267 research outputs found

    OCTAD-S: Digital Fast Fourier Transform Spectrometers by FPGA

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    We have developed a digital fast Fourier transform (FFT) spectrometer made of an analog-to-digital converter (ADC) and a field-programmable gate array (FPGA). The base instrument has independent ADC and FPGA modules, which allow us to implement different spectrometers in a relatively easy manner. Two types of spectrometers have been instrumented, one with 4.096 GS/s sampling speed and 2048 frequency channels and the other with 2.048 GS/s sampling speed and 32768 frequency channels. The signal processing in these spectrometers has no dead time and the accumulated spectra are recorded in external media every 8 ms. A direct sampling spectroscopy up to 8 GHz is achieved by a microwave track-and-hold circuit, which can reduce the analog receiver in front of the spectrometer. Highly stable spectroscopy with a wide dynamic range was demonstrated in a series of laboratory experiments and test observations of solar radio bursts.Comment: 20 pages, 7 figures, accepted for publication in Earth, Planets and Spac

    Real-time monitor of geomagnetic field in the near-pole regions as an index of magnetospheric electric field

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    Solar wind electric field that penetrates into the magnetosphere is an important key for causes of magnetosphenc disturbances. Since PC index, produced from the variation of the magnetic field in the near-pole regions is known to be a good indicator of magnetospheric electric field, monitoring the magnetic activity in the near-pole regions in real-time is useful for nowcasting/forecasting space weather. From the comparison of horizontal components of the magnetic field data between two stations, Eureka and Thule, it is found that the correlation between these two stations are quite high except for the summer months. This result suggests that magnetic field variations in the near-pole region are uniform, and the index can be produced throughout the year using magnetic field data in the northern and southern near-pole region

    Prevalence of Exogenous Hormone Use in Japanese Women

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    Background: There have been few community-based epidemiological studies in which the prevalence of exogenous hormone use, including the use of oral contraceptives (OCs) and hormone replacement therapy (HRT), has been accurately assessed in Japan. Methods: We have been conducting repeated surveys of participants in the Japan Nurses’ Health Study (JNHS), as a nationwide prospective cohort study, since 2001. We determined the prevalence of exogenous hormone use at baseline and during a 10-year follow-up period. A total of 15,019 female nurses participated in the JNHS follow-up cohort. We determined the prevalence of OC use in 14,839 women <60 years of age at baseline and the prevalence of HRT use in 7,915 women, excluding premenopausal women, at the last time they answered a questionnaire. The duration of HRT use was estimated using the Kaplan-Meier method. Results: Six percent of the participants used OCs. The proportion of HRT users who stopped HRT before the baseline survey, the proportion of women using HRT during the follow-up period, and the proportion of all of the participants who had used HRT were 3.2%, 10.6%, and 13.8%, respectively. The median duration of HRT use was 2 years. Conclusions: The lifetime prevalences of exogenous hormone use during this prospective study conducted in Japanese nurses were 6.0% for OCs and 13.8% for HRT. The information obtained in this study will be useful for clarification of the association between exogenous estrogen exposure and estrogen-related diseases as future research

    Urinary FSH in postmenopausal women

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    The change in follicle-stimulating hormone (FSH) during the menopausal transition and associations of FSH with various diseases have been assessed by using blood samples. We examined cross-sectionally the variation of FSH levels, associations of estrone and estradiol with FSH, and associations of BMI with these hormones by using urinary samples from peri- and postmenopausal women in Japan. Of 4472 participants in the Urinary Isoflavone Concentration Survey of the Japan Nurses’ Health Study, we analyzed urinary levels of estrone, estradiol and FSH in 547 women aged from 45 to 54 years. Urinary FSH levels varied widely in postmenopausal women and the pattern of change in urinary FSH levels seems to be similar to that in blood FSH levels in previous studies. There were no significant differences in age, body mass index (BMI), estradiol, estrone and estradiol/estrone ratio among three groups according to the tertile of FSH. In postmenopausal women, there were significant associations of BMI with levels of estrone and estradiol, but there was no significant association of BMI with FSH. Studies using urinary samples will allow us to establish a study project as a large-scale population-based study to determine associations between FSH and various diseases after menopause

    Tumor Shrinkage in Response to Vitamin K2 in Hepatocellular Carcinoma with Multiple Lung Metastases: A Case Report

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    Introduction: Advanced or metastatic hepatocellular carcinoma (HCC) can be lethal because of the limited therapeutic approach such as sorafenib. Recently, Vitamin K2 (VK2) has been increasingly recognized to have anti-cancer effects for HCC in vitro and vivo. However, the direct anti-cancer effect of VK2 to HCC has not been established yet in human.Presentation of Case: We presented here a 88-year-HCC patient displayed a tumor shrinkage in response to VK2 in multiple lung metastases, indicating the possibility of VK2 as an anti-cancer agent in human. Menatetrenone, a VK2 analogue, was introduced for multiple lung metastases as a palliative treatment, and thereafter multiple lung metastases, except one lung lesion, displayed tumor shrinkage and disappeared within five months after VK2 intake. The residual one lesion continued to grow up during the intake of VK2, suggesting that the residual tumor was insensitive to VK2 represented by tumor heterogeneity. Consequently, after a radiation therapy for the residual lesion, the elevated tumor markers of all were finally decreased into normal levels, and he is still alive for 18 months after VK2 intake without elevated tumor marker levels and toxic adverse effects.Conclusion:VK2 may be a therapeutic option for advanced and metastatic HCCs without any toxic adverse

    Fe-K line probing of material around the AGN central engine with Suzaku

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    We systematically analyzed the high-quality Suzaku data of 88 Seyfert galaxies. We obtained a clear relation between the absorption column density and the equivalent width of the 6.4 keV line above 1023^{23} cm2^{-2}, suggesting a wide-ranging column density of 102324.510^{23-24.5} cm2^{-2} with a similar solid and a Fe abundance of 0.7--1.3 solar for Seyfert 2 galaxies. The EW of the 6.4 keV line for Seyfert 1 galaxies are typically 40--120 eV, suggesting the existence of Compton-thick matter like the torus with a column density of >1023>10^{23} cm2^{-2} and a solid angle of (0.150.4)4pi(0.15-0.4)*4pi, and no difference of neutral matter is visible between Seyfert 1 and 2 galaxies. An absorber with a lower column density of 10212310^{21-23} cm2^{-2} for Compton-thin Seyfert 2 galaxies is suggested to be not a torus but an interstellar medium. These constraints can be understood by the fact that the 6.4 keV line intensity ratio against the 10--50 keV flux is almost identical within a range of 2--3 in many Seyfert galaxies. Interestingly, objects exist with a low EW, 10--30 eV, of the 6.4 keV line, suggesting that those torus subtends only a small solid angle of <0.24pi<0.2*4pi. Ionized Fe-Kα\alpha emission or absorption lines are detected from several percents of AGNs. Considering the ionization state and equivalent width, emitters and absorbers of ionized Fe-K lines can be explained by the same origin, and highly ionized matter is located at the broad line region. The rapid increase in EW of the ionized Fe-K emission lines at NH>1023N_{H}>10^{23} cm2^{-2} is found, like that of the cold material. It is found that these features seem to change for brighter objects with more than several 104410^{44} erg/s such that the Fe-K line features become weak. We discuss this feature, together with the torus structure.Comment: 32 pages, 20 figures, ApJ accepte
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