586 research outputs found
Explosive nucleosynthesis in the neutrino-driven aspherical supernova explosion of a non-rotating 15 star with solar metallicity
We investigate explosive nucleosynthesis in a non-rotating 15 star
with solar metallicity that explodes by a neutrino-heating supernova (SN)
mechanism aided by both standing accretion shock instability (SASI) and
convection. To trigger explosions in our two-dimensional hydrodynamic
simulations, we approximate the neutrino transport with a simple light-bulb
scheme and systematically change the neutrino fluxes emitted from the
protoneutron star. By a post-processing calculation, we evaluate abundances and
masses of the SN ejecta for nuclei with the mass number employing a
large nuclear reaction network. Aspherical abundance distributions, which are
observed in nearby core-collapse SN remnants, are obtained for the non-rotating
spherically-symmetric progenitor, due to the growth of low-mode SASI. Abundance
pattern of the supernova ejecta is similar to that of the solar system for
models whose masses ranges (0.4-0.5) \Ms of the ejecta from the inner region
(\le 10,000\km) of the precollapse core. For the models, the explosion
energies and the \nuc{Ni}{56} masses are and
(0.05-0.06) \Ms, respectively; their estimated baryonic masses of the neutron
star are comparable to the ones observed in neutron-star binaries. These
findings may have little uncertainty because most of the ejecta is composed by
matter that is heated via the shock wave and has relatively definite
abundances. The abundance ratios for Ne, Mg, Si and Fe observed in Cygnus loop
are well reproduced with the SN ejecta from an inner region of the 15\Ms
progenitor.Comment: 15 pages, 1 table, 17 figures, accepted for publication in
Astrophyscal Journa
Anti-viral actions and viral dynamics in the early phase of three different regimens of interferon treatment for chronic hepatitis C: differences between the twice-daily administration of interferon-beta treatment and the combination therapy with interferon-alpha plus ribavirin.
To improve the efficacy of interferon (IFN) treatment for chronic hepatitis C, we have proposed the twice-daily administration of IFN-beta as a promising induction therapy. In this study, we demonstrated differences between the clearance of circulating HCV-RNA and the induction of anti-viral actions during the first 2 weeks of treatment. Nine patients with a high viral load and genotype 1b were randomly assigned to 3 groups: group A received 3MU of IFN-beta twice a day at intervals of 5 and 19 h; group B received 3MU of IFN-beta twice a day at intervals of 10 and 14 h; group C received 6MU of IFN-alpha once a day with ribavirin. The expression of OAS2, PKR, and MxA in peripheral blood mononuclear cells (PBMCs) were quantified by real-time polymerase chain reaction method. The viral clearance showed a bi-phasic pattern, and those in the second phase of groups A and B were significantly steeper than that of group C. The peak level of OAS2 during the first phase was correlated with the first phase decay. The MxA expression tended to be higher in group A and B than in group C. The expression of these 3 proteins tended to decrease at day 6 in group C, but increase in groups A and B. These might make differences in the viral decay during the second phase</p
Development of a Real time Evaluation System for Microteaching
We have developed an evaluation system for microteaching. Unlike conventional evaluation methods using paper medium, our system enables evaluation comments to be inputted in real time. In addition, our system enables evaluation comments to be displayed using a video while microteaching. As a result, an evaluator is able to input a comment while watching the teaching practice and the student is able to check the comments while watching the video
Syringocystadenocarcinoma Papilliferum: A Case Report
Syringocystadenocarcinoma papilliferum (SCACP) is a rare form of adenocarcinoma of the skin. This is the malignant counterpart of syringocystadenoma papilliferum (SCAP) and usually develops on the scalp in a long-standing lesion identified clinically as SCAP. We describe a 65-yr-old Korean man with a nodule on the right supra-pubic area with a 2-yr duration. Histologically this tumor had a similar overall configuration as in SCAP, but the tumor was asymmetric and poorly circumscribed, extending into the deep dermis and showed cytologic atypia. The tumor cells showed positive reaction to GCDFP-15, but negative reaction to CEA and HMFG-1. We established the diagnosis of SCACP in the patient, and a wide excision was performed to remove the tumor. The patient has been well without relapse or metastasis for 2 yr
The protective effect of CD40 ligandāCD40 signalling is limited during the early phase of Plasmodium infection
