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Aromatase, a key enzyme of estrogen biosynthesis, is transcriptionally regulated by many growth factors. IGF-I enhances aromatase activity in a variety of cells, but the mechanism of action has not been determined. We herein report our finding of a novel mechanism of action for IGF-I. IGF-I enhanced the dexamethasone (DEX)-induced aromatase activity by 30% in serum-starved THP-1 cells. The increase was associated with a corresponding increase in the level of aromatase protein but not with any change in the mRNA level. Metabolic labeling experiments revealed that IGF-I inhibited the degradation of aromatase. We identified pepstatin A as the most effective inhibitor of aromatase degradation by in vitro assay. Using a nontoxic concentration of pepstatin A, we examined IGF-I’s action on aromatase distribution in microsomes and lysosomes. In the presence of pepstatin A, DEX caused an increase in the amount of aromatase in both microsomes and lysosomes, and IGF-I attenuated the DEX-induced accumulation of aromatase in lysosomes and, conversely, enhanced its accumulation in the microsomes. The addition of serum abolished the IGF-I-induced changes. The transport from microsome to lysosome was fluorescently traced in cells using a recombinant aromatase. IGF-I selectively reduced the aromatase signal in the lysosomes. Finally, we observed that IGF-I enhanced the aromatase activity by 50% as early as 1 h after treatment; furthermore, rapamycin, an enhancer of autophagy, completely negated the effect of IGF-I on the enzyme. These results indicate that IGF-I enhances aromatase by the inhibition of autophagy.

Introduction: Laparoscopic hepatectomy has disadvantages in intraoperative diagnosis, because it offers limited visualization and palpability of the liver surface. Recently, we developed a novel fluorescent imaging technique using indocyanine green (ICG), which would enable identification of liver cancers during open hepatectomy. However, this technique has not yet been applied to laparoscopic hepatectomy. Materials and Surgical Technique: A patient with a hepatocellular carcinoma (HCC) located in Couinaud's segment II was administered ICG (0.5 mg per kg body weight) intravenous injection 5 d before surgery, as a routine liver function test. The prototype fluorescent imaging system was composed of a xenon light source and a laparoscope with a charge-coupled device camera that could filter out light with wavelengths below 810 nm. Intraoperatively, fluorescent imaging of the HCC was performed by changing color images to fluorescent images with a foot switch. Then, the fluorescing tumor was clearly identified on the visceral surface of segment II during mobilization of the left liver for resection of segments II and III. On the cut surface of the specimen, the tumor showed uniform fluorescence and was microscopically diagnosed as a well-differentiated HCC. Discussion: Laparoscopic fluorescent imaging using preoperative injection of ICG enabled real-time identification of HCC. This technique may be an easy and reliable tool to enhance the accuracy of intraoperative diagnosis during laparoscopic hepatectomy.

This paper studies physical phenomena, performance and optimal operating point of an AC MHD generator under the slip value by using a numerical simulation. The double-side exciting winding of the generator is considered. Its structure consists of a channel, an insulator and stators. Channel type is a flat rectangular and the liquid flows along the channel as a conductor. Channel wall acted as an insulator separates metal fluid and stator coils. The top and bottom stator winding of the generator is connected to polyphase system. Under this condition, it can produce a magnetic field by means of time harmonic function in the same direction of the metal fluid. An interaction between traveling wave and metal fluid is explained by finite element method under Maxwell's equation and Ohm law. The distribution of magnetic vector potential and magnetic flux density throughout channel is evidently shown in xy-plane. Power flow in AC MHD generator is evaluated by slip value. The optimal operating point of an AC MHD generator performance is reported by active power 0.99kW, reactive power 50kVAR, mechanical power 1.58kW, power dissipation 0.59kW and electrical efficiency 62.5%.

This paper presents the investigation of ablation plasma characteristics together with the flyer velocity for flyer acceleration when irradiating the 50-μm-Al target with a multi-pulsed ion beam. A one-dimensional hydrodynamic model is used in the calculations. The CIP method is used to describe the ablation plasma production and the acceleration mechanism by the repetition of ion beam irradiation. In the calculations, two shots of ion beam, which has a total energy density of 120 J/cm 2 , are used. The time intervals between the first pulse and the second pulse of 0 ns, 20 ns, 50 ns and 100 ns were used for the investigation of flyer (target) velocity. Results indicate that irradiating the second pulse for 20 ns, 50 ns and 100 ns after the first pulse increases the flyer velocity by approximately 16%, 32% and 40%, respectively.

In this study, the possible application of atmospheric pressure dielectric barrier discharge plasma for the annealing of metallic wire is examined and presented. The main purpose of the current study is to examine the surface cleaning effect for a cylindrical object by atmospheric pressure plasma. The experimental setup consists of a gas tank, plasma reactor, and power supply with control panel. The gas assists in the generation of plasma. Copper wire was used as an experimental cylindrical object. This copper wire was irradiated with the plasma, and the cleaning effect was confirmed. The result showed that it is possible to remove the tarnish which exists on the copper wire surface. The experiment reveals that atmospheric pressure plasma is usable for the surface cleaning of metal wire. However, it is necessary to examine the method for preventing oxidization of the copper wire.

SummarySex hormones are essential for neural circuit development and sex-specific behaviors. Male behaviors require both testosterone and estrogen, but it is unclear how the two hormonal pathways intersect. Circulating testosterone activates the androgen receptor (AR) and is also converted into estrogen in the brain via aromatase. We demonstrate extensive sexual dimorphism in the number and projections of aromatase-expressing neurons. The masculinization of these cells is independent of AR but can be induced in females by either testosterone or estrogen, indicating a role for aromatase in sexual differentiation of these neurons. We provide evidence suggesting that aromatase is also important in activating male-specific aggression and urine marking because these behaviors can be elicited by testosterone in males mutant for AR and in females subjected to neonatal estrogen exposure. Our results suggest that aromatization of testosterone into estrogen is important for the development and activation of neural circuits that control male territorial behaviors.

