Discovery of a Long-duration Superflare on a Young Solar-type Star EK Draconis with Nearly Similar Time Evolution for H alpha and White-light Emissions

Young solar-type stars are known to show frequent "superflares, " which may severely influence the habitable worlds on young planets via intense radiation and coronal mass ejections. Here we report an optical spectroscopic and photometric observation of a long-duration superflare on the young solar-type star EK Draconis (50-120 Myr age) with the Seimei telescope and Transiting Exoplanet Survey Satellite. The flare energy 2.6 x 10³⁴ erg and white-light flare duration 2.2 hr are much larger than those of the largest solar flares, and this is the largest superflare on a solar-type star ever detected by optical spectroscopy. The H alpha emission profile shows no significant line asymmetry, meaning no signature of a filament eruption, unlike the only previous detection of a superflare on this star. Also, it did not show significant line broadening, indicating that the nonthermal heating at the flare footpoints is not essential or that the footpoints are behind the limb. The time evolution and duration of the H alpha flare are surprisingly almost the same as those of the white-light flare, which is different from general M-dwarf (super-)flares and solar flares. This unexpected time evolution may suggest that different radiation mechanisms than general solar flares are predominant, such as: (1) radiation from (off-limb) flare loops and (2) re-radiation via radiative back-warming, in both of which the cooling timescales of flare loops could determine the timescales of H alpha and white light

Efficacy of glutathione for the treatment of nonalcoholic fatty liver disease: an open-label, single-arm, multicenter, pilot study

Background: Glutathione plays crucial roles in the detoxification and antioxidant systems of cells and has been used to treat acute poisoning and chronic liver diseases by intravenous injection. This is a first study examining the therapeutic effects of oral administration of glutathione in patients with nonalcoholic fatty liver disease (NAFLD). Methods: The study was an open label, single arm, multicenter, pilot trial. Thirty-four NAFLD patients diagnosed using ultrasonography were prospectively evaluated. All patients first underwent intervention to improve their lifestyle habits (diet and exercise) for 3 months, followed by treatment with glutathione (300 mg/day) for 4 months. We evaluated their clinical parameters before and after glutathione treatment. We also quantified liver fat and fibrosis using vibration-controlled transient elastography. The primary outcome of the study was the change in alanine aminotransferase (ALT) levels. Results: Twenty-nine patients finished the protocol. ALT levels significantly decreased following treatment with glutathione for 4 months. In addition, triglycerides, non-esterified fatty acids, and ferritin levels also decreased with glutathione treatment. Following dichotomization of ALT responders based on a median 12.9% decrease from baseline, we found that ALT responders were younger in age and did not have severe diabetes compared with ALT non-responders. The controlled attenuation parameter also decreased in ALT responders. Conclusions: This pilot study demonstrates the potential therapeutic effects of oral administration of glutathione in practical dose for patients with NAFLD. Large-scale clinical trials are needed to verify its efficacy. Trial registration: UMIN000011118 (date of registration: July 4, 2013)

Probable detection of an eruptive filament from a superflare on a solar-type star

太陽型星のスーパーフレアから噴出する巨大フィラメントを初検出 --昔の、そして今の惑星環境や文明に与える脅威--. 京都大学プレスリリース. 2021-12-10.Solar flares are often accompanied by filament/prominence eruptions (~10⁴ K and ~10¹⁰⁻¹¹ cm⁻³), sometimes leading to coronal mass ejections that directly affect the Earth’s environment. ‘Superflares’ are found on some active solar-type (G-type main-sequence) stars, but the filament eruption–coronal mass ejection association has not been established. Here we show that our optical spectroscopic observation of the young solar-type star EK Draconis reveals evidence for a stellar filament eruption associated with a superflare. This superflare emitted a radiated energy of 2.0 × 10³³ erg, and a blueshifted hydrogen absorption component with a high velocity of −510 km s⁻¹ was observed shortly afterwards. The temporal changes in the spectra strongly resemble those of solar filament eruptions. Comparing this eruption with solar filament eruptions in terms of the length scale and velocity strongly suggests that a stellar coronal mass ejection occurred. The erupted filament mass of 1.1 × 10¹⁸ g is ten times larger than those of the largest solar coronal mass ejections. The massive filament eruption and an associated coronal mass ejection provide the opportunity to evaluate how they affect the environment of young exoplanets/the young Earth6 and stellar mass/angular momentum evolution

Efficacy of pegylated interferon plus ribavirin in combination with corticosteroid for two cases of combined hepatitis C and autoimmune hepatitis

The treatment strategy for cases of combined autoimmune hepatitis (AIH) and chronic hepatitis C (CHC) has not yet been established. A 47-year-old woman and a 53-year-old-woman were hospitalized for treatment of CHC. Ultrasonography and histological findings revealed that their liver was not cirrhotic but did have chronic damage. The histological findings of both patients were suggestive of AIH. The patients were systematically treated with pegylated interferon-alpha 2b plus ribavirin which was preceded by and combined with corticosteroid (CS), and showed sustained virological responses and normal liver function. Although these two patients with combined AIH and CHC were successfully treated with this regimen, careful attention to exacerbation of hepatic inflammation is needed because hepatitis C viral load was increased due to immunosuppression during CS treatment

