ABSTRACT
We investigate the absorption and emission features in observations of GX 301-2 detected with Insight-HXMT/LE in 2017–2019. At different orbital phases, we found prominent Fe Kα, Kβ, and Ni ...Kα lines, as well as Compton shoulders and Fe K-shell absorption edges. These features are due to the X-ray reprocessing caused by the interaction between the radiation from the source and surrounding accretion material. According to the ratio of iron lines (Kα and Kβ), we infer the accretion material is in a low ionization state. We find an orbital-dependent local absorption column density, which has a large value and strong variability around the periastron. We explain its variability as a result of inhomogeneities of the accretion environment and/or instabilities of accretion processes. In addition, the variable local column density is correlated with the equivalent width of the iron Kα lines throughout the orbit, which suggests that the accretion material near the neutron star is spherically distributed.
We examined the variation in plasma levels of endothelin (ET), calcitonin gene-related peptide (CGRP), nitric oxide (NO), and malondialdehyde (MDA), as well as superoxide dismutase (SOD) activity, in ...acute myocardial ischemia reperfusion injury in a rabbit model. Seventy rabbits were randomly assigned into 3 groups. Open-chest surgery (OCS) was performed for all rabbits. Group A (N = 20) received sham-surgery, group B (N = 25) was the reperfusion group, and group C (N = 25) was the infarction group. At 12 h after chest clo-sure, plasma ET levels in groups B and C were clearly increased, while CGRP levels were clearly decreased, particularly in group B. At 24 h after chest closure, ET levels were higher than before OCS, while there was no significant difference between groups B and C. ET in group B was decreased, while that in group C was increased at 12 h. No significant difference in CGRP was observed between 12 and 24 h after chest closure. NO levels in groups B and C at 12 h after chest closure were significantly decreased compared to those before OCS. NO levels in group B at 24, 48, and 72 h were significantly lower than those at 12 h, while those of group C were not significantly changed after 12 h. Dynamic monitoring and comparison of plasma levels of ET, CGRP, NO, and MDA as well as SOD activity revealed that appropriate intervention of these factors may reduce reperfusion injury.
In this paper, the K-shell ionization cross sections of Al by 4–9 keV positron impact have been measured for the first time. Firstly, the K-shell characteristic X-ray yields produced by positron ...collision with thick Al target were measured. In this process, online monitoring technology was developed to obtain the accurate number of incident positrons that collided with the thick Al target, and spectrum smoothing technology was introduced to obtain the accurate Kαβ characteristic peak net counts generated by positron collision with the thick Al target. Next, combined with Monte Carlo (MC) simulation and theoretical calculation, the contributions of the multiple scattering of incident positrons, from the bremsstrahlung and annihilation photons and other secondary particles to the experimental characteristic X-ray yields were corrected. Finally, the corrected experimental characteristic X-ray yields were converted into K-shell ionization cross sections by the numerical calculation method. The theoretical values of the distorted wave Born approximation (DWBA) were compared with the experimental results of the Al K-shell ionization cross sections by 4-9 keV positron impact. The result shows that the predicted values of DWBA theory slightly overestimate the experimental results, but the trend is basically consistent with them.
•The Kαβ ionization cross sections of Al by keV positron impact have been measured.•Use numerical calculation method to convert into ionization cross sections.•Compared with theoretical values of the distorted wave Bonn approximation (DWBA).•Spectrum smoothing technology was used to obtain the Kαβ peak net counts.
To investigate the association between oxygen saturation (SpO
) and risk of 3-year all-cause mortality among Chinese older adults aged 65 or over.
The participants were enrolled from Healthy Aging ...and Biomarkers Cohort Study in year of 2012 to 2014 in 9 longevity areas in China. In this prospective cohort study, 2 287 participants aged 65 or over were enrolled. Data on SpO
and body measurements were collected at baseline in 2012, and data on survival outcome and time of mortality were collected at the follow-up in 2014. Participants were divided into two groups according to whether SpO
was abnormal (SpO
<94% was defined as abnormal).
The 2 287 participants were (86.5±12.2) years old, 1 006 were males (44.0%), and 315 (13.8%) were abnormal in SpO
. During follow-up in 2014, 452 were died, 1 434 were survived, and 401 were lost to follow-up. The all-cause mortality rate was 19.8%, and the follow-up rate was 82.5%. The mortality rate of SpO
in normal group was 21.1%, and that of abnormal group was 41.6% (
0.001)
The utility of mechanical metamaterials for biomedical applications has seldom been explored. Here we show that a metamaterial that is mechanically responsive to antibody-mediated biorecognition can ...serve as an optical interferometric mask to molecularly profile extracellular vesicles in ascites fluid from patients with cancer. The metamaterial consists of a hydrogel responsive to temperature and redox activity functionalized with antibodies to surface biomarkers on extracellular vesicles, and is patterned into micrometric squares on a gold-coated glass substrate. Through plasmonic heating, the metamaterial is maintained in a transition state between a relaxed form and a buckled state. Binding of extracellular vesicles from the patient samples to the antibodies on the hydrogel causes it to undergo crosslinking, induced by free radicals generated via the activity of horseradish peroxidase conjugated to the antibodies. Hydrogel crosslinking causes the metamaterial to undergo fast chiral re-organization, inducing amplified changes in its mechanical deformation and diffraction patterns, which are detectable by a smartphone camera. The mechanical metamaterial may find broad utility in the sensitive optical immunodetection of biomolecules.
