954 research outputs found
Mock X-ray observations of hot gas with L-Galaxies semi-analytic models of galaxy formation
We create mock X-ray observations of hot gas in galaxy clusters with a new
extension of L-Galaxies semi-analytic model of galaxy formation, which includes
the radial distribution of hot gas in each halo. Based on the model outputs, we
first build some mock light cones, then generate mock spectra with SOXS package
and derive the mock images in the light cones. Using the mock data, we simulate
the mock X-ray spectra for ROSAT all-sky survey, and compare the mock spectra
with the observational results. Then, we consider the design parameters of HUBS
mission and simulate the observation of the halo hot gas for HUBS as an
important application of our mock work. We find: (1) Our mock data match the
observations by current X-ray telescopes. (2) The survey of hot baryons in
resolved clusters by HUBS is effective below redshift 0.5, and the observations
of the emission lines in point-like sources at z>0.5 by HUBS help us understand
the hot baryons in the early universe. (3) By taking the advantage of the large
simulation box and flexibility in semi-analytic models, our mock X-ray
observations provide the opportunity to make target selection and observation
strategies for forthcoming X-ray facilities.Comment: 15 pages, 11 figures, comments welcom
Inhibitory effects of total saponins from Ilex pubescens Hook against hydrogen peroxide-induced cardiomyocyte apoptosis
Purpose: To study the protective effects of total saponins from Ilex pubescens Hook (IPTS) against cardiomyocyte apoptosis.Methods: Response surface methodology (RSM) based on Box-Benhnken Design (BBD) was carried out to optimize the extraction of IPTS. Thereafter, H9c2 cell model prepared by hydrogen peroxide (H2O2) treatment was used to investigate the effects of IPTS on cardiomyocyte apoptosis. Cell viability was determined using MTT assay, while the levels of lactate dehydrogenase (LDH), malondialdehyde (MDA), superoxide dismutase (SOD), creatine kinase (CK) and catalase (CAT) were measured as indices of oxidative stress. Expressions of proteins related to apoptosis (caspase-3, Bax and Bcl-2) were measured using Western blot assay.Results: Optimal IPTS extraction was achieved with extraction temperature of 86.6 °C, extraction time of 2.23 h and water: raw material ratio of 10.8 mL/g. IPTS extract, at doses of 200, 400, 600 and 800 Όg/mL, significantly increased the viability of H2O2-treated H9c2 cells (p < 0.05), but significantly decreased LDH and CK activities (p < 0.01). It also led to significant increases in SOD and CAT activities, and significant decreases in the levels of MDA in these cells (p < 0.01). There were significant down-regulation of the protein expressions of caspase-3 and Bax (p < 0.01) in IPTS-treated H9c2 cells, as well as significant up-regulation of Bcl-2 protein expression (p < 0.01).Conclusion: These results suggest that IPTS can protect cardiomyocytes against apoptosis via the inhibition of oxidative stress and mitochondria-induced intrinsic apoptosis.Keywords: Ilex pubescens, Total saponins, Cardiomyocytes, Apoptosis, H9c2 cell
Quantum Liouville Theory On The Riemann Sphere With Punctures
We have studied the quantum Liouville theory on the Riemann sphere with n>3
punctures. While considering the theory on the Riemann surfaces with n=4
punctures, the quantum theory near an arbitrary but fixed puncture can be
obtained via canonical quantization and an extra symmetry is explored. While
considering more than four distinguished punctures, we have found the exchange
relations of the monodromy parameters from which we can get a reasonable
quantum theory.Comment: 13 page
The hot gas distribution, X-ray luminosity and baryon budget in the L-Galaxies semi-analytic model of galaxy formation
Hot ionized gas is important in the baryon cycle of galaxies and contributes
the majority of their ``missing baryons''. Until now, most semi-analytic models
of galaxy formation have paid little attention to hot gaseous haloes and their
X-ray emission. In this paper, we adopt the one-dimensional model from Sharma
et al. instead of the isothermal sphere to describe the radial distribution of
hot gas in the L-Galaxies semi-analytic model. The hot gas halo can be divided
into two parts according to the ratio of the local thermal instability
time-scale and the free-fall time-scale: a cool core with and a stable outer halo with . We update the
prescriptions of cooling, feedback and stripping based on the new hot gas
profiles, and then reproduce several X-ray observational results, like the
radial profiles of hot gas density, and the scaling relations of X-ray
luminosity and temperature. We find: (1) Consistent with observations, flatter
density profiles in halo centers produce lower X-ray emission than an
isothermal sphere; (2) Cool core regions prone to precipitation have higher gas
temperature than the virial temperature, and a larger
ratio in smaller haloes leads to a steeper slope in the
relation; (3) The ionized gas in the unbounded reservoir and low temperature
intergalactic gas in low mass haloes could be the main components of the halo
``missing baryons''. Our model outputs can predict the observations of hot gas
in the nearby universe and produce mock surveys of baryons probed by future
X-ray telescopes.Comment: 18 pages, 15 figures, accepted for publication in MNRA
The hot gas distribution, X-ray luminosity and baryon budget in the L-Galaxies semi-analytic model of galaxy formation
© 2022 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society. This is the accepted manuscript version of an article which has been published in final form at https://doi.org/10.1093/mnras/stac3735Hot ionized gas is important in the baryon cycle of galaxies and contributes the majority of their ``missing baryons''. Until now, most semi-analytic models of galaxy formation have paid little attention to hot gaseous haloes and their X-ray emission. In this paper, we adopt the one-dimensional model from Sharma et al. instead of the isothermal sphere to describe the radial distribution of hot gas in the L-Galaxies semi-analytic model. The hot gas halo can be divided into two parts according to the ratio of the local thermal instability time-scale and the free-fall time-scale: a cool core with and a stable outer halo with . We update the prescriptions of cooling, feedback and stripping based on the new hot gas profiles, and then reproduce several X-ray observational results, like the radial profiles of hot gas density, and the scaling relations of X-ray luminosity and temperature. We find: (1) Consistent with observations, flatter density profiles in halo centers produce lower X-ray emission than an isothermal sphere; (2) Cool core regions prone to precipitation have higher gas temperature than the virial temperature, and a larger ratio in smaller haloes leads to a steeper slope in the relation; (3) The ionized gas in the unbounded reservoir and low temperature intergalactic gas in low mass haloes could be the main components of the halo ``missing baryons''. Our model outputs can predict the observations of hot gas in the nearby universe and produce mock surveys of baryons probed by future X-ray telescopes.Peer reviewe
Mass spectra of bottom-charm baryons
In this paper, we investigate the mass spectra of bottom-charm baryons
systematically, where the relativistic quark model and the infinitesimally
shifted Gaussian basis function method are employed. Our calculation shows that
the -mode appears lower in energy than the other excited modes. According
to this feature, the allowed quantum states are selected and a systematic study
of the mass spectra for () and
() families is performed. The root mean square radii and quark
radial probability density distributions of these baryons are analyzed as well.
