γ-ray flash generation in near-critical-density target irradiated by four symmetrical colliding laser pulses is numerically investigated. With peak intensities about 10^{23} W/cm^{2}, the laser ...pulses boost electron energy through direct laser acceleration, while pushing them inward with the ponderomotive force. After backscattering with counterpropagating laser, the accelerated electron is trapped in the electromagnetic standing waves or the ponderomotive potential well created by the coherent overlapping of the laser pulses, and emits γ-ray photons in a multiple-laser-scattering regime, where electrons act as a medium transferring energy from the laser to γ rays in the ponderomotive potential valley.
Propolis has a broad spectrum of biological activities; however, whether its essential oils have neuroprotective effects is unknown. In this study, we found that propolis essential oil (PEO) could ...significantly reverse the anxiety-like behavior of restraint-stressed mice, and has no effect on locomotor activity. Furthermore, PEO significantly decreased the plasma levels of cortisol (CORT), adrenocorticotropic hormone (ACTH) and malondialdehyde (MDA), whereas it increased the activity of superoxide dismutase (SOD) in restraint-stressed mice. These results strongly suggest that PEO has therapeutic effects on anxiety through antagonizing the hyperfunction of hypothalamic–pituitary–adrenal (HPA) axis and improving the ability of antioxidation in brain tissue.
The repeatability of laser proton accelerator is mainly limited by laser plasma interaction, laser target coupling and laser parameter variation. In our recent experiments performed on the Compact ...Laser Plasma Accelerator at Peking University, gain of proton beams with improved repeatability is demonstrated. In order to control the laser plasma interaction in pre-plasma, cross polarized-wave generation technique is employed to provide a laser pulse with an ultrahigh contrast of 10−10 A semi-automatic laser and target alignment system with a sensitivity of few microns is employed. The repetition rate of the laser pro-ton accelerator is at the level of 0.1 Hz which is beneficial to decrease laser parameter variation. The shot-to-shot variation of proton energies is about 9% for a level of confidence of 0.95.
The acceleration of ultrathin targets driven by intense laser pulses induces Rayleigh–Taylor-like instability. Apart from laser and target configurations, we find that electron heating and surface ...rippling, effects inherent to the interaction process, have an important role in instability evolution and growth. By employing a simple analytical model and two-dimensional particle-in-cell simulations, we show that the onset of electron heating in the early stage of the acceleration suppresses the growth of small-scale modes, but it has little influence on the growth of large-scale modes, which thus become dominant. With the growth of surface ripples, a mechanism that can significantly influence the growth of these large-scale modes is found. The laser field modulation caused by surface rippling generates an oscillatory ponderomotive force, directly modulating transverse electron density at a faster growth rate than that of ions and eventually enhancing instability growth. Our results show that when surface deformation becomes obvious, electron surface oscillation at 2ω0 (where ω0 is the laser frequency) is excited simultaneously, which can be seen as a signature of this mechanism.
Wetland species mat rush (Juncus effusus L.) is an important economic plant, but no information is available regarding plant regeneration, callus induction, and its proliferation from in vitro seed ...grown plantlets. The present study investigates the effects of growth regulator combinations and medium innovation on tissue culture system of five mat rush varieties. Addition of N6-benzyladenine (BA) and 2,4-dichlorophenoxyacetic acid (2,4-D) in Murashige and Skoog (MS) medium showed significantly positive effect on callus proliferation, plant regeneration, and its multiplication compared to the medium devoid of BA. The highest callus induction frequency (80.95%, 90.48%, 75.40%, 70.83%, and 83.33%) was observed in MS medium containing 0.5 mg L⁻¹ (2.2 μM) BA in Yinlin-1, Nonglin-4, Gangshan, Taicao, and Taiwan green, respectively. Various growth regulator combinations with successive subculture (medium replacement) were found essential to develop organogenic calluses and to regenerate shoots. The combination of 0.1 mg L⁻¹ BA (0.4 μM) and 2 mg L⁻¹ 2,4-D (9.0 μM) in MS medium was found best for callus proliferation for all the varieties under trial. The plant regeneration required two steps involving successive medium replacements as well as optimal hormonal balances. Successful plant regeneration (over 70%) was observed only by transferring the organogenic callus from regeneration medium I MS medium containing 0.5 mg L⁻¹ BA (2. μM) and 1.0 mg L⁻¹ kinetin (KT; 4.6 μM) to the regeneration medium II MS medium containing 0.5 mg L⁻¹ BA (2.2 μM), 1.0 mg L⁻¹ KT (4.6 μM) and 3.0 mg L⁻¹ indoleacetic acid (IAA; 17.1 μM). Our results confirmed the importance of the ratio of auxin (IAA) to cytokinin (BA and KT) in the manipulation of shoot regeneration in J. effusus L. The maximum plant survival frequency and multiplication rates (90.97% and 5.40 and 94.23% and 8.25) were recorded in the presence of 0.5 mg L⁻¹ BA (2.2 μM) in the 1/2 MS multiplication medium for the varieties of Nonglin-4 and Taicao, respectively. About 100% survival rate was also observed for all the varieties in soil conditions. The efficient plant regeneration system developed here will be helpful for rapid micropropagation and further genetic improvement in J. effusus L.
