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We investigate the effect of ozone (O3) oxidation of silicon carbide (SiC) on the flat-band voltage (V fb) stability of SiC metal–oxide–semiconductor (MOS) capacitors. The SiC MOS capacitors are produced by O3 oxidation, and their V fb stability under frequency variation, temperature variation, and bias temperature stress are evaluated. Secondary ion mass spectroscopy (SIMS), atomic force microscopy (AFM), and x-ray photoelectron spectroscopy (XPS) indicate that O3 oxidation can adjust the element distribution near SiC/SiO2 interface, improve SiC/SiO2 interface morphology, and inhibit the formation of near-interface defects, respectively. In addition, we elaborate the underlying mechanism through which O3 oxidation improves the V fb stability of SiC MOS capacitors by using the measurement results and O3 oxidation kinetics.

To compare keratocyte activation, cellular morphologic changes and wound healing after SMILE and PRK procedures using transmission electron microscope (TEM).In this study, 22 New Zealand white rabbits (10- to 15-week old) were used. The right eyes of all animals underwent SMILE procedure and the left eyes underwent PRK procedure. Cornea samples taken 1 day and 1 week postoperatively were examined using TEM.Using TEM 1 day after SMILE procedure, the organization of collagen fibers seemed to have been preserved without thermal alterations. Keratocyte activation was observed in the anterior stroma. Disrupted collagen arrangement and debris of cells are visible in the area of damage, and some phagocytic cells and a large number of secondary lysosomes are visible in those cells. At the perimeter zone of the interface, many coenocytes and collagen fragments could be found within the phagocytic cell. One week after SMILE procedure, potential lacuna could be discerned. A large part of the interface of the lenticule extracted had an appearance of clearly being adhered to some mucus secretions. One day after PRK procedure, an irregular epithelial surface was visible using TEM. Keratocytes had been activated and the rough endoplasmic reticulum in those cells had expanded. One week after PRK procedure, the epithelial surface still was irregular and keratinization of the epithelium was still visible in some areas. Corneal endothelium cells were mildly damaged and some vacuoles within the cytoplasm could be discerned. In the anterior stroma, some unhealthy activated keratocytes could still be observed. New collagen fibrils were found present near the activated keratocytes.Using TEM, keratocyte activation could still be observed after SMILE compared to after PRK procedure. Fewer cellular ultrastructural changes were seen after SMILE procedure. Unlike in PRK procedure, no damaged epithelium and endothelium were found after SMILE.

To evaluate and compare the recovery of central and peripheral corneal sensitivity in the early period after small incision lenticule extraction (SMILE) and femtosecond lenticule extraction (FLEx).In this study, 47 cases (87 eyes) which underwent SMILE and FLEx were included. Central, superior, inferior, nasal and temporal corneal sensitivity was measured using a Cochet-Bonnet esthesiometer (Luneau Ophthalmologic) before and 1 week, 1 month, and 3 months after SMILE and FLEx. The results were analyzed with Mann-Whitney test by SPSS13.0 software.There were statistical differences between SMILE and FLEx group in the central, inferior, nasal and temporal corneal sensitivity at 1 week, 1 month and 3 months postoperatively (Z = -5.219, -7.120, -6.735, -7.139, -5.945, -6.644, -7.006, -7.121, -5.262, -3.086, -4.140, -3.523. P0.01). However, the superior corneal sensitivity in the SMILE group did not show significant difference (Z = -1.807, P = 0.071) as compared to FLEx group (with exception of 1 week postoperatively). At 1 month and 3 months postoperatively, corneal sensitivity in the superior quadrant were (5.23 ± 0.62) and (5.57 ± 0.57) cm in the SMILE group, and were (4.43 ± 1.20) and (4.85 ± 1.11) cm in the FLEx group. There were statistical differences between these two groups (Z = -2.935, -2.678. P = 0.003, 0.007). In the SMILE group, corneal sensitivity in the central, superior, inferior, nasal and temporal quadrants at 3 months postoperatively was (5.74 ± 0.51), (5.57 ± 0.57), (5.70 ± 0.55), (5.83 ± 0.37), (5.84 ± 0.30) cm respectively, there were no significant differences as compared with preoperative data (Z = -1.255, -0.893, -0.570, -0.630, -0.935. P = 0.209, 0.440, 0.569, 0.529, 0.350). In the FLEx group, corneal sensitivity in the superior at 3 months postoperatively was 4.85 ± 1.11, there was not significant difference compared with preoperative data (Z = -1.095, P = 0.272). There were no correlations between the changes of central corneal sensitivity and central corneal ablation depth, central corneal thickness and preoperative spherical equivalent (SMILE group: r = 0.159, -0.202, 0.106, 0.060. P0.05. FLEx group: r = -0.156, -0.059, 0.058, -0.005. P0.05) after SMILE and FLEx surgery.Corneal sensitivity decreases after SMILE and FLEx, and then returns to its original state over time. The decrease of corneal sensitivity after the SMILE was fewer and the recovery was faster as compared with FLEx.

To compare the biomechanical properties of the cornea after small-incision lenticule extraction (lenticule extraction group) with those after femtosecond laser-assisted laser in situ keratomileusis (femtosecond LASIK group).Tianjin Eye HospitalEye Institute, Tianjin Key Laboratory of Ophthalmology and Visual Science, Tianjin Medical University, Tianjin, China.Prospective comparative case series.Corneal hysteresis (CH), the corneal resistance factor (CRF), and 37 other biomechanical waveform parameters were quantitatively assessed with the Ocular Response Analyzer preoperatively and 1 week and 1, 3, and 6 months postoperatively.Each group comprised 40 eyes. The decrease in CH and the CRF was statistically significant 1 week postoperatively compared with preoperatively in both groups (P.0001). However, the CH and CRF values in the lenticule extraction group were significantly higher than those in the femtosecond LASIK group 3 months and 6 months postoperatively (P.032). The residual stromal thickness index versus the CRF and CH and the planned lenticule thickness versus the change in central corneal thickness were statistically significant in the lenticule extraction group (r = 0.388 to 0.950, P.018); no significant correlation was found in the femtosecond LASIK group. In the waveform analysis of the lenticule extraction group, 28 of the 37 biomechanical waveform parameters differed significantly between preoperative values and postoperative values (P.035).Both small-incision lenticule extraction and femtosecond laser-assisted LASIK can cause biomechanical changes in the cornea. However, changes in the cornea's viscoelastic properties were less after lenticule extraction than after LASIK.No author has a financial or proprietary interest in any material or method mentioned.