Next, the Regge trajectories in the plane are successfully
constructed based on the mass spectra. At last, we present the structures of
the mass spectra, and analyze the difficulty and opportunity in searching for
the ground states of bottom-charm baryons in experiment.Comment: 19 pages, 9 figures, 6 tables. arXiv admin note: text overlap with
arXiv:2210.1308
Mass spectra of double-bottom baryons
Based on the relativistic quark model and the infinitesimally shifted
Gaussian basis function method, we investigate the mass spectra of double
bottom baryons systematically. In the -mode which appears lower in energy
than the other excited modes, we obtain the allowed quantum states and perform
a systematic study of the mass spectra of the and
families. We analyze the root mean square radii and quark radial probability
density distributions to deeply understand the structure of the heavy baryons.
Meanwhile, the mass spectra allow us to successfully construct the Regge
trajectories in the plane. We also predict the masses of the ground
states of double bottom baryons and discuss the differences between the
structures of our spectra and those from other theoretical methods. At last,
the shell structure of the double bottom baryon spectra is shown, from which
one could get a bird's-eye view of the mass spectra.Comment: 16 pages, 9 figures, 5 tables. arXiv admin note: text overlap with
arXiv:2207.0416
The new genetic environment of cfr on plasmid pBS-02 in a Bacillus strain
Sir,
The gene cfr, encoding a 23S rRNA methyltransferase, confers resistance to five chemically unrelated antimicrobial classes, including phenicols, lincosamides, oxazolidinones, pleuromutilins and streptogramin A (PhLOPSA), and has been observed mainly in staphylococcal isolates over the past decade.1â3 Our previous study reported a cfr-carrying plasmid, pBS-01, in a novel strain (BS-01) of a Bacillus species isolated from a pig farm in China.4 In our routine surveillance study on antimicrobial resistance in farm animals in 2010, another florfenicol and chloramphenicol-resistant Bacillus species strain (named BS-02) from swine faeces was identified. Gram staining, sequence analysis of the 16S rRNA and API 50CH testing associated with the API 20E system (bioMĂ©rieux, France) showed that BS-02 had an identical profile to that of strain BS-01, which suggested that BS-02 also belongs to a novel Bacillus species. Despite their identical profiles, more than six PFGE band differences were observed between BS-01 and BS-02 (data not shown), indicating that they belong to different clonal types of the same species
Angiotensin-converting enzyme gene 2350 G/A polymorphism and susceptibility to atrial fibrillation in Han Chinese patients with essential hypertension
OBJECTIVE: The angiotensin-converting enzyme gene is one of the most studied candidate genes related to atrial fibrillation. Among the polymorphisms of the angiotensin-converting enzyme gene, the 2350 G/A polymorphism (rs4343) is known to have the most significant effects on the plasma angiotensin-converting enzyme concentration. The aim of the present study was to investigate the association of the angiotensin-converting enzyme 2350 G/A polymorphism with atrial fibrillation in Han Chinese patients with essential hypertension. METHODS: A total of 169 hypertensive patients were eligible for this study. Patients with atrial fibrillation (nâ=â75) were allocated to the atrial fibrillation group, and 94 subjects without atrial fibrillation were allocated to the control group. The PCR-based restriction fragment length polymorphism technique was used to assess the genotype frequencies. RESULTS: The distributions of the angiotensin-converting enzyme 2350 G/A genotypes (GG, GA, and AA, respectively) were 40.43%, 41.49%, and 18.08% in the controls and 18.67%, 46.67%, and 34.66% in the atrial fibrillation subjects (pâ=â0.037). The frequency of the A allele in the atrial fibrillation group was significantly greater than in the control group (58.00% vs. 38.83%, pâ=â0.0007). Compared with the wild-type GG genotype, the GA and AA genotypes had an increased risk for atrial fibrillation. Additionally, atrial fibrillation patients with the AA genotype had greater left atrial dimensions than the patients with the GG or GA genotypes (
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