Protease activated receptor 2 and epidermal growth factor receptor are involved in the regulation of human sperm motility

Aim： To investigate mechanisms of tryptase-induced reduction of sperm motility and explore whether epidermal growth factor receptor （EGF-R） and protease activated receptor 2 （PAR-2）- associated pathways are involved. Methods： Fresh semen was collected from healthy donors （n = 15）. Semen parameters and quality were assessed in accordance with the World Health Organization （WHO） criteria. Swim-up sperm were fixed and subjected to immunocytochemistry and immunoelectronmicroscopy with specific antibodies directed against PAR-2 and EGF-R. Protein extractions from swim-up spermatozoa were analyzed by Western blotting with antibodies for both receptors. Motility of spermatozoa was evaluated by computer-assisted semen analysis. Results： Immunocytochemistry found PAR-2 and EGF-R in approximately 30% of examined human ejaculated spermatozoa. Both receptors were localized in the plasma membrane. Like tryptase, the PAR-2 synthetic agonist SLIGKV reduced sperm motility, and this effect was inhibited by application of two specific EGF-R pathway blockers （AG1478 and PD168393）. Conclusion： The observed reduction of sperm motility by tryptase through the PAR-2 receptor involves EGF-R pathways.

An ab initio Non-Equilibrium Green Function Approach to Charge Transport： Dithiolethine

We present a novel ab initio non-equilibrium approach to calculate the current across a molecular junction. The method rests on a wavefunction-based full ab initio description of the central region of the junction combined with a tight binding approximation for the electrodes in the frame of the Keldysh Green function formalism. Our procedure is demonstrated for a dithiolethine molecule located between silver electrodes. The main conducting channel is identified and the full current voltage characteristic is calculated.

Improved performance of UVC-LEDs by combination of high-temperature annealing and epitaxially laterally overgrown AlN/sapphire

We report on the performance of AlGaN-based deep ultraviolet light-emitting diodes(UV-LEDs)emitting at 265 nm grown on stripe-patterned high-temperature annealed(HTA)epitaxially laterally overgrown(ELO)aluminium nitride(AIN)/sapphire templates.For this purpose,the structural and electro-optical properties of ultraviolet-c light-emitting diodes(UVC-LEDs)on as-grown and on HTA planar AlN/sapphire as well as ELO AlN/sapphire with and without HTA are investigated and compared.Cathodoluminescence measurements reveal dark spot densities of 3.5×10^9 cm^-2,1.1×10^9 cm^-2,1.4×10^9 cm^-2,and 0.9×10^9 cm^-2 in multiple quantum well samples on as-grown planar AIN/sapphire,HTA planar AlN/sapphire,ELO AlN/sapphire,and HTA ELO AlN/sapphire,respectively,and are consistent with the threading dislocation densities determined by transmission electron microscopy(TEM)and high-resolution X-ray diffraction rocking curve.The UVC-LED performance improves with the reduction of the threading dislocation densities(TDDs).The output powers(measured on-wafer in cw operation at 20 mA)of the UV-LEDs emitting at 265 nm were 0.03 mW(planar AlN/sapphire),0.8 mW(planar HTA AlN/sapphire),0.9 mW(ELO AlN/sapphire),and 1.1 mW(HTA ELO AlN/sapphire),respectively.Furthermore,Monte Carlo ray-tracing simulations showed a 15%increase in light-extraction efficiency due to the voids formed in the ELO process.These results demonstrate that HTA ELO AlN/sapphire templates provide a viable approach to increase the efficiency of UV-LEDs,improving both the internal quantum efficiency and the light-extraction efficiency.

Single-photon emission from isolated monolayer islands of InGaN

We identify and characterize a novel type of quantum emitter formed from InGaN monolayer islands grown using molecular beam epitaxy and further isolated via the fabrication of an array of nanopillar structures.Detailed optical analysis of the characteristic emission spectrum from the monolayer islands is performed,and the main transmission is shown to act as a bright,stable,and fast single-photon emitter with a wavelength of~400 nm.