83 research outputs found
Magnetohydrodynamic Simulations of A Rotating Massive Star Collapsing to A Black Hole
We perform two-dimensional, axisymmetric, magnetohydrodynamic simulations of
the collapse of a rotating star of 40 Msun and in the light of the collapsar
model of gamma-ray burst. Considering two distributions of angular momentum, up
to \sim 10^{17} cm^2/s, and the uniform vertical magnetic field, we investigate
the formation of an accretion disk around a black hole and the jet production
near the hole. After material reaches to the black hole with the high angular
momentum, the disk is formed inside a surface of weak shock. The disk becomes
in a quasi-steady state for stars whose magnetic field is less than 10^{10} G
before the collapse. We find that the jet can be driven by the magnetic fields
even if the central core does not rotate as rapidly as previously assumed and
outer layers of the star has sufficiently high angular momentum. The magnetic
fields are chiefly amplified inside the disk due to the compression and the
wrapping of the field. The fields inside the disk propagate to the polar region
along the inner boundary near the black hole through the Alfv{\'e}n wave, and
eventually drive the jet. The quasi-steady disk is not an advection-dominated
disk but a neutrino cooling-dominated one. Mass accretion rates in the disks
are greater than 0.01 Msun/sec with large fluctuations. The disk is transparent
for neutrinos. The dense part of the disk, which locates near the hole, emits
neutrino efficiently at a constant rate of < 8 \times 10^{51} erg/s. The
neutrino luminosity is much smaller than those from supernovae after the
neutrino burst.Comment: 42 pages, accepted for publication in the Astrophysical Journal. A
paper with higher-resolution figures available at
http://www.ec.knct.ac.jp/~fujimoto/collapsar/mhd-color.pd
Explosive Nucleosynthesis in Magnetohydrodynamical Jets from Collapsars II. Heavy-Element Nucleosynthesis of s, r, p-Processes
We investigate the nucleosynthesis in a massive star of 70 M_solar with solar
metallicity in the main sequence stage. The helium core mass after hydrogen
burning corresponds to 32 M_solar. Nucleosynthesis calculations have been
performed during the stellar evolution and the jetlike supernova explosion of a
collapsar model, where the weak s-, p-, and r-processes are taken into account.
We confirm that s-elements of 60 < A < 90 are highly overproduced relative to
the solar abundances in the hydrostatic nucleosynthesis. During oxygen burning,
p-elements of A > 90 are produced via photodisintegrations of seed s-elements.
However, the produced p-elements are disintegrated in later stages except for
^{180}Ta. In the explosive nucleosynthesis, elements of 90 < A < 160 are
significantly overproduced relative to the solar values owing to the r-process.
Only heavy p-elements (N > 50) are overproduced via the p-process. Compared
with the previous study of r-process nucleosynthesis calculations in the
collapsar model of 40 M_solar by Fujimoto et al. 2007, 2008, our jet model
cannot contribute to the third peak of the solar r-elements and intermediate
p-elements. Averaging the overproduction factors over the progenitor masses
with the use of Salpeter's IMF, we suggest that the 70 M_solar star could
contribute to the solar weak s-elements of 60 < A < 90 and neutron-rich
elements of 90 < A < 160. We confirm the primary synthesis of light p-elements
in the ejected matter of high peak temperature. The ejected matter has [Sr/Eu]
\sim -0.4, which is different from that of a typical r-process-enriched star
CS22892-052 ([Sr/Eu] \sim -1). We find that Sr-Y-Zr isotopes are primarily
synthesized in the explosive nucleosynthesis in a similar process of the
primary production of light p-elements, which has been considered as one of the
sites of a lighter element primary process (LEPP).Comment: 25 pages, 13 figures, 2 tables, accepted for publication in Progress
of Theoretical Physic
R-Process Nucleosynthesis in MHD Jet Explosions of Core-Collapse Supernovae
We investigate -process nucleosynthesis during the magnetohydrodynamical
(MHD) explosion of supernova in a massive star of 13 . Contrary to
the case of the spherical explosion, jet-like explosion due to the combined
effects of the rotation and magnetic field lowers the electron fraction
significantly inside the layers above the iron core. We find that the ejected
material of low electron fraction responsible for the -process comes out
from the silicon rich layer of the presupernova model. This leads to the
production up to the third peak in the solar -process elements. We examine
whether the fission affects the -process paths by using the full nuclear
reaction network with both the spontaneous and -delayed fission
included. Moreover, we pay particular attention how the mass formula affects
the -process peaks with use of two mass formulae. It is found that both
formulae can reproduce the global abundance pattern up to the third peak though
detailed distributions are rather different. We point out that there are
variations in the -process nucleosynthesis if the MHD effects play an
important role in the supernova explosion.Comment: 19 pages with 7 figures, submitted to Ap
Recent topics of infrared effective lattice QCD
Three topics concerning infrared effective lattice QCD are discussed.