Domestic pigs have three CYP19 genes encoding functional paralogues of the enzyme aromatase cytochrome P450 (P450arom) that are expressed in the gonads, placenta, and preimplantation blastocyst. All catalyze estrogen synthesis, but the gonadal-type enzyme is unique in also synthesizing a nonaromatizable biopotent testosterone metabolite, 1OH-testosterone (1OH-T). P450arom is expressed in the vertebrate brain, is higher in males than females, but has not been investigated in pigs, to our knowledge. Therefore, these studies defined which of the porcine CYP19 genes was expressed, and at what level, in adult male and female hypothalamus. Regional expression was examined in mature boars, and regulation of P450arom expression in neonatal boars was investigated by inhibition of P450arom with letrozole, which is known to reprogram testicular expression. Pig hypothalami expressed the gonadal form of P450arom (redesignated the "gonadal/hypothalamic" porcine CYP19 gene and paralogue) based on functional analysis confirmed by cloning and sequencing transcripts. Hypothalamic tissue synthesized 1OH-T and was sensitive to the selective P450arom inhibitor etomidate. Levels were 4-fold higher in male than female hypothalami, with expression in the medial preoptic area and lateral borders of the ventromedial hypothalamus of boars. In vivo, letrozole-treated neonates had increased aromatase activity in hypothalami but decreased activity in testes. Therefore, although the same CYP19 gene is expressed in both tissues, expression is regulated differently in the hypothalamus than testis. These investigations, the first such studies in pig brain to our knowledge, demonstrate unusual aspects of P450arom expression and regulation in the hypothalamus, offering promise of gaining better insight into roles of P450arom in reproductive function.

PHYSIOL BEH Exposure to estrogens during critical developmental periods and in adulthood affects sex differences in the brain. We examined the roles of estradiol (E2) and phytoestrogens, and their interactions, on potential sex differences in brain. We used aromatase knockout (ArKO) mice, which cannot produce endogenous estrogens, along with wild type (WT) littermates. Mice were gestated, raised and maintained on a diet either rich in phytoestrogens or a diet virtually void of soy-derived phytoestrogens. Adult males and females were gonadectomized and received implants filled with 17-β-estradiol to induce progestin receptors (PR), while controls received empty implants. Mice were sacrificed five days later and brain sections containing the posterodorsal medial amygdala (MePD) were processed for PR immunoreactivity. Activation of sex differences in PR required adult E2 treatment. A diet high in phytoestrogens was required for expression of sex differences in PR after E2 treatment. Our data underscore the important contribution of dietary phytoestrogens for the development of sex differences in PR-ir in the adult mouse medial amygdala. We hypothesize that both aromatization of androgens to estrogens and dietary sources of additional estrogens are part of the normal requirement for sex differences in the rodent brain.

In the our study, an improvement of the tear strength of the bonded resin material using an atmospheric dielectric barrier discharge plasma treatment is described. The surface treatment experiments were carried out on the surface of the polyimid films with the air and the air with an argon as a operation gas for various treatment times. The 20 kVP-P, 2 AP-P and 45 kHz power supply was used to produce an atmospheric discharge plasma with the mixture of air and small amount of argon. The contact angle on the treated surface was significantly decreased from 40-50 degree to less than 10 degree by the this plasma treatment. This suggested the removal of the organic contaminant and the enhancement of the wettability to an adhesive. The peeling test of the bonded resin materials was adopted to study the tear strength in both cases with and without plasma treatment. The results showed that the tear strength was successfully improved by more than 3 times of that measured for the bonded un-treated films. We could conclude that the surface of the polyimid film was successfully treated by the atmospheric dielectric barrier discharge plasma and that the organic contaminants which inhibited the adhesion was removed. In addition, the adhesive property also affects rough surface effect and active effect of the surface(1)-(3). And the adhesive property can be improved by them. As a result, a significant improvement of the tear strength of the resin materials was achieved.

Female gender is a risk factor for drug-induced arrhythmias associated with QT prolongation, which results mostly from blockade of the human ether-a-go-go-related gene (hERG) channel. Some clinical evidence suggests that oestrogen is a determinant of the gender-differences in drug-induced QT prolongation and baseline QTC intervals. Although the chronic effects of oestrogen have been studied, it remains unclear whether the gender differences are due entirely to transcriptional regulations through oestrogen receptors. We therefore investigated acute effects of the most bioactive oestrogen, 17β-oestradiol (E2) at its physiological concentrations on cardiac repolarization and drug-sensitivity of the hERG (IKr) channel in Langendorff-perfused guinea pig hearts, patch-clamped guinea pig cardiomyocytes and culture cells over-expressing hERG. We found that physiological concentrations of E2 partially suppressed IKr in a receptor-independent manner. E2-induced modification of voltage-dependence causes partial suppression of hERG currents. Mutagenesis studies showed that a common drug-binding residue at the inner pore cavity was critical for the effects of E2 on the hERG channel. Furthermore, E2 enhanced both hERG suppression and QTC prolongation by its blocker, E4031. The lack of effects of testosterone at its physiological concentrations on both of hERG currents and E4031-sensitivity of the hERG channel implicates the critical role of aromatic centroid present in E2 but not in testosterone. Our data indicate that E2 acutely affects the hERG channel gating and the E4031-induced QTC prolongation, and may provide a novel mechanism for the higher susceptibility to drug-induced arrhythmia in women.

The purpose of this study is to clarify effects of three-dimensional phenomena on performance of the Magnetohydrodynamic (MHD) accelerator for the MAPX project at NASA Marshal Space Flight Center. Generally, in a Faraday type of MHD accelerator with segmented electrode, high flow velocity augmentation can be achieved. However, many independent power supplies have to be installed. A diagonal type of MHD accelerator requires only one power supply, and it is hopeful for the practical applications. Hall current neutralized condition was proposed in this study where each electrode pair was linked externally so as to cancel the current caused by the Hall effect. Results showed that the diagonal accelerator with the neutralized condition could achieve an outlet velocity equivalent to that in the Faraday accelerator. The axial velocity augmented from 1235m/s at inlet to 3040m/s at the outlet under the 300Amps of load current. It is found that the neutralized condition was not implemented in a whole of the cross section when there was plasma non-uniformity. The Lorentz force due to the current concentration caused the velocity-overshoot and the secondary flows. This study of the 3-D analysis provided prediction of the plasma behavior in an MHD accelerator channel as prior numerical analysis for the MAPX project carried out at NASA Marshall Space Flight Center.

