1,748 research outputs found
The width-flux relation of the broad iron line during the state transition of the black hole X-ray binaries
The observation of varying broad iron lines during the state transition of
the black hole X-ray binaries (BHXBs) have been accumulating.In this work, the
relation between the normalized intensity and the width of iron lines is
investigated, in order to understand better the variation of iron lines and
possibly its connection to state transition. Considering the uncertainties due
to ionization and illuminating X-rays, only the effects of geometry and gravity
are taken into account. Three scenarios were studied, i.e., the continuous disk
model, innermost annulus model, and the cloud model. As shown by our
calculations, at given iron width, the line flux of the cloud model is smaller
than that of the continuous disk model; while for the innermost annulus model,
the width is almost unrelated with the flux. The range of the line strength
depends on both the BH spin and the inclination of the disk. We then apply to
the observation of MAXI J1631-479 by NuSTAR during its decay from the soft
state to the intermediate state. We estimated the relative line strength and
width according to the spectral fitting results by Xu et al.(2020), and then
compared with our theoretical width-flux relation. It was found that the cloud
model was more favored. We further modeled the iron line profiles, and found
that the cloud model can explain both the line profile and its variation with
reasonable parameters.Comment: 7 figures, 12 pages, accepted for publication in RA
Localization of gauge field by non-minimal coupling with gravity
In this paper, we investigate the localization of the gauge field on
Randall-Sundrum-like braneworld models. The localization of the gauge
field is important because it plays a fundamental role in the branworld
theories. To achieve the localization, we propose a novel action with a
non-minimal coupling between the gauge field and gravity. We find that
the mass spectrum of the gauge field is continuous, without any gap between the
zero-mass mode and the massive modes, and except for the zero-mass mode all the
massive modes are not localized on the brane. Furthermore, the massive modes
have negative squared masses, indicating they are tachyonic. Our analysis can
be applied to a wide range of thin and thick braneworld scenarios, provided
that the five-dimensional spacetime is asymptotically anti-de Sitter.Comment: 10 pages, 2 figures, Accepted by JCA
NADPH Oxidase 1 and Its Derived Reactive Oxygen Species Mediated Tissue Injury and Repair
Reactive oxygen species are mostly viewed to cause oxidative damage to various cells and induce organ dysfunction after ischemia-reperfusion injury. However, they are also considered as crucial molecules for cellular signal transduction in biology. NADPH oxidase, whose only function is reactive oxygen species production, has been extensively investigated in many cell types especially phagocytes. The deficiency of NADPH oxidase extends the process of inflammation and delays tissue repair, which causes chronic granulomatous disease in patients. NADPH oxidase 1, one member of the NADPH oxidase family, is not only constitutively expressed in a variety of tissues, but also induced to increase expression in both mRNA and protein levels under many circumstances. NADPH oxidase 1 and its derived reactive oxygen species are suggested to be able to regulate inflammation reaction, cell proliferation and migration, and extracellular matrix synthesis, which contribute to the processes of tissue injury and repair
Solar microwave millisecond spike at 2.84 GHz
Using the high time resolution of 1 ms, the data of solar microwave millisecond spike (MMS) event was recorded more than two hundred times at the frequency of 2.84 GHz at Beijing (Peking) Observatory since May 1981. A preliminary analysis was made. It can be seen from the data that the MMS-events have a variety of the fast activities such as the dispersed and isolated spikes, the clusters of the crowded spikes, the weak spikes superimposed on the noise background, and the phenomena of absorption. The marked differences from that observed with lower time resolution are presented. Using the data, a valuable statistical analysis was made. There are close correlations between MMS-events and hard X-ray bursts, and fast drifting bursts. The MMS events are highly dependent on the type of active regions and the magnetic field configuration. It seems to be crucial to find out the accurate positions on the active region where the MMS-events happen and to make co-operative observations at different bands during the special period when specific active regions appear on the solar disk
Different Spontaneous Pulmonary Metastasis Inhibitions against Lewis Lung Carcinoma in Mice by Bisdioxopiperazine Compounds of Different Treatment Schedules
Spontaneous neoplasm metastasis, a fatalist pathological feature of cancer, is a long-evolving, multi-steps process that can now only be treated or controlled by drugs or immuno-modulators. As we have previously hypothesized, each drug or immuno-modulator might act differently within various stages of a metastasis. Therefore any researches helping to determine these differences will be beneficial for updating therapeutics for metastasis. In this work, we have testified this hypothesis by using a series of well-known anti-metastatic agents – Bisdioxopiperazine compounds
Recommended from our members
Strong habitat-specific phenotypic plasticity but no genome-wide differentiation across a rainforest gradient in an African butterfly
