太陽で起きる小規模なフレアと付随する質量放出・ジェットに関する理論的・観測的研究

京都大学新制・課程博士博士(理学)甲第24415号理博第4914号新制||理||1702(附属図書館)京都大学大学院理学研究科物理学・宇宙物理学専攻(主査)准教授 浅井 歩, 教授 一本 潔, 教授 横山 央明学位規則第4条第1項該当Doctor of ScienceKyoto UniversityDFA

Increased Plasma Levels of Platelet Factor 4 and β-thromboglobulin in Women with Recurrent Pregnancy Loss

Thrombosis in decidual vessels is one of the mechanisms of pregnancy loss. However, few studies have assessed the relation between platelet activation, which is known to cause of thrombosis, and recurrent pregnancy loss (RPL). We investigated platelet activation in women with RPL compared to controls by measuring plasma levels of platelet factor 4 (PF4) and β-thromboglobulin (βTG), and assessed correlations between PF4/βTG and coagulative risk factors associated with RPL. The study group included 135 women who had experienced two or more consecutive pregnancy losses. The control group included 28 age-matched healthy women who had never experienced pregnancy loss. PF4 and βTG plasma levels were significantly higher in the women with RPL than controls (PF4: 14.0 [8.0-20.0] vs. 9.0 [6.0-12.0] ng/ml, p=0.043; βTG: 42.0 [24.3-59.8] vs. 31.5 [26.6-36.4] ng/ml, p=0.002). There was a significant association between βTG and anti-phosphatidylethanolamine antibody immunoglobulin M (aPE IgM) (p=0.048). Among the women with RPL, 18 of those who were positive for PF4 (45%) and 18 of those who were positive for βTG (37%) were negative for all known coagulative risk factors associated with RPL. Measurements of PF4 and βTG may be important because they help identify women who are at risk of RPL

Slow Fetal Heart Rate before Miscarriage in the Early First Trimester Predicts Fetal Aneuploidy in Women with Recurrent Pregnancy Loss

Establishing whether miscarriages result from fetal aneuploidy or other factors is important for treating recurrent pregnancy loss. We examined the relationship between fetal heart rate (FHR) before miscarriage in the early first trimester and fetal karyotype, analyzing 223 pregnant women with recurrent pregnancy loss. Among the pregnancies, 110 resulted in live births regarded as normal karyotype (the Norm-group). The other 113 pregnancies ended in miscarriage, and we categorized them into groups based on fetal karyotype, determined by chorionic villus sampling: the Misc-NK (normal karyotype) group, n=35 euploid cases; the Misc-CA1 (chromosomal abnormality) group, n=18 cases of aneuploidy with trisomies 13/18/21, Turner’s syndrome, or Klinefelter’s syndrome; and the Misc-CA2 subgroup, n=60 cases of other aneuploidies excluding those in the Misc-CA1 group. We compared the groups’ regression line slopes and intercepts for FHR by an analysis of covariance. The FHRs of the Norm, Misc-NK and Misc-CA1 groups increased from 36 to 49 days after fertilization, but did not significantly differ across these groups. The Misc-CA2 group’s FHR did not increase and significantly differed from the other three groups (p<0.01). These results suggest that the absence of an increase in FHR in early pregnancy may indicate the presence of chromosomal abnormalities causing miscarriage

Thermodynamic properties of small flares in the quiet Sun observed by Hα\alpha and EUV: plasma motion of the chromosphere and time evolution of temperature/emission measure