Steroid hormones act on developing neural circuits that regulate the hypothalamic-pituitary-gonadal axis and are involved in hormone-sensitive behaviours. To test the hypothesis that developmental exposure to oestradiol (E(2)) organises the quantity of adult oestrogen receptors (ERalpha and ERbeta), we used male mice with a targeted mutation of the aromatase enzyme gene (ArKO) and their wild-type (WT) littermates. These mice are unable to aromatise testosterone to E(2), but still express both ERalpha and beta. To evaluate adult responsiveness to E(2), gonadectomised males were implanted with Silastic capsules containing E(2), or an empty implant, 5 days prior to sacrifice. Immunoreactivity for ERalpha and ERbeta was quantified in the caudal ventromedial nucleus (VMN) and the medial preoptic area (POA). Regardless of genotype, adult treatment with E(2) reduced ERalpha-immunoreactive (ir) and ERbeta-ir cell numbers in the POA, as well as ERbeta-ir, but not ERalpha-ir, cell numbers in the VMN. Genotype, and thus endogenous exposure to E(2), produced opposite effects on ER expression in the two brain areas. In the VMN, ArKO males had more ERalpha-ir and ERbeta-ir cells than did WT males. In the POA, ArKO males had fewer ERalpha-ir and ERbeta-ir cells than did WT males. Thus, numbers of immunoreactive neurones containing both ERs in the adult ArKO male were enhanced in the POA, but decreased in the VMN, and most likely these patterns were established during the developmental critical period. Furthermore, although both ERalpha and beta-ir cell numbers are altered by the disruption of the aromatase gene, ERbeta is altered in a more robust and region-specific manner.

The numerical solution of a magnetoplasmadynamics accelerator intended for supersonic airbreathing propulsion systems is presented. The numerical method solves the Favre-averaged Navier-Stokes equations closed by the Wilcox kw model, including the nitrogen vibrational energy and a finite rate chemical solver accounting for electron-beam ionization, electron attachment, and dissociative recombination. The fluid-flow equations are solved in conjunction with the electric-field-potential equation. Because of the recombination time of the electrons with the charged particles being in the order of microseconds, the interaction region is more or less confined to the area when e-beam ionization is applied. In this manner, a Faraday-type configuration can be obtained by using only one electrode pair. The impact of the length of the interaction region and the strength of the magnetic field on the efficiency are assessed. It is observed that the efficiency obtained numerically is as much as 40% less than the theoretical predictions for the highest magnetic field considered of 4 T. This is attributed to 1) the current concentration near the electrodes' edges causing a significant voltage drop and 2) unsteady behavior in the center of the channel due to the interaction between finite rate chemistry and electromagnetism. Nonetheless, an efficiency within 25% of the theoretical predictions can be obtained at high magnetic field by decreasing the width of the interaction region to one-tenth of its height.

A magnetohydrodynamic (MHD) accelerator is proposed as a next generation propulsion system. The fundamental acceleration performance has been, so far, evaluated using one-dimensional (1-D) numerical analysis. However, the actual phenomena in the accelerator channel are highly coupled with boundary layers and with electrode phenomena and are three-dimensional. In this paper, research for investigating the three-dimensional (3-D) phenomena of an MHD accelerator is described. The validity of the 3-D numerical analysis is assessed through comparisons with the results of 1-D analysis. An existence of a local Hall current not predicted through 1-D analysis enhances the Joule dissipation and induces a secondary flow. It was found that a significant local Hall current influences the growth of the velocity overshoot, and this phenomenon is promoted particularly in a high Hall parameter environment. This study of 3-D analysis offers a more realistic prediction of the accelerator performance of the MHD accelerator than that of the 1-D predictions.

The main objective of the current study was to investigate the behavior of ablation plasma which was produced by irradiating pulsed ion-beam with a solid target of Al thin foil. The technique used here was called a forward expansion---beams irradiation and the ablation plasma expansion are in an opposite direction. A one-dimensional hydrodynamic model was used to simulate the dynamic of the target with a thickness of 9 µm and the plasma. In this model, the internal energy together with both of the latent heat of fusion phenomenon and the latent heat of vapor are also taken into account. Physical parameters are presented in terms of ablated plasma temperature, pressure and the energy deposition distribution.

The main objective of the current study is to clarify the influence of ion beam waveform and to investigate the momentum producing capability of flyer acceleration for propulsion applications, which is produced by irradiating target materials with pulsed ion beam. Al thin foil with a thickness of 50 μm was used to form the high-pressure, high-temperature, and high-energy density ablation plasma when it interacts with pulsed ion beam. The analytical procedures are based on one-dimensional hydrodynamic equations together with a real gas equation of state. This paper presents not only the physical parameters of pulsed ion beam interaction with a target, but also shows the effects of ion beam waveform on momentum production. In addition, we describe the mechanism of ablation pressure formation and compare the results obtained for the rectangular and the parabolic waveform of ion beam irradiation. An ion beam with parabolic waveform produces ablation pressure more efficiently than a rectangular waveform. Propulsion performance is also estimated. An impulse bit of 50.7 mNs and a specific impulse of 5200 s are obtained at an electric power consumption of 1677 W.

電磁流体力学(MHD)推進技術は次世代の推進システムとして期待されており，NASAマーシャルスペースフライトセンターではMAPXと呼ばれるMHD加速実験が計画されている．この計画ではダイアゴナル型のMHD加速機の使用が予定されている．チャネル上下に配置された電極を適切に接続することによって，流れの非対称性やジュール加熱を緩和することができ，これはホール電流中和状態と呼ばれる．本論文では，このホール電流中和状態を理論的に評価し，さらに理想的な電極接続状態と実機との違いの影響を見積もった．結果として，両者に多少の違いは生じるが加速機出口における流速に大きな違いはないことを示し，実機においても理想的に評価されたホール電流中和状態をほぼ達成できることを示した．

Our in vitro characterization showed that physiological concentrations of estrogen partially suppressed the I(Kr) channel current in guinea pig ventricular myocytes and the human ether-a-go-go-related gene (hERG) channel currents in CHO-K1 cells regardless of estrogen receptor signaling and revealed that the partially suppressed hERG currents enhanced the sensitivity to the hERG blocker E-4031. To obtain in vivo proof-of-concept data to support the effects of estrogen on cardiac electrophysiology, we here employed an aromatase knockout mouse as an in vivo estrogen-null model and compared the acute effects of E-4031 on cardiac electrophysiological parameters with those in wild-type mice (C57/BL6J) by recording surface electrocardiogram (ECG). The ablation of circulating estrogens blunted the effects of E-4031 on heart rate and QT interval in mice under a denervation condition. Our result provides in vivo proof of principle and demonstrates that endogenous estrogens increase the sensitivity of E-4031 to cardiac electrophysiology.

