Customised joystick-making and training service of power wheelchair using rapid prototyping in rehabilitation centre for people with cervical spinal cord injury: findings from two case studies.

PURPOSE: This study aimed to evaluate the clinical applicability of a customised power wheelchair joystick using rapid prototyping with 3D modeling and printing technology within a rehabilitation centre for patients with cervical spinal cord injury. MATERIALS AND METHODS: Two male participants with tetraplegia following cervical-level spinal cord injury who had difficulty operating a powered wheelchair were recruited. The procedure of the joystick-making and training service consists of four steps: (1) driving evaluation; (2) digital fabrication; (3) functional test; and (4) driving training. K-QUEST 2.0 (Korean-Quebec User Evaluation of Satisfaction version 2.0) was used to measure the usability of the off-the-shelf and customised joystick. RESULTS: During the application process, several redesign stages were required to obtain the final customised joystick. After participants attended a 30-min driving training five times per week for 8 weeks, the usability of the customised joystick was higher than that of the off-the-shelf one. CONCLUSION: Providing the customised joystick-making and training service can be used in hospitalised rehabilitation centre before the hospital discharge of patients and returns to their everyday lives.

3D printing technology in rehabilitation clinics can provide new benefits, including cost-effectiveness, customisation of assistive devices, higher productivity, and enhanced collaboration with clients. More specifically, the entire intervention process, from medical evaluation, designing and manufacturing the devices, and training the client, can be performed efficiently and quickly by rehabilitation practitioners who best understand the client's characteristics.This study aimed to confirm the clinical applicability of a quick and efficient service for a customised power wheelchair joystick using 3D modelling and printing technology in rehabilitation centres for patients with cervical spinal cord injury. This study is expected to provide clinical support for connecting potential users and practitioners with technological advancements.

Effect of undissolved Nb carbides on mechanical properties of hydrogen-precharged tempered martensitic steel.

Nb carbides have attracted significant attention to enhance the resistance of tempered martensitic (TM) steel to hydrogen embrittlement (HE). However, previous studies have elucidated the role of Nb carbides in HE resistance without categorizing their types (i.e., undissolved and newly precipitated). This study focuses on the effect of "undissolved" Nb carbides on the tensile and fatigue properties of hydrogen-precharged TM steels. It validated the following two factors for the HE resistance of the TM steels containing undissolved Nb carbides: hydrogen-trapping by the carbides and refinement of prior austenite grain. The former factor rarely affected the HE resistance owing to the interfacial incoherency between the undissolved carbides and ferritic matrix. Such results are distinguished from previous studies focusing on the newly precipitated carbides. In contrast, the latter factor contributed significantly to the HE resistance via the decrease in hydrogen contents per unit surface of prior austenite grain boundaries.