AbstractĪ³Ī“ T cells are essential for eliminating Plasmodium berghei XAT. Because administration of the agonistic anti-CD40 antibody can induce elimination of P. berghei XAT parasites in Ī³Ī“ T cell-deficient mice, we considered that Ī³Ī“ T cells might activate dendritic cells via CD40 signalling during infection. Here we report that administration of the anti-CD40 antibody to Ī³Ī“ T cell-deficient mice 3ā10days post-P. berghei XAT infection could eliminate the parasites. Our data suggest that dendritic cell activation via Ī³Ī“ T cells expressing CD40 ligand is critical during the early phase of infection
Genomic characterization of antibiotic resistanceāencoding genes in clinical isolates of Vibrio cholerae nonāO1/nonāO139 strains from Kolkata, India: generation of novel types of genomic islands containing plural antibiotic resistance genes
NonāO1/nonāO139 nontoxigenic Vibrio cholerae associated with choleraālike diarrhea has been reported in Kolkata, India. However, the property involved in the pathogenicity of these strains has remained unclear. The character of 25 nonāO1/nonāO139 nontoxigenic V. cholerae isolated during 8 years from 2007 to 2014 in Kolkata was examined. Determination of the serogroup showed that the serogroups O6, O10, O35, O36, O39, and O70 were represented by two strains in each serogroup, and the remaining isolates belonged to different serogroups. To clarify the character of antibiotic resistance of these isolates, an antibiotic resistance test and the gene analysis were performed. According to antimicrobial drug susceptibility testing, 13 strains were classified as drug resistant. Among them, 10 strains were quinolone resistant and 6 of the 13 strains were resistant to more than three antibiotics. To define the genetic background of the antibiotic character of these strains, wholeāgenome sequences of these strains were determined. From the analysis of these sequences, it becomes clear that all quinolone resistance isolates have mutations in quinolone resistanceādetermining regions. Further research on the genome sequence showed that four strains possess Class 1 integrons in their genomes, and that three of the four integrons are found to be located in their genomic islands. These genomic islands are novel types. This indicates that various integrons containing drug resistance genes are spreading among V. cholerae nonāO1/nonāO139 strains through the action of newly generated genomic islands
Virulence of Cholera Toxin Gene-Positive Vibrio cholerae Non-O1/non-O139 Strains Isolated From Environmental Water in Kolkata, India
Cholera toxin (CT)-producing Vibrio cholerae O1 and O139 cause acute diarrheal disease and are proven etiological agents of cholera epidemics and pandemics. On the other hand, V. cholerae non-O1/non-O139 are designated as non-agglutinable (NAG) vibrios and are not associated with epidemic cholera. The majority of NAG vibrios do not possess the gene for CT (ctx). In this study, we isolated three NAG strains (strains No. 1, 2, and 3) with ctx from pond water in Kolkata, India, and examined their pathogenic properties. The enterotoxicity of the three NAG strains in vivo was examined using the rabbit ileal intestinal loop test. Strain No. 1 induced the accumulation of fluid in the loop, and the volume of fluid was reduced by simultaneous administration of anti-CT antiserum into the loop. The volume of fluid in the loop caused by strains No. 2 and 3 was small and undetectable, respectively. Then, we cultured these three strains in liquid medium in vitro at two temperatures, 25 degrees C and 37 degrees C, and examined the amount of CT accumulated in the culture supernatant. CT was accumulated in the culture supernatant of strain No.1 when the strain was cultured at 25 degrees C, but that was low when cultured at 37 degrees C. The CT amount accumulated in the culture supernatants of the No. 2 and No. 3 strains was extremely low at both temperature under culture conditions examined. In order to clarify the virulence properties of these strains, genome sequences of the three strains were analyzed. The analysis showed that there was no noticeable difference among three isolates both in the genes for virulence factors and regulatory genes of ctx. However, vibrio seventh pandemic island-II (VSP-II) was retained in strain No. 1, but not in strains No. 2 or 3. Furthermore, it was revealed that the genotype of the B subunit of CT in strain No. 1 was type 1 and those of strains No. 2 and 3 were type 8. Histopathological examination showed the disappearance of villi in intestinal tissue exposed to strain No. 1. In addition, fluid accumulated in the loop due to the action of strain No. 1 had hemolytic activity. This indicated that strain No. 1 may possesses virulence factors to induce severe syndrome when the strain infects humans, and that some strains of NAG vibrio inhabiting pond water in Kolkata have already acquired virulence, which can cause illness in humans. There is a possibility that these virulent NAG vibrios, which have acquired genes encoding factors involved in virulence of V. cholerae O1, may emerge in various parts of the world and cause epidemics in the future
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