Telaprevir (TVR), a direct -acting protease inhibitor, was recently reported to improve treatment efficacy when used in combination with peg-interferon (PEG-IFN) and ribavirin (RBV) as triple therapy for HCV in non-transplant patients. The aim of the present study was to investigate the feasibility of TVR-based triple therapy among Japanese living donor liver transplant (LDLT) recipients who had been resistant to dual treatment with PEG-IFN and RBV. Among 133 HCV-positive LDLT recipients, 8 null responders during or after dual treatment with PEG-IFN and RBV were finally indicated for TVR-based triple therapy after treatment. All 8 patients had been resistant to dual treatment with PEG-IFN and RBV. While the cyclosporine trough level was well controlled with an 80% dose reduction during TVR administration, the end - of - treatment response rate was only 25% (2/8), with 63% (5/8) of patients developing anemia that required a blood transfusion and 50% (4/8) of patients developing leukopenia that required filgrastim. Dose reduction or treatment discontinuation was required in all cases. Based on the poor efficacy and the unacceptable high rate of cytopenic events, TVR-based triple therapy is not indicated for those resistant to dual treatment with PEG-IFN and RBV.

Human aromatase is widely expressed in various tissues and shows complicated regulation by both inductive and suppressive factors. The aromatase gene has the unique characteristic of having multiple exons available for use as exon 1, which are flanked with unique promoters. Tissue-specific expression of aromatase is regulated by alternative use of these exons. The exon 1 termed exon I.4 (1b) is the one that is mainly used in breast tissues. However, during cancer development it is often switched from exon I.4 (1b) to exon I.3 (1c) or exon PII (1d), which causes enhancement of aromatase expression in cancer-associated adipocytes and fibroblasts. The aromatase gene is further regulated at both the transcriptional and post-transcriptional levels through PKA-, PKC-, and tyrosine kinase receptor-mediated signaling pathways that employ prostaglandin E2 and class 1 cytokines. Epigenetic modifications of the aromatase gene and microRNA-mediated aromatase regulation may play a critical role in breast cancer progression. Several genetic polymorphisms in the aromatase gene may be prognostic factors of disease and may influence response to aromatase inhibitors.

Investigation of application of magnetohydrodynamic (MHD) acceleration process for advanced propulsion system has significantly increased. The diagonal MHD accelerator is possible for this acceleration technique because of its minimum weight, size and complexity. In this paper, the fundamental performance of a diagonal type MHD accelerator under chemical and thermal equilibrium conditions is described. A one dimensional numerical simulation is performed to characterize the acceleration along the specified channel designed and developed at the NASA Marshall Space Flight Center. In order to solve the set of differential equations with MHD approximations, the MacCormack scheme is employed. In the present calculation, a working gas of air-plasma composed of diatomic molecules of nitrogen and oxygen seeded with potassium is considered in order to actualize application of the MHD accelerator propulsion system. Numerical results show the gasdynamic characteristics (flow velocity, gas pressure and gas temperature), electrical properties (electrical conductivity, Hall parameter and Faraday current density) and electrical efficiency of the MHD accelerator.

Context: Aromatase, steroid sulfatase, and 17β-hydroxysteroid dehydrogenase type 1 (HSD-1) peripherally up-regulate, whereas estrogen sulfotransferase (EST) and HSD-2 down-regulate, the synthesis of active and more potent estrogens. These estrogen-metabolizing enzymes (EMEs) are important in postmenopausal breast cancers, but have never been systematically examined in breast cancers of the elderly. Objective and Design: mRNA levels of EMEs in cancerous and normal breast tissues from 39 elderly patients (age, 80–99 yr) were compared with those from 39 controls (age, 37–70 yr) or compared according to estrogen (ER)/progesterone (PR) receptor status. Results: Aromatase levels were higher in cancers of the elderly (EldCa) than in normal tissue of the elderly (P = 0.0008) or cancers of controls (P = 0.0033). In contrast, levels of steroid sulfatase and EST were higher in cancers of controls than normal tissue of controls (P = 0.0046 and P < 0.0001, respectively) or EldCa (P = 0.0001 and P < 0.0001, respectively). Levels of HSD-1 and HSD-2 did not differ significantly between any two of the categories. Among EldCa, HSD-1 levels were higher in ER/PR-positive than in ER/PR-negative carcinomas, whereas EST and HSD-2 exhibited opposite results. Conclusions: The importance of aromatase is relatively increased in EldCa. ER/PR-positive EldCa exhibited a pattern of EMEs more beneficial to the production of estrogen than did ER/PR-negative EldCa. The specific pattern exhibited in EldCa may elucidate the role of EMEs in the absence of ovarian estrogens in the pathogenesis of breast cancer.

The formation and expansion of the ablation plasmas by ion-beam evaporation (IBE), which was a method of the thin films production using the ablation plasmas deposited on the substrates, were analyzed numerically. We used the one-dimensional hydrodynamic model explained the interaction between the targets and incident ion beams. Changing ion beam angle could control the ablation pressure during the formation of the ablation plasma without significantly changes of the plasma temperature. The expansion velocities of the ablation plasma reached up to the substrates for various target materials were defined by distributions of the ion number densities of the ablation plasmas, and were agreed well with experimental ones observed by high-speed camera. We found out that there was a time lag of the ablation plasma reached up to the substrate between the peak of the plasma ion number density and plasma temperature. The numerical results of the expansion velocities of the ablation plasmas and plasma temperatures could apply to estimate for the production of not only the thin films but also the multi-layered ones.

The aim of this study is to examine a magnetohydrodynamic (MHD) power generation system for the space applications using a nuclear fission reactor as the heat source. This MHD system uses He/Xe mixed gas as coolant instead of alkali-metal-seeded inert gas. The interrelation between the specific heat of the coolant and the mass flow rate was examined. When the specific heat decreases due to increase of the Xe fraction, the mass flow rate must increase to keep the output power and plant efficiency constant. A regenerator efficiency of 100% and reactor output temperature of 1800 K or higher should be chosen for the highest plant efficiency of 56% and lowest specific mass of 1.4 kg/kW. This highest plant efficiency and lowest specific mass were also expected by optimizing parameters for enthalpy extraction and radiator temperature. This means achieving high plant efficiency or low specific mass gives different values for enthalpy extraction and radiator temperature. With a higher net electrical output power, lower specific mass is obtained. This explains why the present space MHD power generation system is better than other conventional space power generation systems for the high MW-range output power.

