Xingsheng Wang

Tissue Cutting With Microserrated Biopsy Punches

This paper investigates the application of bioinspired serrated cutting edges in tissue cutting by biopsy punches (BPs) to reduce the insertion force. BPs are frequently used as a diagnostic tool in many minimally invasive procedures, for both tissue extraction and the delivery of medical fluids. The proposed work is inspired by the mosquito’s maxilla that features microserrations on its cutting edges with the purpose of painlessly puncturing the human skin. The objective of this paper is to study the application of maxillalike microserrations on commercial BPs. The fundamental goal is the minimization of the puncture force at the BP tip during insertion procedures. Microserrations were created on the cutting edge by using a picosecond laser while cutting tests were implemented on a customized testbed on phantom tissue. A reduction of 20–30% in the insertion forces has been achieved with microserrated punches with different texture depths encouraging, thereby, further studies and applications in biomedical devices. Three-dimensional (3D) and two-dimensional (2D) finite element simulations were also developed to investigate the impact of microserrated cutting edges on the stresses in the contact area during soft tissue cutting. [DOI: 10.1115/1.4037726]

APERTURE, a precise extremely-large reflective telescope using re-configurable element: A progress report

One of the pressing needs for the UV-Vis is an affordable design that allows larger mirrors than the JWST primary. In this publication we report the results of the first year of a NASA Innovative Advanced Concepts Phase II study. Our project is called A Precise Extremely large Reflective Telescope Using Reconfigurable Elements (APERTURE). The concept is to deploy a continuous membrane-like mirror. The mirror figure will be corrected after deployment, causing the figure error to decrease below λ/20. While the basic concept is not new, our innovation lies in a different approach to correcting the residual figure errors from the classical piezoelectricpatch technology. Instead, our concept is based on a contiguous coating of a magnetic smart material (MSM). After deployment, a magnetic write head will move along the non-reflecting side of the mirror. The magnetic field will produce a stress in the MSM which then corrects the mirror shape. This publication summarizes the results of minimizing the MSM deposition stress as well as the size and stability of the deformation, which is maintained by a magnetically hard material.