ABSTRACT
The merging of double white dwarfs (WDs) may produce the events of accretion-induced collapse (AIC) and form single neutron stars (NSs). Meanwhile, it is also notable that the recently ...proposed WD+He subgiant scenario has a significant contribution to the production of massive double WDs, in which the primary WD grows in mass by accreting He-rich material from a He subgiant companion. In this work, we aim to study the binary population synthesis (BPS) properties of AIC events from the double WD mergers by considering the classical scenarios and also the contribution of the WD+He subgiant scenario to the formation of double WDs. First, we provided a dense and large model grid of WD+He star systems for producing AIC events through the double WD merger scenario. Secondly, we performed several sets of BPS calculations to obtain the rates and single NS number in our Galaxy. We found that the rates of AIC events from the double WD mergers in the Galaxy are in the range of $1.4{-}8.9\times 10^{\rm -3}\, \rm yr^{\rm -1}$ for all ONe/CO WD+ONe/CO WD mergers, and in the range of $0.3{-}3.8\times 10^{\rm -3}\, \rm yr^{\rm -1}$ when double CO WD mergers are not considered. We also found that the number of single NSs from AIC events in our Galaxy may range from 0.328 × 107 to 1.072 × 108. The chirp mass of double WDs for producing AIC events distribute in the range of $0.55{-}1.25\, \rm M_{\odot }$. We estimated that more than half of double WDs for producing AIC events are capable to be observed by the future space-based gravitational wave detectors.
A new kind of biomedical shape memory TiNiAg alloy with antibacterial function was successfully developed in the present study by the introduction of pure Ag precipitates into the TiNi matrix phase. ...The microstructure, mechanical property, corrosion resistance, ion release behavior in simulated body fluid, cytotoxicity and antibacterial properties were systematically investigated. The typical microstructural feature of TiNiAg alloy at room temperature was tiny pure Ag particles (at submicrometer or micrometer scales with irregular shape) randomly distributed in the TiNi matrix phase. The presence of Ag precipitates was found to result in a slightly higher tensile strength and larger elongation of TiNiAg alloy in comparison with that of TiNi binary alloy. Furthermore, a maximum shape recovery strain of ∼6.4% was obtained with a total prestrain of 7% in the TiNiAg alloy. In electrochemical and immersion tests, TiNiAg alloy presented good corrosion resistance in simulated body fluid, comparable with that of CP Ti and TiNi alloy. The cytotoxicity evaluation revealed that TiNiAg alloy extract induced slight toxicity to cells, but the viability of experimental cells was similar to or higher than that of TiNi alloy extract. In vitro bacterial adhesion study indicated a significantly reduced number of bacteria (
S. aureus,
S. epidermidis and
P. gingivalis) on the TiNiAg alloy plate surface when compared with that on TiNi alloy plate surface, and the corresponding antibacterial mechanism for the TiNiAg alloy is discussed.
This prospective, randomized, phase III trial shows that prophylactic cranial irradiation prolongs disease-free survival, decreases the rate of cerebral metastases and does not affect quality-of-life ...for patients with fully resected postoperative pathologically confirmed stage IIIA-N2 non-small-cell lung cancer and high risk of cerebral metastases after adjuvant chemotherapy.
This study compared prophylactic cranial irradiation (PCI) with observation in patients with resected stage IIIA–N2 non-small-cell lung cancer (NSCLC) and high risk of cerebral metastases after adjuvant chemotherapy.
In this open-label, randomized, phase III trial, patients with fully resected postoperative pathologically confirmed stage IIIA–N2 NSCLC and high cerebral metastases risk without recurrence after postoperative adjuvant chemotherapy were randomly assigned to receive PCI (30 Gy in 10 fractions) or observation. The primary end point was disease-free survival (DFS). The secondary end points included the incidence of brain metastases, overall survival (OS), toxicity and quality of life.
This trial was terminated early after the random assignment of 156 patients (81 to PCI group and 75 to control group). The PCI group had significantly lengthened DFS compared with the control group, with a median DFS of 28.5 months versus 21.2 months hazard ratio (HR), 0.67; 95% confidence interval (CI) 0.46–0.98;P = 0.037. PCI was associated with a decrease in risk of brain metastases (the actuarial 5-year brain metastases rate, 20.3% versus 49.9%; HR, 0.28; 95% CI 0.14–0.57;P < 0.001). The median OS was 31.2 months in the PCI group and 27.4 months in the control group (HR, 0.81; 95% CI 0.56–1.16;P = 0.310). While main toxicities were headache, nausea/vomiting and fatigue in the PCI group, they were generally mild.
