise it are not well understood. The expression of mRNA transcripts of members of the oestradiol metabolic and signalling pathways including the ER was studied in detail. METHOD: mRNA transcripts for aromatase (CYP19), 17-β-hydroxysteroid dehydrogenase I, 17-β-hydroxysteroid dehydrogenase II, ERα, ERβ, steroid sulfatase (STS), oestradiol sulfotransferase (EST), cyclin D(1 )(CYCLD1) and ERBB2 were fluorometrically quantified by competitive RT-PCR using an internal standard in 155 breast carcinomas. In addition, the transcripts of CYP19 were analysed for alternative splicing/usage of exon 1 and an alternative poly A tail. RESULTS: A great variability of expression was observed, ranging from 0 to 2376 amol/mg RNA. The highest levels were observed for STS and EST, and the lowest levels (close to zero) were observed for the 17-β-hydroxysteroid dehydrogenase isoenzymes. The levels of mRNA expression were analysed with respect to clinical and histopathological parameters as well as for disease-free survival. High correlation of the mRNA expression of STS, EST and 17-β-hydroxysteroid dehydrogenase in the tumours suggested a common regulation, possibly by their common metabolite (oestradiol). Hierarchical clustering analysis in the 155 patients resulted in two main clusters, representing the ERα-negative and ERα-positive breast cancer cases. The mRNA expression of the oestradiol metabolising enzymes did not follow the expression of the ERα in all cases, leading to the formation of several subclasses of tumours. Patients with no expression of CYP19 and patients with high levels of expression of STS had significantly shorter disease-free survival time (P > 0.0005 and P < 0.03, respectively). Expression of ERβ mRNA was a better prognostic factor than that of ERα in this material. CONCLUSION: Our results indicate the importance of CYP19 and the enzymes regulating the oestrone sulfate metabolism as factors of disease-free survival in breast cancer, in addition to the well-known factors ER and ERBB2

Laser-induced-fluorescence measurement of thermal conductivity in warm dense matter generated by pulsed-power discharge

Thermal conductivity in warm dense matter is one of the interests for thermonuclear fusion scenarios. Alternative inertial confinement fusion, which is a fast ignition with applied magnetic field [1], has been considered to improve the coupling efficiency. The target behavior of the fast ignition with applied magnetic field depends on the anisotropic thermal conductivity. The magnetic confinement fusion (MCF) [2] Up to now, the heat load on the divertor in previous MCF systems has been unreached parameter. Thus, to predict properties of the divertor under these heat loads, several experiments have been performed using several methods[3-6]. To predict the performance of the tungsten divertor in MCF, we should analyze not only metallurgical properties but also thermophysical properties of ablated tungsten..

Laser-induced-fluorescence measurement of thermal conductivity in warm dense matter generated by pulsed-power discharge

Thermal conductivity in warm dense matter is one of the interests for thermonuclear fusion scenarios. Alternative inertial confinement fusion, which is a fast ignition with applied magnetic field [1], has been considered to improve the coupling efficiency. The target behavior of the fast ignition with applied magnetic field depends on the anisotropic thermal conductivity. The magnetic confinement fusion (MCF) [2] Up to now, the heat load on the divertor in previous MCF systems has been unreached parameter. Thus, to predict properties of the divertor under these heat loads, several experiments have been performed using several methods[3-6]. To predict the performance of the tungsten divertor in MCF, we should analyze not only metallurgical properties but also thermophysical properties of ablated tungsten..

Recent activity on beam dynamics study during longitudinal bunch compression by using compact beam simulators for heavy ion inertial fusion

In heavy ion inertial fusion scenario, heavy ion beams with extreme high current are most important assignment [1]. Predictions of beam behavior are basic necessity to design the accelerator complex. Especially, a bunch compression manipulation in the final stage of accelerator complex is required to generate the beam with high current and suitable short pulse duration [2]..

Recent activity on beam dynamics study during longitudinal bunch compression by using compact beam simulators for heavy ion inertial fusion

In heavy ion inertial fusion scenario, heavy ion beams with extreme high current are most important assignment [1]. Predictions of beam behavior are basic necessity to design the accelerator complex. Especially, a bunch compression manipulation in the final stage of accelerator complex is required to generate the beam with high current and suitable short pulse duration [2]..