89 research outputs found

    Comparative study of the inial spikes of SGR giant flares in 1998 and 2004 observed with GEOTAIL: Do magnetospheric instabilities trigger large scale fracturing of magnetar's crust?

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    We present the unsaturated peak profile of SGR 1900+14 giant flare on 1998 August 27. This was obtained by particle counters of the Low Energy Particle instrument onboard the GEOTAIL spacecraft. The observed peak profile revealed four characteristic structures: initial steep rise, intermediate rise to the peak, exponential decay and small hump in the decay phase. From this light curve, we found that the isotropic peak luminosity was 2.3×10462.3\times10^{46} erg s1^{-1} and the total energy was 4.3×10444.3 \times 10^{44} erg s1^{-1} (EE\gtrsim 50 keV), assuming that the distance to SGR 1900+14 is 15 kpc and that the spectrum is optically thin thermal bremsstrahlung with kT=kT = 240 keV. These are consistent with the previously reported lower limits derived from Ulysses and Konus-Wind observations. A comparative study of the initial spikes of SGR 1900+14 giant flare in 1998 and SGR 1806-20 in 2004 is also presented. The timescale of the initial steep rise shows the magnetospheric origin, while the timescale of the intermediate rise to the peak indicates that it originates from the crustal fracturing. Finally, we argue that the four structures and their corresponding timescales provide a clue to identify extragalactic SGR giant flares among short GRBs.Comment: 12 pages, 3 figures, accepted by ApJ

    Berberine improved experimental chronic colitis by regulating interferon-gamma- and IL-17A-producing lamina propria CD4(+) T cells through AMPK activation

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    The herbal medicine berberine (BBR) has been recently shown to be an AMP-activated protein kinase (AMPK) productive activator with various properties that induce anti-inflammatory responses. We investigated the effects of BBR on the mechanisms of mucosal CD4+T cell activation in vitro and on the inflammatory responses in T cell transfer mouse models of inflammatory bowel disease (IBD). We examined the favorable effects of BBR in vitro, using lamina propria (LP) CD4+ T cells in T cell transfer IBD models in which SCID mice had been injected with CD4+CD45RBhigh T cells. BBR suppressed the frequency of IFN-γ- and Il-17A-producing LP CD4+ T cells. This effect was found to be regulated by AMPK activation possibly induced by oxidative phosphorylation inhibition. We then examined the effects of BBR on the same IBD models in vivo. BBR-fed mice showed AMPK activation in the LPCD4+ T cells and an improvement of colitis. Our study newly showed that the BBR-induced AMPK activation of mucosal CD4+ T cells resulted in an improvement of IBD and underscored the importance of AMPK activity in colonic inflammation

    Therapeutic effect of aged garlic extract on gingivitis in dogs

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    Periodontal disease is one of the most common dental health problems in dogs. Clinical studies in humans have shown that aged garlic extract (AGE), which contains stable and water-soluble sulfur-containing bioactive compounds, improves the symptoms of periodontal diseases. Our previous study demonstrated that oral administration of AGE in healthy Beagle dogs at 90 mg/kg/day for 12 weeks had no adverse effects such as hemolytic anemia, which is well known to occur as a result of ingestion of Allium species, including onions and garlic, in dogs. However, the therapeutic potential of AGE in canine periodontal disease remains unclear. Accordingly, we investigated the therapeutic effects of AGE in Beagle dogs with mild gingivitis. Feeding 18 mg/kg/day of AGE for 8 weeks resulted in the improvement of gingival index score, level of volatile sulfur compounds in exhaled air, and enzyme activity of periodontal pathogens without any adverse effects on clinical signs and hematological and serum biochemical parameters. Moreover, AGE increased the concentration of salivary cathelicidin, an antimicrobial peptide that contributes to the oral innate immune response. These results suggest that AGE could be a potential therapeutic agent for canine gingivitis

    GEOTAIL observation of the SGR1806-20 Giant Flare: The first 600 ms

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    On December 27, 2004, plasma particle detectors on the GEOTAIL spacecraft detected an extremely strong signal of hard X-ray photons from the giant flare of SGR1806-20, a magnetar candidate. While practically all gamma-ray detectors on any satellites were saturated during the first ~500 ms interval after the onset, one of the particle detectors on GEOTAIL was not saturated and provided unique measurements of the hard X-ray intensity and the profile for the first 600 ms interval with 5.48 ms time resolution. After ~50 ms from the initial rapid onset, the peak photon flux (integrated above ~50 keV) reached the order of 10^7 photons sec^{-1} cm^{-2}. Assuming a blackbody spectrum with kT=175 keV, we estimate the peak energy flux to be 21 erg sec^{-1} cm^{-2} and the fluence (for 0-600 ms) to be 2.4 erg cm^{-2}. The implied energy release comparable to the magnetic energy stored in a magnetar (~10^{47} erg) suggests an extremely efficient energy release mechanism.Comment: 6 pages, 2 color figures, submitted to Natur

