No abstract

The aim of this study was to evaluate the effects of quarter zona-pellucida (ZP) opening by laser-assisted hatching (QLAH) on the clinical outcomes following transfer of vitrified-warmed blastocysts developed from low-grade cleavage-stage embryos in patients with all high-grade and fair-grade cleavage-stage embryos transferred without achieving pregnancy. Patients were randomized into two groups: QLAH (n=101) and control (n=102). The implantation and clinical pregnancy rates were significantly higher in the QLAH group compared with the control group (P=0.021 and P=0.034, respectively). The live birth rate of the QLAH group was also higher, although not significantly. When the clinical outcomes according to the day of blastocyst vitrification were compared between the groups, the implantation, clinical pregnancy and live birth rates of the QLAH group were significantly higher (P<0.05) than those of the control group for day 6 blastocysts, but not for day 5 or day 5/day 6 blastocysts. These results suggest that QLAH improves the clinical outcomes of vitrified-warmed blastocysts, especially of day 6 vitrified blastocysts, developed from low-grade cleavage-stage embryos.

InGaN/GaN triangular quantum wells (QWs) are investigated theoretically, and the electron-hole wave-function overlap and optical gain characteristics are analyzed. The strong internal piezoelectric field is taken into account to explain the major difference between the optical properties of triangular QWs and conventional rectangular QWs. Our calculations reveal that triangular QWs, in comparison to rectangular QWs, provide higher electron-hole wave-function overlap and are less affected by the quantum confined Stark effect. Furthermore, triangular QWs exhibit increased optical gain and higher polarization degree, which are beneficial to GaN-based light emitting devices.

The structural influences of the laser lift-off (LLO) techniques on the created (0001) GaN surface region are characterized by cross-sectional high-resolution transmission electron microscopy and fitted using the model of stress waves caused by a longitudinal impact at the end of a cylindrical bar extending to infinity. The authors study reveals that, in addition to the superficial damage caused by laser absorption, the stress saltation in GaN crystal where the shock waves come into being induces deformation of the lattices and generates a cluster of half loops above the LLO interface. After that, the lattice deformation will be induced every time the partial dissipation of the steady-state shock waves takes place until the shock wave is dissipated to elastic mode.

We report a detailed study on size-dependent capacitance, especially the negative capacitance (NC), in InGaN-based micro-pixelated light-emitting diodes (μLEDs). Similar to conventional broad-area LEDs, μLEDs show NC under large forward bias. In the conventional depletion and diffusion capacitance regimes, a good linear relationship of capacitance with device size is observed. However, the NC under high forward bias shows slight deviation from above-mentioned linear relationship with device size. This behaviour can be understood if the effects of current density and junction temperature on NC are considered. The measured temperature dependence and frequency dispersion of the capacitance underpin this point of view. The NCs of two reference broad-area LEDs were also measured and compared with that of μLED clusters with the same total size. A stronger NC effect is observed in the μLED clusters, which is attributed to the increased number of sidewall defects during fabrication process