•A governance framework is established for local sourcing of overseas BRI projects.•A fuzzy DEMATEL approach is applied to evaluate the framework.•Relational governance factors play a prominent role ...in local sourcing practices.•Formal governance factors are the precondition for relational factors.
A unified framework is proposed to investigate the ex-post factors of local sourcing practices in overseas projects for the Belt and Road Initiative, which includes twelve governance factors in four dimensions, i.e., coordinated adaptation, control and safeguarding, incentives and payment structure, and policies and regulations. A fuzzy Decision Making Trial and Evaluation Laboratory (DEMATEL) approach is applied to evaluate the inter-relationships among the factors. The results indicate that relational governance mechanisms such as trust building play a prominent role in implementing local sourcing practices while formal governance mechanisms such as country-level policies and regulations are the precondition for relational mechanisms.
In this study, the density distributions of large nuclei are typically modeled with a Woods–Saxon distribution characterized by a radius R0 and skin depth a. Deformation parameters β are then ...introduced to describe non-spherical nuclei using an expansion in spherical harmonics R0(1+β2Y20+β4Y40). But when a nucleus is non-spherical, the R0 and a inferred from electron scattering experiments that integrate over all nuclear orientations cannot be used directly as the parameters in the Woods–Saxon distribution. In addition, the β2 values typically derived from the reduced electric quadrupole transition probability B(E2)↑ are not directly related to the β2 values used in the spherical harmonic expansion. B(E2)↑ is more accurately related to the intrinsic quadrupole moment Q0 than to β2. One can however calculate Q0 for a given β2 and then derive B(E2)↑ from Q0. In this paper we calculate and tabulate the R0, a , and β2 values that when used in a Woods–Saxon distribution, will give results consistent with electron scattering data. We then present calculations of the second and third harmonic participant eccentricity (ε2 and ε3) with the new and old parameters. We demonstrate that ε3 is particularly sensitive to a and argue that using the incorrect value of a has important implications for the extraction of viscosity to entropy ratio (η/s) from the QGP created in Heavy Ion collisions.
ABSTRACT
Ethylene has been regarded as a stress hormone involved in many stress responses. However, ethylene receptors have not been studied for the roles they played under salt stress condition. ...Previously, we characterized an ethylene receptor gene NTHK1 from tobacco, and found that NTHK1 is salt‐inducible. Here, we report a further investigation towards the function of NTHK1 in response to salt stress by using a transgenic approach. We found that NTHK1 promotes leaf growth in the transgenic tobacco seedlings but affects salt sensitivity in these transgenic seedlings under salt stress condition. Differential Na+/K+ ratio was observed in the control Xanthi and NTHK1‐transgenic plants after salt stress treatment. We further found that the NTHK1 transgene is also salt‐inducible in the transgenic plants, and the higher NTHK1 expression results in early inductions of the ACC (1‐aminocyclopropane‐1‐carboxylic acid) oxidase gene NtACO3 and ethylene responsive factor (ERF) genes NtERF1 and NtERF4 under salt stress. However, NTHK1 suppresses the salt‐inducible expression of the ACC synthase gene NtACS1. These results indicate that NTHK1 regulates salt stress responses by affecting ion accumulation and related gene expressions, and hence have significance in elucidation of ethylene receptor functions during stress signal transduction.
To describe the characteristics of plasma lipid proliferation in cervical cancer and further evaluate the prognostic significance of lipid levels in cervical cancer.
We retrospectively reviewed 1713 ...patients with cervical cancer in our hospital. The preoperative plasma lipid profile, including cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL), and low-density lipoprotein cholesterol (LDL), of 1713 cervical cancer patients was compared with that of 10,397 healthy women. Then, we evaluated the impact of lipids on overall survival (OS) and recurrence-free survival (RFS) in cervical cancer using univariate and multivariate Cox models.
While plasma TC, TG, and LDL were significantly higher, HDL was lower in patients with cervical cancer than in healthy women. TG was identified as an independent predictor for RFS and OS among patients with cervical cancer. Further stratified by age, patients with higher TGs showed a significantly worse RFS and OS than those with lower TGs among patients ≥50 years old but not among those <50 years old.
Cervical cancer was associated with a disordered lipid profile. Hypertriglyceridemia was an independent poor prognostic indicator for cervical cancer, especially for elderly patients. Strengthening lipid management may be beneficial for improving postoperative OS and RFS in patients with cervical cancer.
We report a proposal to observe the two-photon Breit-Wheeler process in plasma driven by compact lasers. A high charge electron bunch can be generated from laser plasma wakefield acceleration when a ...tightly focused laser pulse transports in a sub-critical density plasma. The electron bunch scatters with the laser pulse coming from the opposite direction and results the emitting of high brilliance X-ray pulses. In a three-dimensional particle-in-cell simulation with a laser pulse of \(\sim\)10 J, one could produce a X-ray pulse with photon number higher than \(3\times10^{11}\) and brilliance above \(1.6\times 10^{23}\) photons/s/mm\(^2\)/mrad\(^2\)/0.1\(\%\)BW at 1 MeV. The X-ray pulses collide in the plasma and create more than \(1.1\times 10^5\) electron-positron pairs per shot. It is also found that the positrons can be accelerated transversely by a transverse electric field generated in the plasma, which enables the safe detection in the direction away from the laser pulses. This proposal which has solved key challenges in laser driven photon-photon collision could demonstrate the two-photon Breit-Wheeler process on a much more compact device in a single shot.
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