Habitat-specific thermal responses are well documented in various organisms and likely determine the vulnerability of populations to climate change. However, the underlying roles of genetics and plasticity that shape such habitat-specific patterns are rarely investigated together. Here we examined the thermal plasticity of the butterfly Bicyclus dorothea originating from rainforest and ecotone habitats in Cameroon under common garden conditions. We also sampled wild-caught butterflies from forest and ecotone sites and used RADseq to explore genome-wide population differentiation. We found differences in the level of phenotypic plasticity across habitats. Specifically, ecotone populations exhibited greater sensitivity in wing eyespot features with variable development temperatures relative to rainforest populations. Known adaptive roles of wing eyespots in Bicyclus species suggest that this morphological plasticity is likely under divergent selection across environmental gradients. However, we found no distinct population structure of genome-wide variation between habitats, suggesting high level of ongoing gene flow between habitats is homogenizing most parts of the genome
Loop-Mediated Isothermal Amplification Assay Targeting the MOMP Gene for Rapid Detection of Chlamydia psittaci Abortus Strain
For rapid detection of the Chlamydia psittaci abortus strain, a loop-mediated isothermal amplification (LAMP) assay was developed and evaluated in this study. The primers for the LAMP assay were designed on the basis of the main outer membrane protein (MOMP) gene sequence of C. psittaci. Analysis showed that the assay could detect the abortus strain of C. psittaci with adequate specificity. The sensitivity of the test was the same as that of the nested-conventional PCR and higher than that of chick embryo isolation. Testing of 153 samples indicated that the LAMP assay could detect the genome of the C. psittaci abortus strain effectively in clinical samples. This assay is a useful tool for rapid diagnosis of C. psittaci infection in sheep, swine and cattle
Alcohol Consumption and Ankle-to-Brachial Index: Results from the Cardiovascular Risk Survey
BACKGROUND AND METHODOLOGY: A low ankle-to-brachial index (ABI) is a strong correlate of cardiovascular disease and subsequent mortality. The relationship between ABI and alcohol consumption remains unclear. Data are from the Cardiovascular Risk Survey (CRS), a multiple-ethnic, community-based, cross-sectional study of 14,618 Chinese people (5757 Hans, 4767 Uygurs, and 4094 Kazakhs) aged 35 years and over at baseline from Oct. 2007 to March 2010. The relationship between alcohol intake and ABI was determined by use of analysis of covariance and multivariable regressions. PRINCIPAL FINDINGS: In men, alcohol consumption was significantly associated with ABI (P<0.001). After adjusted for the confounding factors, such as age, sex, ethnicity, body mass index, smoking, work stress, diabetes, and fasting blood glucose, the difference remained significant (P<0.001); either the unadjusted or multivariate-adjusted odds ratio (OR) for peripheral artery disease (PAD) was significantly higher in men who consumed >60.0 g/d [OR = 3.857, (95% CI: 2.555-5.824); OR = 2.797, (95% CI: 1.106-3.129); OR = 2.878, (95% CI: 1.215-4.018); respectively] and was significantly lower in men who consumed 20.1-40.0 g/d [OR= 0.330, (95% CI: 0.181-0.599); OR = 0.484, (95% CI: 0.065-0.894); OR = 0.478, (95% CI: 0.243-1.534); respectively] and 40.1-60.0 g/d [OR= 0.306, (95% CI: 0.096-0.969); OR = 0.267, (95% CI: 0.087-0.886); OR = 0.203, (95% CI: 0.113-0.754); respectively] compared with never drinking, respectively (all P<0.01). Neither in unadjusted nor in multivariate-adjusted model was the association between ABI and alcohol consumption significant (all P>0.05) in women. Similarly, PAD was not correlated with alcohol intake in women (all P>0.05). CONCLUSIONS/SIGNIFICANCE: Our results indicated that in Chinese men, alcohol consumption was associated with peripheral artery disease, and consumption of less than 60 g/d had an inverse association with peripheral atherosclerosis whereas consumption of 60 g/d or more had a positive association
Alendronate versus Raloxifene for Postmenopausal Women: A Meta-Analysis of Seven Head-to-Head Randomized Controlled Trials
Purpose. The aim of this study was to directly compare the efficacy and the safety of the two agents for postmenopausal women. Methods/Principal Findings. Electronic databases were searched for relevant articles that met our predefined inclusion criteria. Seven randomized controlled trials (RCTs) involving 4054 women were identified and included. Although Aln was more effective than Rlx in increasing bone mineral density (BMD), no statistical differences were observed in reducing the risk of neither vertebral fractures (P=0.45) nor nonvertebral fractures (P=0.87) up to two-year followup. Aln reduced the risk of vasomotor (P=0.006) but increased the risk of diarrhea compared to Rlx (P=0.01). Our subgroup analysis further indicated the difference between Aln and Rlx in fracture risk and was not materially altered by the administration pattern, the age. The weekly strategy of Aln would further reduce the upper gastrointestinal (GI) disorders and might gain more bone mass increment at lumbar spine compared to its daily treatment. Conclusion. There was no evidence of difference of fracture risk reduction between Aln and Rlx. In addition, age did not obviously influence their relative antifracture efficacy. For Aln the weekly strategy would further reduce the upper GI disorders and gain more bone mass increment compared to the daily treatment. During clinical decision making, the patients’ adherence and the related side-effects associated with both drugs should also be taken into account
- …