Optical inspection is a rapid and non-destructive method for characterizing the properties of two-dimensional (2D) materials. With the aid of optical inspection, in situ and scalable monitoring of the properties of 2D materials can be implemented industrially to advance the development and progress of 2D material-based devices toward mass production. This review discusses the optical inspection techniques that are available to characterize various 2D materials, including graphene, transition metal dichalcogenides (TMDCs), hexagonal boron nitride (h-BN), group-III monochalcogenides, black phosphorus (BP), and group-IV monochalcogenides. First, the authors provide an introduction to these 2D materials and the processes commonly used for their fabrication. Then they review several of the important structural properties of 2D materials, and discuss how to characterize them using appropriate optical inspection tools. The authors also describe the challenges and opportunities faced when applying optical inspection to recently developed 2D materials, from mechanically exfoliated to wafer-scale-grown 2D materials. Most importantly, the authors summarize the techniques available for largely and precisely enhancing the optical signals from 2D materials. This comprehensive review of the current status and perspective of future trends for optical inspection of the structural properties of 2D materials will facilitate the development of next-generation 2D material-based devices.

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Summary: Transumbilical breast augmentation with pre-filled silicone implants has been performed previously, but technical challenges remain to accommodate more implant options and dissection planes. We aimed to demonstrate the feasibility of transumbilical breast augmentation using various types of pre-filled silicone implants (TUSBA), and its applicability for subglandular, subfascial, dual-plane implantation. In the early stage, TUSBA was primarily performed using endoscope-assisted blunt dissection, and later converted to full endoscopy dissection to achieve better results. Endoscope was used to confirm the pocket and check bleeding for both groups. For endoscope-assisted group, surgical techniques were modified from conventional TUBA. In full endoscopy TUSBA, the entire dissection process was performed under endoscopic monitoring. Preliminary data of patients undergoing TUSBA from June 2016 to April 2021 were retrospectively reviewed. Breast implants with smooth, textured or nanotextured surface properties and round or anatomical shapes were used, with sizes up to 500 mL. Seventy-four patients with mean age 36.4 years (range: 21-55 years) were enrolled in this study. Follow-up ranged from 1 month to 4 years and 6 months (mean: 15.6 months). No excessive postoperative pain in breast or abdomen was reported. Surgery outcomes were aesthetically pleasing in both groups. In the endoscope-assisted group, 3 (4.6%) required major revisional procedures. No revision was required in the full endoscopy group. TUSBA with various types of silicone implants is feasible, and accommodable to all dissection planes. Full endoscopy technique is helpful in reducing the higher complication rate.