Much evidence indicates that women have a higher risk of developing Alzheimer's disease (AD) than do men. The reason for this gender difference is unclear. We hypothesize that estrogen deficiency in the brains of women with AD may be a key risk factor. In rapidly acquired postmortem brains from women with AD, we found greatly reduced estrogen levels compared with those from age- and gender-matched normal control subjects; AD and control subjects had comparably low levels of serum estrogen. We examined the onset and severity of AD pathology associated with estrogen depletion by using a gene-based approach, by crossing the estrogen-synthesizing enzyme aromatase gene knockout mice with APP23 transgenic mice, a mouse model of AD, to produce estrogen-deficient APP23 mice. Compared with APP23 transgenic control mice, estrogen-deficient APP23 mice exhibited greatly reduced brain estrogen and early-onset and increased β amyloid peptide (Aβ) deposition. These mice also exhibited increased Aβ production, and microglia cultures prepared from the brains of these mice were impaired in Aβ clearance/degradation. In contrast, ovariectomized APP23 mice exhibited plaque pathology similar to that observed in the APP23 transgenic control mice. Our results indicate that estrogen depletion in the brain may be a significant risk factor for developing AD neuropathology.

The fundamental performance of a linear Faraday type magnetohydrodynamic (MHD) accelerator under chemical and thermal equilibrium conditions is studied in this paper. Quasi-one dimensional numerical simulation is performed to characterize acceleration along the specified channel. In order to solve the set of differential equations of magnetohydrodynamics, the MacCormack scheme is employed. In this present calculation, a working gas of air-plasma, consisting of diatomic molecules of nitrogen, oxygen and hydrogen, is considered in order to actualize application of the MHD accelerator propulsion system. Numerical results show the characteristics of flow velocity, gas temperature and electrical conductivity of the MHD accelerator with the working gas of air-plasma. The computations are compared with numerical simulation results using the inert gas of argon evaluated in past studies.

In order to examine the effect of estrogen on facial pain, we first compared the face-rubbing evoked by a formalin injection in the lip of aromatase-knockout (ArKO) mice, lacking endogenous estrogen production, 17 beta-estradiol-treated ArKO mice (ArKO-E2) and wild-type (WT) littermates. During the 'acute' phase of pain the time spent rubbing was similar in the three groups, whereas during the following 'interphase' and the second phase of pain, grooming was increased in ArKO mice. Estradiol-treatment restored a behaviour similar to WT group. To better understand estrogens modulation on pain processes, we examined changes in 5-HT and CGRP innervations of trigeminal nucleus caudalis (TNC) in ArKO, ArKO-E2 and WT groups sacrificed during the interphase. Whereas serotonin and CGRP immunoreactivities were comparable in WT and ArKO non-injected control groups, our data showed that 9 min after formalin injection, the density of serotoninergic terminals increased significantly in WT, but not in ArKO mice, while that of CGRP-immunoreactive fibers was lower in WT than in ArKO mice on the injected side. Estradiol-treatment only partially reversed these changes in ArKO-E2 mice. We conclude that estrogen deprivation in ArKO mice can be responsible for increased nociceptive response and that it is accompanied by transmitter changes favouring pro- over anti-nociceptive mechanisms in TNC during interphase of the formalin model. That estradiol-treatment completely reverses the behavioural abnormality suggests that estrogens absence produces chiefly functional activation-dependent changes. However, the fact that the immunohistochemical abnormalities were not totally normalized by estradiol-treatment suggested that some permanent developmental alterations may occur in ArKO mice.

Interactions between luminal epithelial cells and their surrounding microenvironment govern the normal development and function of the mammary gland. Estradiol plays a key role in abnormal intracellular signaling, which contributes to the development and progression of breast tumors. The present article summarizes the results from a microarray whole genome gene expression analysis as well as a quantitative analysis of the mRNA expression of members of the estradiol metabolic and signaling pathways in the tumors of postmenopausal breast cancer patients. The analysis of the variation in whole genome gene expression resulted in a tumor classification comprising several distinct groups with distinct expression of the estrogen receptor (ER). The parallel study on the expression of only nine mRNA transcripts of members of the estradiol pathways resulted in two main clusters, representing ER− and ER tumors. The mRNA expression of the estradiol-metabolizing enzymes did not follow the expression of the ER in all cases, leading to the recognition of several further subclasses of tumors. When the tumor classes obtained by whole genome gene expression analysis were compared with those obtained by independent quantitation of the estradiol-metabolizing enzymes, a statistically significant association between both classification groups was observed. These findings point to a possible association between development of a tumor with a particular expression profile and its capacity to synthesize estradiol as measured by the expression of the transcripts for the necessary key enzymes. Further, whole genome expression patterns were studied in 12 patients treated with anastrozole. Using significance analysis of microarrays, we identified 298 genes significantly differently expressed between partial response and progressive disease groups.

In this paper, we showed the performance of a propulsion system in space by ablation plasma produced by pulsed ion beam and its controllability. First, the fundamental study of flyer acceleration with ablation plasma produced by irradiation of an intense pulse ion beam was explained numerically. Here, we used a one-dimensional hydrodynamic model based on the stopping power taking the interaction between the flyer material and ion beam into account. Using this numerical model, a maximum flyer velocity of about 8 km/s and ablation pressure of 20 GPa could be obtained at the ion beam energy density of 4 kJ/cm2 and the pulse width of an incident ion beam of 60 ns. Moreover, our numerical results agreed well with experimental ones. From these results, we could estimate performance of the space propulsion system with ablation plasma produced by pulsed ion beam which is an impulse bit of 2000 Ns/m2 and a specific impulse of about 5000-6000 seconds at the ion beam energy density of 4 kJ/cm2 and the pulse width of an incident ion beam of 60 ns. In addition, this paper also discussed the controllability of impulse bit, and specific impulse and we finally found that changing ion beam acceleration voltage, energy density, power density, and the duration of ion beam irradiation could control both performances. Furthermore, we found that the important factors are to control the acceleration voltage and pulse width in order to improve the space propulsion performance of this system.

We found that both benzyl isothiocyanate (ITC) and phenyl ITC inhibited respiration in the mitochondria in an electrophilic reaction-dependent manner. ITC-induced mitochondrial swelling and cytochrome c release were prevented by cyclosporin A, indicating that they are mediated through the ITC moiety-dependent reaction to critical thiol groups for the opening of membrane permeability transition-dependent pores.