(1)Perfect lattice action of infrared SU(3) QCD and perfect operators for the
static potential are analytically given when we assume two-point monopole
interactions alone. The assumption seems to be justified from numerical
analyses of pure SU(3) QCD in maximally abelian gauge. (2)Gauge invariance of
monopole dominance can be proved theoretically if the gauge invariance of
abelian dominance is proved. The gauge invariance of monopole condensation
leads us to confinement of abelian neutral but color octet states after abelian
projection. (3)A stochastic gauge fixing method is developed to study the gauge
dependence of the Abelian projection, which interpolates between the maximally
abelian (MA) gauge and no gauge fixing. Abelian dominance for the heavy quark
potential holds even in the gauge which is far from Maximally Abelian one.Comment: LATTICE99(Poster),3 pages, LaTeX with 4 eps figure
Novel prospective umbrella-type lung cancer registry study for clarifying clinical practice patterns: CS-Lung-003 study protocol
Introduction
Conventional cancer registries are suitable for simple surveillance of cancer patients, including disease frequency and distribution, demographics, and prognosis; however, the collected data are inadequate to clarify comprehensively diverse clinical questions in daily practice.
Methods
We constructed an umbrella‐type lung cancer patient registry (CS‐Lung‐003) integrating multiple related prospective observational studies (linked studies) that reflect clinical questions about lung cancer treatment. The primary endpoint of this registry is to clarify daily clinical practice patterns in lung cancer treatment; a key inclusion criterion is pathologically diagnosed lung cancer. Under this registry, indispensable clinical items are detected in advance across all active linked studies and gathered prospectively and systematically to avoid excessive or insufficient data collection. Researchers are to input information mutually, irrespective of the relevance to each researcher's own study. Linked studies under the umbrella of the CS‐Lung‐003 registry will be updated annually with newly raised clinical questions; some linked studies will be newly created, while others will be deleted after the completion of the analysis. Enrollment began in July 2017.
Discussion
We successfully launched the umbrella‐type CS‐Lung‐003 registry. Under this single registry, researchers collaborate on patient registration and data provision for their own and other studies. Thus, the registry will produce results for multiple domains of study, providing answers to questions about lung cancer treatment raised by other researchers. Through such analysis of each linked study, this registry will contribute to the comprehensive elucidation of actual daily practice patterns in lung cancer treatment.
Key points
CS‐Lung‐003 registry directly integrates multiple linked studies created under the umbrella of this cancer registry to solve various clinical questions regarding daily practice patterns of lung cancer treatment
Hepatitis C Virus Infection Suppresses the Interferon Response in the Liver of the Human Hepatocyte Chimeric Mouse
BACKGROUND AND AIMS: Recent studies indicate that hepatitis C virus (HCV) can modulate the expression of various genes including those involved in interferon signaling, and up-regulation of interferon-stimulated genes by HCV was reported to be strongly associated with treatment outcome. To expand our understanding of the molecular mechanism underlying treatment resistance, we analyzed the direct effects of interferon and/or HCV infection under immunodeficient conditions using cDNA microarray analysis of human hepatocyte chimeric mice. METHODS: Human serum containing HCV genotype 1b was injected into human hepatocyte chimeric mice. IFN-α was administered 8 weeks after inoculation, and 6 hours later human hepatocytes in the mouse livers were collected for microarray analysis. RESULTS: HCV infection induced a more than 3-fold change in the expression of 181 genes, especially genes related to Organismal Injury and Abnormalities, such as fibrosis or injury of the liver (P = 5.90E-16∼3.66E-03). IFN administration induced more than 3-fold up-regulation in the expression of 152 genes. Marked induction was observed in the anti-fibrotic chemokines such as CXCL9, suggesting that IFN treatment might lead not only to HCV eradication but also prevention and repair of liver fibrosis. HCV infection appeared to suppress interferon signaling via significant reduction in interferon-induced gene expression in several genes of the IFN signaling pathway, including Mx1, STAT1, and several members of the CXCL and IFI families (P = 6.0E-12). Genes associated with Antimicrobial Response and Inflammatory Response were also significantly repressed (P = 5.22×10(-10)∼1.95×10(-2)). CONCLUSIONS: These results provide molecular insights into possible mechanisms used by HCV to evade innate immune responses, as well as novel therapeutic targets and a potential new indication for interferon therapy
The whole blood transcriptional regulation landscape in 465 COVID-19 infected samples from Japan COVID-19 Task Force
「コロナ制圧タスクフォース」COVID-19患者由来の血液細胞における遺伝子発現の網羅的解析 --重症度に応じた遺伝子発現の変化には、ヒトゲノム配列の個人差が影響する--. 京都大学プレスリリース. 2022-08-23.Coronavirus disease 2019 (COVID-19) is a recently-emerged infectious disease that has caused millions of deaths, where comprehensive understanding of disease mechanisms is still unestablished. In particular, studies of gene expression dynamics and regulation landscape in COVID-19 infected individuals are limited. Here, we report on a thorough analysis of whole blood RNA-seq data from 465 genotyped samples from the Japan COVID-19 Task Force, including 359 severe and 106 non-severe COVID-19 cases. We discover 1169 putative causal expression quantitative trait loci (eQTLs) including 34 possible colocalizations with biobank fine-mapping results of hematopoietic traits in a Japanese population, 1549 putative causal splice QTLs (sQTLs; e.g. two independent sQTLs at TOR1AIP1), as well as biologically interpretable trans-eQTL examples (e.g., REST and STING1), all fine-mapped at single variant resolution. We perform differential gene expression analysis to elucidate 198 genes with increased expression in severe COVID-19 cases and enriched for innate immune-related functions. Finally, we evaluate the limited but non-zero effect of COVID-19 phenotype on eQTL discovery, and highlight the presence of COVID-19 severity-interaction eQTLs (ieQTLs; e.g., CLEC4C and MYBL2). Our study provides a comprehensive catalog of whole blood regulatory variants in Japanese, as well as a reference for transcriptional landscapes in response to COVID-19 infection
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