Small flares frequently occur in the quiet Sun. Previous studies have noted that they share many common characteristics with typical solar flares in active regions. However, their similarities and differences are not fully understood, especially their thermal properties. In this study, we performed imaging spectroscopic observations in the H$\alpha$ line taken with the Solar Dynamics Doppler Imager on the Solar Magnetic Activity Research Telescope (SMART/SDDI) at the Hida Observatory and imaging observations with the Atmospheric Imaging Assembly onboard Solar Dynamics Observatory (SDO/AIA). We analysed 25 cases of small flares in the quiet Sun over the thermal energy range of $10^{24}-10^{27}\,\mathrm{erg}$, paying particular attention to their thermal properties. Our main results are as follows: (1) We observe a redshift together with line centre brightening in the H$\alpha$ line associated with more than half of the small flares. (2) We employ differential emission measure analysis using AIA multi-temperature (channel) observations to obtain the emission measure and temperature of the small flares. The results are consistent with the Shibata & Yokoyama (1999, 2002) scaling law. From the scaling law, we estimated the coronal magnetic field strength of small flares to be 5 --15 G. (3) The temporal evolution of the temperature and the density shows that the temperature peaks precede the density peaks in more than half of the events. These results suggest that chromospheric evaporations/condensations play an essential role in the thermal properties of some of the small flares in the quiet Sun, as does for large flares.Comment: 14 pages, 12 figures, accepted for publication in MNRA

Unified Relationship between Cold Plasma Ejections and Flare Energies Ranging from Solar Microflares to Giant Stellar Flares

We often find spectral signatures of chromospheric cold plasma ejections accompanied by flares in a wide range of spatial scales in the solar and stellar atmospheres. However, the relationship between physical quantities (such as mass, kinetic energy, and velocity) of cold ejecta and flare energy has not been investigated in a unified manner for the entire range of flare energies to date. This study analyzed the spectra of cold plasma ejections associated with small-scale flares and solar flares (energy $10^{25}-10^{29}\,\mathrm{erg}$) to supply smaller energy samples. We performed H$\alpha$ imaging spectroscopy observation by the Solar Dynamics Doppler Imager on the Solar Magnetic Activity Research Telescope (SMART/SDDI). We determined the physical quantities of the ejecta by cloud model fitting to the H$\alpha$ spectrum. We determined flare energy by differential emission measure analysis using Atmospheric Imaging Assembly onboard Solar Dynamics Observatory (SDO/AIA) for small-scale flares and by estimating the bolometric energy for large-scale flares. As a result, we found that the ejection mass $M$ and the total flare energy $E_{\mathrm{tot}}$ follow a relation of $M\propto E_{\mathrm{tot}}^{2/3}$. We show that the scaling law derived from a simple physical model explains the solar and stellar observations with a coronal magnetic field strength as a free parameter. We also found that the kinetic energy and velocity of the ejecta correlate with the flare energy. These results suggest a common mechanism driven by magnetic fields to cause cold plasma ejections with flares on the Sun and stars.Comment: 23 pages, 10 figures; accepted for publication in Ap

Amino acid influx via LAT1 regulates iron demand and sensitivity to PPMX-T003 of aggressive natural killer cell leukemia

Yanagiya R., Miyatake Y., Watanabe N., et al. Amino acid influx via LAT1 regulates iron demand and sensitivity to PPMX-T003 of aggressive natural killer cell leukemia. Leukemia , (2024); 10.1038/s41375-024-02296-6.Aggressive natural killer cell leukemia (ANKL) is a rare hematological malignancy with a fulminant clinical course. Our previous study revealed that ANKL cells proliferate predominantly in the liver sinusoids and strongly depend on transferrin supplementation. In addition, we demonstrated that liver-resident ANKL cells are sensitive to PPMX-T003, an anti-human transferrin receptor 1 inhibitory antibody, whereas spleen-resident ANKL cells are resistant to transferrin receptor 1 inhibition. However, the microenvironmental factors that regulate the iron dependency of ANKL cells remain unclear. In this study, we first revealed that the anti-neoplastic effect of PPMX-T003 was characterized by DNA double-strand breaks in a DNA replication-dependent manner, similar to conventional cytotoxic agents. We also found that the influx of extracellular amino acids via LAT1 stimulated sensitivity to PPMX-T003. Taken together, we discovered that the amount of extracellular amino acid influx through LAT1 was the key environmental factor determining the iron dependency of ANKL cells via adjustment of their mTOR/Myc activity, which provides a good explanation for the different sensitivity to PPMX-T003 between liver- and spleen-resident ANKL cells, as the liver sinusoid contains abundant amino acids absorbed from the gut. (Figure presented.