It is known that fusion reactions are fueled by deuterium and tritium, which are found easily in water and are known as unlimited energy resource, would release enormous energy for driving power generation system. The aim of this study is to examine and compare the plant efficiency of power generation systems using magnethydrodynamic (MHD) generator, Gas Turbine (GT), Steam Turbine (ST) and Inertial Confine-ment Fusion (ICF) reactor as heat source to generate electrical power. Three systems were considered including the MHD single system, the MHD/GT system and the MHD/ST system, and the highest plant efficiency of each system was 61.06%, 58.34% and 60.76% respectively. This result showed that the MHD single system could be expected as the most effective system because of the highest plant efficiency and the simplest system. However, it also showed that the plant efficiency decreased with the increase of the reactor outlet temperature because of the reactor's blanket limit temperature. For this reason, it was under-stood that too high a reactor outlet temperature was not desirable. The temperature of 1999K and enthalpy extraction of 33.5% would be most preferable parameters to MHD single system.

Recent results of our quasi-one-dimensional numerical simulation for the performance of an MHD accelerator under chemical and thermal equilibrium conditions are presented. For the present study, the working gas was changed to air-plasma from inert gas of argon plasma, which was studied previously to actualize the application of an MHD accelerator propulsion system. The numerical simulation confirmed the performance of MHD accelerators with segmented Faraday, Hall, and diagonal electrode connections. In order to solve the set of differential equations of magnetohydrodynamics, the MacCormack scheme is employed. The results show several parameters of MHD accelerator performance with air-plasma working gas. The calculation results are compared with previous results to clarify the effect of the difference in working gases.

During aging, the decline of neuroendocrine, endocrine, and behavioral components of reproduction ultimately leads to reproductive failure. These studies considered both neuroendocrine and behavioral aspects of reproductive aging in Japanese quail, using chronological age and reproductive status to separate animals into experimental groups. In Study I, age-related changes in the gonadotropin releasing hormone (GnRH-I) system were investigated and a sharp decrease was observed in GnRH-I concentration in the median eminence of aging animals of both sexes, whereas preoptic-lateral septal region GnRH-I concentrations declined only in aging males. Immunohistochemistry confirmed these findings since aging females retained, whereas males lost GnRH-I cells. Functional changes were assessed by in vitro incubation of parasaggittal hypothalamic slices collected from young and old inactive males and females. Results showed reduced baseline GnRH-I release and diminished response to norepinephrine (NE). Deteriorating fertility also correlated with decreased male sexual behavior and loss of aromatase immunoreactive (AROM-ir) neurons in the medial, but not lateral preoptic nucleus (POA). Sexual behavior and AROM-ir were restored with exogenous testosterone, which was associated with increased cell size in the medial POA. Comparison of cell size and number of AROM-ir cells showed that aged sexually active males had fewer, larger AROM-ir cells when compared to young males, suggesting neuroplasticity of specific neural systems and a critical role of estradiol in maintaining reproductive function.

Primary evidence for novel estrogen signaling pathways is based upon well-documented estrogenic responses not inhibited by estrogen receptor antagonists. In addition to 17beta-E2, the catechol estrogen 4-hydroxyestradiol (4OHE2) has been shown to elicit biological responses independent of classical estrogen receptors in estrogen receptor-alpha knockout (ERalphaKO) mice. Consequently, our research was designed to biochemically characterize the protein(s) that could be mediating the biological effects of catechol estrogens using enzymatically synthesized, radiolabeled 4-hydroxyestrone (4OHE1) and 4OHE2. Scatchard analyses identified a single class of high-affinity (K(d) approximately 1.6 nM), saturable cytosolic binding sites in several ERalphaKO estrogen-responsive tissues. Specific catechol estrogen binding was competitively inhibited by unlabeled catechol estrogens, but not by 17beta-E2 or the estrogen receptor antagonist ICI 182,780. Tissue distribution studies indicated significant binding differences both within and among various tissues in wild-type, ERalphaKO, and aromatase knockout female mice. Ligand metabolism experiments revealed extensive metabolism of labeled catechol estrogen, suggesting that catechol estrogen metabolites were responsible for the specific binding. Collectively, our data provide compelling evidence for the interaction of catechol estrogen metabolites with a novel binding protein that exhibits high affinity, specificity, and selective tissue distribution. The extensive biochemical characterization of this binding protein indicates that this protein may be a receptor, and thus may mediate ERalpha/beta-independent effects of catechol estrogens and their metabolites.

Endocrine disruptor chemicals are known to cause a range of abnormalities in sexual differentiation and reproduction. One mechanism underlying such effects may be via alteration of aromatase activity, which is responsible for estrogen production. A good screening system for identifying endocrine disruptors has long been desired. We have recently established a human ovarian granulosa-like tumor cell line, KGN, which possesses a relatively high level of aromatase expression and is considered a useful mammalian model for investigating the in vitro effects of various chemicals on aromatase activity. In this study we screened 55 different candidate chemicals for endocrine disruptors by assaying aromatase activity. Only benomyl, known as both a benzimidazole fungicide and a microtubule-interfering agent, was found to induce aromatase activity in association with increased levels of aromatase mRNA in KGN cells. The effect of benomyl was presumed to be mediated by its metabolite carbendazim, because it produced an effect equivalent to that of benomyl. The mechanism underlying the benomyl-induced increase in aromatase activity appears independent of the cAMP-protein kinase A pathway. Treatment with taxol, another class of microtubule-interfering agents, also caused induction of aromatase in KGN cells. Both benomyl and taxol changed KGN cell morphology, including the development of cell roundness and a disorganized network of microtubules. These results indicate that benomyl is a potential endocrine disruptor that provides a novel estrogenicity and operates through a microtubule-interfering mechanism.

In the brain, the conversion from androgen into estrogen is an important process for the differentiation of the brain function in male rodents. The aromatase is expressed in some nucleus of the brain. To assess the functional significance of the aromatase gene in development and activation of sex-specific behavior, we analyzed behavioral phenotypes of the aromatase knockout (ArKO) male mice. ArKO males obviously decreased their fertility and showed deficits in male sexual behavior including mount, intromission and ejaculation. Noncontact penile erection was not significantly affected by defect of the aromatase gene. A reduction of aggressive behavior against male intruders was also observed in ArKO males, while they tend to exhibit aggression toward estrous females during male copulatory tests. Moreover, the infanticide toward the pups was observed in the ArKO males, whereas characteristic parental behavior, but not infanticide was observed in wild-type males. These results indicate that aromatase gene expression is a critical step not only for motivational and consummatory aspects of male sexual behavior, but also for aggressive and parental behaviors in male mice.