Trends in hepatocellular carcinoma incident cases in Japan between 1996 and 2019

We examined the epidemiological trends, including the distribution of sex, age, and disease etiology, in HCC incident cases, over 24 years. Data of 20,547 HCC patients (1996–2019) were analyzed in this prospective study. We divided the study period into four 6-yearly quarters. HCC etiology was categorized as hepatitis B virus (HBV) infection, HBV + hepatitis C virus (HCV) infection, HCV infection, and both negative (non-BC). The incident cases of HCC per quarter of the study period were 4311 (21.0%), 5505 (26.8%), 5776 (28.1%), and 4955 (24.1%), sequentially. Overall, 14,020 (68.2%) patients were male. The number of HCC cases in patients < 60 years, 60–69 years, 70–79 years, and ≥ 80 years were 3711 (18.1%), 6652 (32.4%), 7448 (36.2%), and 2736 (13.3%), respectively. The average age of newly-diagnosed patients increased in each quarter. HCC was associated with HBV, HBV + HCV, and HCV infections and non-BC in 2997 (14.6%), 187 (0.9%), and 12,019 (58.5%), and 5344 (26.0%) cases, respectively. The number of HCV-associated cases decreased in each quarter, while that of non-BC-associated cases increased. HCC incident cases tend to increase in the elderly and in non-BC patients; in contrast, HCC incident cases due to HCV tend to decrease

Occupational risk factors for Parkinson's disease: a case-control study in Japan

<p>Abstract</p> <p>Background</p> <p>The evidence for associations between occupational factors and the risk of Parkinson's disease (PD) is inconsistent. We assessed the risk of PD associated with various occupational factors in Japan.</p> <p>Methods</p> <p>We examined 249 cases within 6 years of onset of PD. Control subjects were 369 inpatients and outpatients without neurodegenerative disease. Information on occupational factors was obtained from a self-administered questionnaire. Relative risks of PD were estimated using odds ratios (ORs) and 95% confidence intervals (CIs) based on logistic regression. Adjustments were made for gender, age, region of residence, educational level, and pack-years of smoking.</p> <p>Results</p> <p>Working in a professional or technical occupation tended to be inversely related to the risk of PD: adjusted OR was 0.59 (95% CI: 0.32-1.06, <it>P </it>= 0.08). According to a stratified analysis by gender, the decreased risk of PD for persons in professional or technical occupations was statistically significant only for men. Adjusted ORs for a professional or technical occupation among men and women were 0.22 (95% CI: 0.06-0.67) and 0.99 (0.47-2.07), respectively, and significant interaction was observed (<it>P </it>= 0.048 for homogeneity of OR). In contrast, risk estimates for protective service occupations and transport or communications were increased, although the results were not statistically significant: adjusted ORs were 2.73 (95% CI: 0.56-14.86) and 1.74 (95% CI: 0.65-4.74), respectively. No statistical significance was seen in data concerning exposure to occupational agents and the risk of PD, although roughly a 2-fold increase in OR was observed for workers exposed to stone or sand.</p> <p>Conclusion</p> <p>The results of our study suggest that occupational factors do not play a substantial etiologic role in this population. However, among men, professional or technical occupations may decrease the risk of PD.</p

Alcohol drinking and risk of Parkinson's disease: a case-control study in Japan

<p>Abstract</p> <p>Background</p> <p>Although some epidemiologic studies found inverse associations between alcohol drinking and Parkinson's disease (PD), the majority of studies found no such significant associations. Additionally, there is only limited research into the possible interactions of alcohol intake with aldehyde dehydrogenase (ALDH) 2 activity with respect to PD risk. We examined the relationship between alcohol intake and PD among Japanese subjects using data from a case-control study.</p> <p>Methods</p> <p>From 214 cases within 6 years of PD onset and 327 controls without neurodegenerative disease, we collected information on "peak", as opposed to average, alcohol drinking frequency and peak drinking amounts during a subject's lifetime. Alcohol flushing status was evaluated via questions, as a means of detecting inactive ALHD2. The multivariate model included adjustments for sex, age, region of residence, smoking, years of education, body mass index, alcohol flushing status, presence of selected medication histories, and several dietary factors.</p> <p>Results</p> <p>Alcohol intake during peak drinking periods, regardless of frequency or amount, was not associated with PD. However, when we assessed daily ethanol intake separately for each type of alcohol, only Japanese sake (rice wine) was significantly associated with PD (adjusted odds ratio of ≥66.0 g ethanol per day: 3.39, 95% confidence interval: 1.10-11.0, <it>P </it>for trend = 0.001). There was no significant interaction of alcohol intake with flushing status in relation to PD risk.</p> <p>Conclusions</p> <p>We did not find significant associations between alcohol intake and PD, except for the daily amount of Japanese sake. Effect modifications by alcohol flushing status were not observed.</p

BMP4 induction of trophoblast from mouse embryonic stem cells in defined culture conditions on laminin

Because mouse embryonic stem cells (mESCs) do not contribute to the formation of extraembryonic placenta when they are injected into blastocysts, it is believed that mESCs do not differentiate into trophoblast whereas human embryonic stem cells (hESCs) can express trophoblast markers when exposed to bone morphogenetic protein 4 (BMP4) in vitro. To test whether mESCs have the potential to differentiate into trophoblast, we assessed the effect of BMP4 on mESCs in a defined monolayer culture condition. The expression of trophoblast-specific transcription factors such as Cdx2, Dlx3, Esx1, Gata3, Hand1, Mash2, and Plx1 was specifically upregulated in the BMP4-treated differentiated cells, and these cells expressed trophoblast markers. These results suggest that BMP4 treatment in defined culture conditions enabled mESCs to differentiate into trophoblast. This differentiation was inhibited by serum or leukemia inhibitory factor, which are generally used for mESC culture. In addition, we studied the mechanism underlying BMP4-directed mESC differentiation into trophoblast. Our results showed that BMP4 activates the Smad pathway in mESCs inducing Cdx2 expression, which plays a crucial role in trophoblast differentiation, through the binding of Smad protein to the Cdx2 genomic enhancer sequence. Our findings imply that there is a common molecular mechanism underlying hESC and mESC differentiation into trophoblast