Generation of High-Density High-Polarization Positrons via Single-Shot Strong Laser-Foil Interaction.

We put forward a novel method for producing ultrarelativistic high-density high-polarization positrons through a single-shot interaction of a strong laser with a tilted solid foil. In our method, the driving laser ionizes the target, and the emitted electrons are accelerated and subsequently generate abundant γ photons via the nonlinear Compton scattering, dominated by the laser. These γ photons then generate polarized positrons via the nonlinear Breit-Wheeler process, dominated by a strong self-generated quasistatic magnetic field B^{S}. We find that placing the foil at an appropriate angle can result in a directional orientation of B^{S}, thereby polarizing positrons. Manipulating the laser polarization direction can control the angle between the γ photon polarization and B^{S}, significantly enhancing the positron polarization degree. Our spin-resolved quantum electrodynamics particle-in-cell simulations demonstrate that employing a laser with a peak intensity of about 10^{23} W/cm^{2} can obtain dense (≳10^{18} cm^{-3}) polarized positrons with an average polarization degree of about 70% and a yield of above 0.1 nC per shot. Moreover, our method is feasible using currently available or upcoming laser facilities and robust with respect to the laser and target parameters. Such high-density high-polarization positrons hold great significance in laboratory astrophysics, high-energy physics, and new physics beyond the standard model.

Effects of chelated Zn/Cu/Mn on redox status, immune responses and hoof health in lactating Holstein cows.

To evaluate the effects of chelated Zn/Cu/Mn on redox status, immune responses and hoof health in lactating Holstein cows, 48 head in early lactation were divided into healthy or lame groups according to their gait score. Cows were fed the same amount of Zn/Cu/Mn as sulfate salts or in chelated forms for 180 days, and foot-and-mouth disease (FMD) vaccine was injected at day 90. The results showed that lame cows had lower antioxidant function, serum Zn/Mn levels, hair Cu levels, and hoof hardness. Moreover, increased antioxidant status, FMD antibody titers, serum and hair levels of Zn/Cu/Mn, and hoof hardness and decreased milk fat percent and arthritis biomarkers were observed in cows fed chelated Zn/Cu/Mn. In summary, supplementation with chelated Zn/Cu/Mn improved antioxidant status and immune responses, reduced arthritis biomarkers, and increased accumulation of Zn/Cu/Mn in the body and hoof hardness in dairy cows.

[Research progress of gammadelta T cell-based immunotherapy].

GammadeltaT cells are considered as linkage between innate and adaptive immune response, which recognize specific antigen without MHC-restriction. Vgamma9Vdelta2T cells, isolated from peripheral blood and tumor tissue, can be activated by non-peptide phosphoantigen through binding to its gammadeltaTCR and proliferate under IL-2 stimulation. It has been shown that Vgamma9Vdelta2T cells possess anticancer activity against several types of tumor in vitro, as well as inhibit the growth of lymphoma, breast cancer and malignant melanoma in vivo. The phase I clinical trial of the application of Vgamma9Vdelta2T cells in treatment of lung cancer, renal cancer and prostate cancer demonstrated promising results. This review summarizes the recent advances in antigen recognition and activation of gammadeltaT cells, and the gammadeltaT cell-based immunotherapy for cancer treatment.