Sexually relevant pheromonal cues are detected by the vomeronasal system which includes the posterodorsal part of the medial amygdala, the posteromedial part of the bed nucleus of the stria terminalis and the medial preoptic area. Copulatory behavior is impaired in mice lacking functional aromatase, the enzyme converting testosterone into estradiol. In this study, we used male aromatase knockout (ArKO) mice to investigate the role of aromatase in the differentiation and activation of preference for male- or female-related odorants. Moreover, using Fos immunoreactivity as a marker of neuronal activation we investigated the ability of sex-related pheromonal cues to activate the vomeronasal system. Both gonadally intact wild-type and ArKO mice preferred to investigate urine from females. The lack of estrogens did not reverse odor preferences, i.e. male ArKO mice did not show a preference for male odors. Exposure to soiled bedding from females induced Fos-protein in the posterodorsal part of the medial amygdala, in the posteromedial part of the bed nucleus of the stria terminalis, and in the periventricular part of the medial preoptic area of both the genotypes. Exposure to soiled bedding from intact males induced Fos in the posterodorsal part of the medial amygdala in wild-type mice and in the periventricular medial preoptic area in wild-type and ArKO mice. These results suggest that preference for female-related odors and the Fos-mediated activation of the vomeronasal system do not rely on estradiol. Furthermore, sensitivity to female chemosensory cues and copulatory behavior are uncoupled in this knockout model.

Aims: The pathogenesis of breast carcinoma in very elderly women is of interest, because oestrogen levels are likely to be extremely low during the development of the disease. In an effort to understand the pathogenesis of breast carcinoma in these women, this study was undertaken to compare the histological patterns and hormone receptor status of breast carcinomas arising in very elderly and younger women. Methods and results: Thirty-seven breast carcinomas from women over the age of 85 years at the time of their operation were examined histologically and compared with those from a large group of premenopausal women. The proportions of mucinous carcinoma and apocrine carcinoma were significantly greater in older women. The expression of steroid hormone receptors was studied immunohistochemically. Androgen receptor-positive carcinomas were significantly more frequent among older women, whereas progesterone receptor-positive carcinomas were significantly less frequent. There was no statistically significant difference in oestrogen receptor-α or -β expression between the tumours from both groups. Conclusion: Breast carcinomas in women over the age of 85 years have a different morphological spectrum from carcinomas in younger age groups and may have different pathogenesis mechanisms that may be more dependent on androgen and androgen receptor interaction. Differences from the results of the other studies are discussed.

Since 1987 we have been using Carpentier-Edwards porcine bioprostheses for aortic valve replacements in patients of advanced age and those with a contraindication for anticoagulation therapy. The purpose of this study was to provide insight into the midterm results of our series of patients with Carpentier-Edwards porcine bioprostheses in the aortic position. From September 1987 through June 1999, 31 patients underwent aortic valve replacement with Capentier-Edwards porcine bioprostheses. The age of the patients ranged from 21 to 89 (average, 71 ± 11 years old), and 21 patients (67.7%) were 70 years old or older. There were no operative deaths. Three hospital deaths (9.7%) and one nonhospital death (3.2%) took place. The actuarial survival rate of 31 patients was 90.3% at 5 years and 81.3% at 7 years. Valve-related complications were seen in six patients (19.4%). The postoperative Doppler peak gradient of aortic prostheses was less than 30 mm Hg in all groups, irrespective of valve size. In conclusion, the Carpentier-Edwards porcine bioprosthesis affords good durability with a low rate of valve-related complications and reoperation. Furthermore, the postoperative function of the prosthesis was reasonable in the Doppler echo studies.

Aromatase in the diencephalic neurons, the level of which increases transiently during the prenatal to neonatal period, has been suggested to be involved in control of sexual behavior and differentiation of the CNS. Effects of neurotransmitters on levels of aromatase mRNA in cultured neurons were investigated to determine factors regulating the developmental increase that occurs in level of fetal brain aromatase. The expression of aromatase in diencephalic neurons of fetal mice at embryonic day 13, cultured in vitro, was significantly affected by alpha 1-adrenergic receptor ligands. Aromatase mRNA levels were higher in neurons treated with the alpha 1-agonist phenylephrine than in control neurons, whereas prazosin, an alpha 1-antagonist, suppressed this increase, and ligands for alpha 2- or beta-adrenergic receptors did not exert any influence. The profile of alpha 1-adrenergic receptor subtypes during actual development in vivo suggested that the alpha 1B subtype is in fact responsible for the signal transduction. Substance P, cholecystokinin, neurotensin, and brain natriuretic peptide also increased the level of expression along with phorbol 12-myristate 13-acetate and dibutyrylcyclic GMP, whereas forskolin and dibutyryl-cyclic AMP caused a decrease. These data indicate that stimulation via alpha 1 (possibly alpha 1B)-adrenergic receptors, as well as receptors of specific neuropeptides, controls the expression of aromatase in embryonic day 13 diencephalic neurons through activation of protein kinase C or G. beta-Adrenergic receptors would not appear to participate in the regulation, judging from their developmental profile, although cyclic AMP might be a suppressive second messenger.

We used estrogen-deficient aromatase knock-out (ArKO) mice to determine whether estrogens contribute to the development of the brain and behavior in females. Female mice of three different genotypes [i.e., wild type (WT), heterozygous (HET), and homozygous (ArKO)] were ovariectomized in adulthood and subsequently tested for odor preferences (choice: intact male vs estrous female) in a Y-maze. When treated with testosterone, ArKO females spent significantly less time sniffing odors (both volatile and nonvolatile) from either male or female stimuli compared with WT and HET females. When given direct access to anesthetized stimulus animals or when given a choice between odor and visual cues from both stimulus animals, ArKO females continued to spend less time investigating the stimuli compared with WT and HET females. These defects in olfactory investigation of ArKO females were partially corrected with estradiol treatment in adulthood. Estradiol-treated ArKO females no longer differed from WT and HET females in the time spent investigating either nonvolatile odors or the anogenital region of anesthetized animals. However, ArKO females still investigated volatile odors and/or visual cues less than WT and HET females. Sexual receptivity was severely impaired in ArKO females after treatments with estradiol and progesterone that successfully induced receptivity in WT and HET females. Furthermore, ArKO females showed diminished levels of male sexual behaviors, whereas WT and HET females readily mounted an estrous female. Together, these findings demonstrate that estrogen is required for normal female development. The concept that the female brain develops in the absence of any hormonal stimulation should therefore be reconsidered.

