Preparation and Characterization of Axial Gradient Silicon Carbide Fibers with Sinusoidal Electrical Resistivity

Two types of silicon carbide fibers with sinusoidal electrical resistivity were prepared by using different pyrolysis technology. The relationship between the microstructure and the electrical resistivity of these fibers was investigated and compared. The results indicated that carbon layer was the main conductive phase in the SiC fibers obtained by means of one step pyrolysis, whereas a free carbon phase governed the conductivity of the SiC fibers prepared through two step pyrolysis mode.

Concise and efficient direct-view generation of arbitrary cylindrical vector beams by a vortex half-wave plate

A concise, efficient, and practical direct-view scheme is presented to generate arbitrary cylindrical vector(CV)beams, including CV beams, vortex beams, and cylindrical vector vortex(CVV) beams, by a vortex half-wave plate(VHP). Six kinds of first-order and other high-order CV beams, such as azimuthally polarized(AP) beams, antivortex radial polarization mode beams, and three-order AP beams, are formed by simply rotating a half-wave plate. The Stokes parameters and double-slit interference of multitype CV beams are investigated in detail.The polarization parameters, including degree of polarization, polarization azimuth, and ellipticity, are obtained,which demonstrates the efficient generation of CV beams. In addition, the double-slit interference experiment is introduced in the setup, and fringe misplacement and tilt appear for CVV beams, in which the misplacement number M is 2P+1 for P ≤ 2 and 2P-1 for P ≥ 3, where P is the polarization order number, and the fringe tilt offset is positively related to the topological charge number l of CVV beams. In addition, new types of VHPs can be formed by cascading two or more VHPs when the types of available VHPs are limited, assisting in more flexible generation of multitype CV beams. It is experimentally demonstrated that arbitrary CV beams with high quality are effectively achieved by the proposed setup, and the double-slit interference method can be utilized to determine and analyze CV beams rapidly and concisely by practical performance, which shows the potential to be implemented as a commercial device.

Molybdenum and cadmium co-induce necroptosis through Th1/Th2 imbalance-mediated endoplasmic reticulum stress in duck ovaries

Cadmium(Cd)and excess molybdenum(Mo)pose serious threats to animal health.Our previous study has determined that Cd and/or Mo exposure can cause ovarian damage of ducks,while the specific mechanism is still obscure.To further investigate the toxic mechanism of Cd and Mo co-exposure in the ovary,forty 8-day-old female ducks were randomly allocated into four groups for 16 weeks,and the doses of Cd and Mo in basic diet per kg were as follows:control group,Mo group(100 mg Mo),Cd group(4 mg Cd),and Mo+Cd group(100 mg Mo+4 mg Cd).Cadmium sulfate 8/3-hydrate(CdSO_(4)·8/3H_(2)O)and hexaammonium molybdate((NH_(4))_(6)Mo_(7)O_(24)·4H_(2)O)were the origins of Cd and Mo,respectively.At the 16th week of the experiment,all ovary tissues were collected for the detection of related indexes.The data indicated that Mo and/or Cd induced trace element disorders and Th1/Th2 balance to divert toward Th1 in the ovary,which activated endoplasmic reticulum(ER)stress and then provoked necroptosis through triggering RIPK1/RIPK3/MLKL signaling pathway,and eventually caused ovarian pathological injuries and necroptosis characteristics.The alterations of above indicators were most apparent in the joint group.Above all,this research illustrates that Mo and/or Cd exposure can initiate necroptosis through Th1/Th2 imbalance-modulated ER stress in duck ovaries,and Mo and Cd combined exposure aggravates ovarian injuries.This research explores the molecular mechanism of necroptosis caused by Mo and/or Cd,which reveals that ER stress attenuation may be a therapeutic target to alleviate necroptosis.