We aimed to investigate the predictive value of a systematic serum inflammation index, pan-immune-inflammatory value (PIV), in pathological complete response (pCR) of patients treated with ...neoadjuvant immunotherapy to further promote ideal patients' selection.
The clinicopathological and baseline laboratory information of 128 NSCLC patients receiving neoadjuvant immunochemotherapy between October 2019 and April 2022 were retrospectively reviewed. We performed least absolute shrinkage and selection operator (LASSO) algorithm to screen candidate serum biomarkers for predicting pCR, which further entered the multivariate logistic regression model to determine final biomarkers. Accordingly, a diagnostic model for predicting individual pCR was established. Kaplan-Meier method was utilized to estimate curves of disease-free survival (DFS), and the Log rank test was analyzed to compare DFS differences between patients with and without pCR.
Patients with NSCLC heterogeneously responded to neoadjuvant immunotherapy, and those with pCR had a significant longer DFS than patients without pCR. Through LASSO and the multivariate logistic regression model, PIV was identified as a predictor for predicting pCR of patients. Subsequently, a diagnostic model integrating with PIV, differentiated degree and histological type was constructed to predict pCR, which presented a satisfactory predictive power (AUC, 0.736), significant agreement between actual and our nomogram-predicted pathological response.
Baseline PIV was an independent predictor of pCR for NSCLC patients receiving neoadjuvant immunochemotherapy. A significantly longer DFS was achieved in patients with pCR rather than those without pCR; thus, the PIV-based diagnostic model might serve as a practical tool to identify ideal patients for neoadjuvant immunotherapeutic guidance.
Context. The lithium abundances in a few percent of giants exceed the value predicted by the standard stellar evolution models, and the mechanisms of Li enhancement are still under debate. The Large ...Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) survey has obtained over six million spectra in the past five years, and thus provides a great opportunity to search these rare objects and to more clearly understand the mechanisms of Li enhancement. Aims. The aim of this work is to accurately measure the Li abundance and investigate the possible mechanisms of Li enrichment for a newly found super Li-rich giant, TYC 3251-581-1, located near the luminosity function bump with a low carbon isotopic ratio. Methods. Based on the high-resolution spectrum we obtained the stellar parameters (Teff, logg, Fe/H), and determined the elemental abundances of Li, C, N, α, Fe-peak, r-process, s-process elements, and the projected rotational velocity. For a better understanding of the effect of mixing processes, we also derived the 12C to 13C ratio, and constrained the evolutionary status of TYC 3251-581-1 based on the BaSTI stellar isochrones. Results. The super Li-rich giant TYC 3251-581-1 has A(Li) = 3.51, the average abundance of two lithium lines at λ = 6708 Å and 6104 Å based on the non-local thermodynamic equilibrium analysis. The atmospheric parameters show that our target locates on the luminosity function bump. The low carbon isotopic ratio (12C∕13C = 9.0), a slow rotational velocity vsini = 2.2 km s−1, and no sign of IR excess suggest that additional mixing after first dredge up (FDU) should occur to bring internal synthesized Li to the surface. The low carbon (C∕Fe ~−0.34) and enhanced nitrogen (N∕Fe ~ 0.33) are also consistent with the sign of mixing. Conclusions. Given the evolutionary stage of TYC 3251-581-1 with the relatively low 12C∕13C, the internal production which replenishes Li in the outer layer is the most likely origin of Li enhancement for this star.
Somatic genome rearrangements are thought to play important roles in cancer development. We optimized a long-span paired-end-tag (PET) sequencing approach using 10-Kb genomic DNA inserts to study ...human genome structural variations (SVs). The use of a 10-Kb insert size allows the identification of breakpoints within repetitive or homology-containing regions of a few kilobases in size and results in a higher physical coverage compared with small insert libraries with the same sequencing effort. We have applied this approach to comprehensively characterize the SVs of 15 cancer and two noncancer genomes and used a filtering approach to strongly enrich for somatic SVs in the cancer genomes. Our analyses revealed that most inversions, deletions, and insertions are germ-line SVs, whereas tandem duplications, unpaired inversions, interchromosomal translocations, and complex rearrangements are over-represented among somatic rearrangements in cancer genomes. We demonstrate that the quantitative and connective nature of DNA-PET data is precise in delineating the genealogy of complex rearrangement events, we observe signatures that are compatible with breakage-fusion-bridge cycles, and we discover that large duplications are among the initial rearrangements that trigger genome instability for extensive amplification in epithelial cancers.
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