In patients with fully resected postoperative pathologically confirmed stage IIIA–N2 NSCLC and high risk of cerebral metastases after adjuvant chemotherapy, PCI prolongs DFS and decreases the incidence of brain metastases.
Abstract We report the timing analysis of PSR J1846−0513, a pulsar discovered by the Five-hundred-meter Aperture Spherical radio Telescope (FAST) in Commensal Radio Astronomy FAST Survey. The pulsar ...possesses a spin period of 23.36 ms and a spin-down rate ( P ̇ ) of 1.0106(3) × 10 −18 s s −1 , and it is located in an eccentric orbit ( e ∼0.208) with an orbital period of 0.61 days. The characteristic age and surface magnetic field of the pulsar are found to be 366.62 Myr and 4.9178 × 10 9 G, respectively, indicating that it is a recycled pulsar. Using over two years of timing data, we measure the periastron advance ω ̇ = 0.8956(8) deg yr −1 . By assuming that this effect is purely relativistic, we have estimated the total mass M = 2.6287(35) M ⊙ and obtained an upper limit for the pulsar mass and a lower limit for the companion’s mass. Our results indicate that this is a double neutron star system.
Transiting extrasolar planets constitute only a small fraction of the range of stellar systems found to display periodic, shallow dimmings in wide-field surveys employing small-aperture camera ...arrays. Here we present an efficient selection strategy for follow-up observations, derived from analysis of the light curves of a sample of 67 SuperWASP targets that passed the selection tests we used in earlier papers, but which have subsequently been identified either as planet hosts or as astrophysical false positives. We determine the system parameters using Markov-chain Monte Carlo analysis of the SuperWASP light curves. We use a constrained optimization of χ2 combined with a Bayesian prior based on the main-sequence mass and radius expected from the Two Micron All Sky Survey J−H colour. The Bayesian nature of the analysis allows us to quantify both the departure of the host star from the main-sequence mass–radius relation and the probability that the companion radius is less than 1.5 Jupiter radii. When augmented by direct light-curve analyses that detect binaries with unequal primary and secondary eclipses, and objects with aperture blends that are resolved by SuperWASP, we find that only 13 of the original 67 stars, including the three known planets in the sample, would qualify for follow-up. This suggests that planet discovery ‘hit rates’ better than one-in-five should be achievable. In addition, the stellar binaries that qualify are likely to have astrophysically interesting stellar or substellar secondaries.
We experimentally realize a universal set of single-bit and two-bit geometric quantum gates by adiabatically controlling solid-state spins in a diamond defect. Compared with the nonadiabatic ...approach, the adiabatic scheme for geometric quantum computation offers a unique advantage of inherent robustness to parameter variations, which is explicitly demonstrated in our experiment by showing that the single-bit gates remain unchanged when the driving field amplitude varies by a factor of 2 or the detuning fluctuates in a range comparable to the inverse of the gate time. The reported adiabatic control technique and its convenient implementation offer a paradigm for achieving quantum computation through robust geometric quantum gates, which is important for quantum information systems with parameter-fluctuation noise such as those from the inhomogeneous coupling or the spectral diffusion.
Multiphoton excitation laser scanning microscopy, relying on the simultaneous absorption of two or more photons by a molecule, is one of the most exciting recent developments in biomedical imaging. ...Thanks to its superior imaging capability of deeper tissue penetration and efficient light detection, this system becomes more and more an inspiring tool for intravital bulk tissue imaging. Two-photon excitation microscopy including 2-photon fluorescence and second harmonic generated signal microscopy is the most common multiphoton microscopic application. In the present review we take diverse ocular tissues as intravital samples to demonstrate the advantages of this approach. Experiments with registration of intracellular 2-photon fluorescence and extracellular collagen second harmonic generated signal microscopy in native ocular tissues are focused. Data show that the in-tandem combination of 2-photon fluorescence and second harmonic generated signal microscopy as two-modality microscopy allows for in situ co-localization imaging of various microstructural components in the whole-mount deep intravital tissues. New applications and recent developments of this high technology in clinical studies such as 2-photon-controlled drug release, in vivo drug screening and administration in skin and kidney, as well as its uses in tumourous tissues such as melanoma and glioma, in diseased lung, brain and heart are additionally reviewed. Intrinsic emission two-modal 2-photon microscopy/tomography, acting as an efficient and sensitive non-injurious imaging approach featured by high contrast and subcellular spatial resolution, has been proved to be a promising tool for intravital deep tissue imaging and clinical studies. Given the level of its performance, we believe that the non-linear optical imaging technique has tremendous potentials to find more applications in biomedical fundamental and clinical research in the near future.
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