    A genome-wide association study on meat consumption in a Japanese population : the Japan Multi-Institutional Collaborative Cohort study

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    Recent genome-wide association studies (GWAS) on the dietary habits of the Japanese population have shown that an effect rs671 allele was inversely associated with fish consumption, whereas it was directly associated with coffee consumption. Although meat is a major source of protein and fat in the diet, whether genetic factors that influence meat-eating habits in healthy populations are unknown. This study aimed to conduct a GWAS to find genetic variations that affect meat consumption in a Japanese population. We analysed GWAS data using 14 076 participants from the Japan Multi-Institutional Collaborative Cohort (J-MICC) study. We used a semi-quantitative food frequency questionnaire to estimate food intake that was validated previously. Association of the imputed variants with total meat consumption per 1000 kcal energy was performed by linear regression analysis with adjustments for age, sex, and principal component analysis components 1–10. We found that no genetic variant, including rs671, was associated with meat consumption. The previously reported single nucleotide polymorphisms that were associated with meat consumption in samples of European ancestry could not be replicated in our J-MICC data. In conclusion, significant genetic factors that affect meat consumption were not observed in a Japanese population

    Population Attributable Fraction of Smoking and Metabolic Syndrome on Cardiovascular Disease Mortality in Japan: a 15-Year Follow Up of NIPPON DATA90

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    <p>Abstract</p> <p>Background</p> <p>Smoking and metabolic syndrome are known to be related to cardiovascular diseases (CVD) risk. In Asian countries, prevalence of obesity has increased and smoking rate in men is still high. We investigated the attribution of the combination of smoking and metabolic syndrome (or obesity) to excess CVD deaths in Japan.</p> <p>Methods</p> <p>A cohort of nationwide representative Japanese samples, a total of 6650 men and women aged 30-70 at baseline without history of CVD was followed for 15 years. Multivariate-adjusted hazard ratio for CVD death according to the combination of smoking status and metabolic syndrome (or obesity) was calculated using Cox proportional hazard model. Population attributable fraction (PAF) of CVD deaths was calculated using the hazard ratios.</p> <p>Results</p> <p>During the follow-up period, 87 men and 61 women died due to CVD. The PAF component of CVD deaths in non-obese smokers was 36.8% in men and 11.3% in women, which were higher than those in obese smokers (9.1% in men and 5.2% in women). The PAF component of CVD deaths in smokers without metabolic syndrome was 40.9% in men and 11.9% in women, which were also higher than those in smokers with metabolic syndrome (7.1% in men and 3.9% in women).</p> <p>Conclusion</p> <p>Our results indicated that a large proportion of excess CVD deaths was observed in smokers without metabolic syndrome or obesity, especially in men. These findings suggest that intervention targeting on smokers, irrespective of the presence of metabolic syndrome, is still important for the prevention of CVD in Asian countries.</p

    Association between Stress-Coping Strategy and Functional Disability in the General Older Adult Population: The Takashima Study.

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    Background:Both physical and psychological factors have been associated with functional disability. However, the associations between stress-coping strategies and future functional disability remain unclear.Methods:We analyzed 2,924 participants who did not have incidence of functional disability or death within the first 3 years of the baseline survey and were aged 65 years or more at the end of follow-up. Stress-coping strategies were assessed via a self-administered questionnaire (emotional expression, emotional support seeking, positive thought, problem-solving, and disengagement) in a baseline survey from 2006 to 2014. Levels of coping strategies were classified as low, middle, and high based of frequency. Functional disability decline was followed up using the long-term-care insurance program until November 1, 2019. Functional disability decline was defined as a new long-term-care insurance program certification. Cox proportional hazards model with competing risk analysis for death was used to evaluate associations between coping strategy levels and functional disability.Results:During the follow-up period, we observed 341 cases of functional disability and 73 deaths without previous incidence of functional disability. A significant inverse association between "positive thought" and "problem-solving" and future functional disability was observed. Multivariable adjusted hazard ratios (95% confidence interval) for functional disability were 0.68 (0.51-0.92) for high levels of "positive thought" and 0.73 (0.55-0.95) for high levels of "problem-solving," compared with low levels of the coping strategies. The inverse association was stronger in men.Conclusions:Some subcomponents of stress-coping strategies might be associated with future incidence of functional disability among older adults
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