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Your search keyword '"Ngan, Alfonso Hing Wan"' showing total 21 results
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21 results on '"Ngan, Alfonso Hing Wan"'

5. A Battery‐Free Low‐Cost Paper‐Based Microfluidic Actuator.

Author

Kwan, Kin Wa, Wu, Runni, Li, Wei, Yin, Yuyang, Chen, Xiaodie, and Ngan, Alfonso Hing Wan

Subjects
ACTUATORS, POWER resources, MEDICAL equipment, MICROFLUIDICS, MICROFLUIDIC devices
Abstract

This study presents a novel approach to create a low‐cost and user‐friendly water‐induced actuator based on hydrophobic papers and a simple embossing method. By injecting water onto the papers through microfluidic channels made by embossing, fast and reversible bending actuation can be induced. The actuation angle and speed are dependent on the amount and duration of the water applied, which allows the actuator to be effectively controlled by syringe injection/drawing without the need for an external power supply. A bending angle of >90° can be achieved in ≈15 s, with complete reversal attainable in ≈3 min; and the actuation can be induced again by resting for ≈1 h after the reversal. This work represents a significant contribution to the field of paper‐based microfluidics by demonstrating actuation in a battery‐free, low‐cost, and simple approach, with potential applications in paper‐based analytical devices such as medical diagnostics. [ABSTRACT FROM AUTHOR]

Published
2024
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21. Nanomechanics of Bone and Bioactive Bone-Cement Interfaces.

Author

Ling Qin, Genant, Harry K., Griffith, James F., Kwok Sui Leung, Guo-Xin Ni, Lu, William Wei-Jia, Ngan, Alfonso Hing-Wan, and Luk, Keith Dip-Kei

Abstract

Nanoindentation is an ideal technique to investigate mechanical behaviour at the bone/implant interface. A viscoelasticity correction method was developed and validated for use on biological specimens. Using this new technique the nanomechanics of the interface between strontium-containing hydroxyapatite (Sr-HA) bone cement with cancellous and cortical bone were investigated under weight-bearing conditions. At 6 months after implantation, Young's modulus and hardness at the interface between cancellous bone and Sr-HA cement were significantly higher than those at the cancellous bone and Sr-HA cement, whereas Young's modulus and hardness at interface between cortical bone and Sr-HA cement were significantly lower than those at cortical bone, but significantly higher than Sr-HA cement These results were supported by histological observation and chemical composition. Osseointegration of Sr-HA cement with cancellous bone was observed. An apatite layer with a high content of calcium and phosphorus was found between cancellous bone and Sr-HA cement; however, no such apatite layer was observed at the interface between cortical bone and Sr-HA cement. And the contents of calcium and phosphorus of the interface were lower than those of cortical bone. The mechanical properties indicated that these two interfaces were diffused interfaces, and cancellous bone or cortical bone was grown into Sr-HA cement 6 months after the implantation. [ABSTRACT FROM AUTHOR]

Published
2007
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