The role of estrogen in the expression and induction of hepatic Cyp2b and Cyp3a isoforms was studied using mice [Ar (-/-) mice] lacking aromatase, a key enzyme for estrogen biosynthesis. The expression of P450s was determined by reverse transcription-polymerase chain reaction, immunoblotting, and measuring testosterone 6beta- and 16alpha-hydroxylase activity as markers. Basic expression of Cyp3a11 mRNA and protein was seen in both sexes of Ar (+/+) mice. Disruption of the aromatase gene caused an increase in the expression of Cyp3a11 protein, although the mRNA level remained unchanged. Female-specific Cyp3a41 disappeared in Ar (-/-) mice, and this could not be reversed by administration of exogenous beta-estradiol to adult knockout mice. The constitutive expression of female-specific Cyp2b9 also disappeared on disrupting the aromatase gene. However, in clear contrast to Cyp3a41, some individual Ar (-/-) mice exhibited expression of this form following treatment with exogenous beta-estradiol. Disruption of the aromatase gene had no effect on PB-mediated induction of Cyp2b10 or on the noninducible nature of Cyp2b9, Cyp3a11, and Cyp3a41. These results suggest that (1) Cyp3a11 is suppressed by estrogen; (2) the expression of female-specific Cyp3a41 is programmed by neonatal and/or infantile exposure to estrogen; (3) maintenance of the expression of female-specific Cyp2b9 requires estrogen in adults; and (4) endogenous estrogen plays little, if any, role in the mechanism by which PB induces Cyp2b10.

To study luteal function in the late gestational period of Phocidae (seals), we analyzed the localization of steroidogenic enzymes (P450scc, 3betaHSD and P450arom) and prolactin receptors in the corpora lutea of pregnant spotted seals (Larga seal; Phoca largha) immunohistochemically. P450scc, 3betaHSD and prolactin receptors were present in all luteal cells of each corpus luteum, and most luteal cells were immunostained for P450arom. Although we analyzed only two specimens, P450scc, 3betaHSD and prolactin receptors were negatively immunostained in the placentae. P450arom was present in the syncytiotrophoblast of placentae. These findings suggest that 1) the corpus luteum of the spotted seal synthesizes pregnenolone, progesterone and estrogen during late gestational period, 2) the placenta of this species do not possess the capacity to synthesize progesterone, and 3) like other terrestrial carnivores, this species requires prolactin to maintain the corpus luteum during pregnancy. These characteristics support the recent classification of family Phocidae in the order Carnivora, and suggest a relationship between prolactin and reproductive failure during the post-implantation period in pinnipeds.

Until recently, it has been difficult to identify the exact location of aromatase containing cells in the brain. The development of new antibodies has provided a sensitive tool to analyze the distribution of aromatase immunoreactive (ARO-ir) material at a cellular level of resolution. In the present study we examined, for the first time, the distribution of ARO-ir cells in the brain of a reptile, the red-sided garter snake, at the beginning of the winter dormancy. ARO-ir cells were found at all rostro-caudal levels in the red-sided garter snake brain. Although weakly stained cells were distributed throughout the brain, more intensely immunoreactive cells were primarily concentrated in the preoptic area, anterior hypothalamus, septum and nucleus sphericus. Although androgens are elevated upon emergence from hibernation in the male red-sided garter snake, initiation of courtship behavior appears to be independent of direct androgen control. To date, the only known stimulus found to initiate courtship is a period of low temperature dormancy followed by exposure to warm temperatures. Circumstantial data, however, suggest an indirect role in the activation of male copulatory behavior for estrogenic metabolites of testosterone produced in the brain by aromatization during the winter dormancy. This study provides the first documentation of the distribution of ARO-ir cells in a reptilian species and demonstrates that while the aromatase enzyme occurs in most regions of the brain, the ARO-ir cells that appear to contain the highest concentration of enzyme are clustered in brain areas classically associated with the control of courtship behavior and mating in vertebrates. These data are consistent with the idea that estrogens locally produced in the brain may participate in some way to the activation of sexual behavior in this species also. This notion should now be experimentally tested by analyzing annual changes in aromatase activity and immunoreactivity and assessing the effects of pharmacological blockade of the enzyme activity at different times of the year.

A method of simulating ink-particle flight for industrial, continuous inkjet printers (CIJPs) was developed to clarify the factors that influence print distortion. Print distortion is produced by aerodynamic and electric interference between the ink-particles flying from the nozzle onto the print target. The necessary functions to do this, such as the calculation of electrostatic force in the electric field between the electrodes, Coulomb's force from other charged ink-particles, and the drag force in the inkjet stream for many flying ink-particles were added to a Lagrangian method in the software to analyze the fluid dynamics that was used in the simulations. The trajectories of the ink particles flying from the nozzle onto the print target and the air flow caused by them were simultaneously calculated in the simulations. The results from simulations for the velocities and trajectories of the flying ink particles were compared with the experimental ones obtained with a high-speed camera. These simulation results were in good agreement with the experimental ones, and the developed simulation helps to clarify the factors that influence print distortion and to create algorithms that decrease it.

In space, radiation dose to crew increases in proportion to a increase of flight-time. High radiation dose to human have an influence on human health. Therefore, propulsion system that can minimize in-flight time is required. In the present study, to minimize in-flight time, nuclear electric propulsion system (NEP system) is suggested for human exploration to Mars. NEP system consists of CCMHD power generation system driven by nuclear fission reactor (NFR) providing electric power to the propulsion system and the variable specific impulse magneto-plasma rocket (VASIMR). In this study, modeling of power plant for NEP system and system analysis of it is carried out. Then Parameter are changed, the outlet temperature of NFR, the radiator temperature and the enthalpy extraction of MHD generator, in order to know how to minimize specific mass In the outlet temperature of NFR change, specific mass of NEP system decreases with an increase of outlet temperature of NFR. In the radiator temperature change, specific mass of NEP system have minimum point in radiator temperature. In the enthalpy extraction of MHD generator, specific mass of NEP system have minimum point in enthalpy extraction. Specific mass of NEP system less than ] / [ 2 kWe kg system   could be expected.