Article
Engineering, Electrical & Electronic
Ishita Bhar, Nirupama Mandal
Summary: This article presents a wireless and passive pressure measurement system based on the principle of inductive-capacitive (LC) sensing. The system uses Velostat and carbon conductive foam as pressure sensing elements, which exhibit changes in resistivity with applied pressure. By modifying the LC circuit into an LCR tank circuit with a variable resistor as a sensing element, pressure can be monitored and measured using a reader coil connected with an impedance analyzer.
IEEE SENSORS JOURNAL
(2022)
Article
Chemistry, Analytical
Tingting Yu, Yebo Tao, Yali Wu, Dongguang Zhang, Jiayi Yang, Gang Ge
Summary: Flexible piezoresistive sensors (FPSs) are widely used in motion detection, wearable electronic devices, and electronic skins due to their compact structure, convenient signal acquisition, and fast dynamic response. However, a single material-based FPS cannot achieve both high sensitivity and a wide measurement range. To address this issue, a heterogeneous multi-material flexible piezoresistive sensor (HMFPS) with high sensitivity and a wide measurement range is proposed. The HMFPS utilizes a graphene foam as the sensing layer for high sensitivity and a PDMS layer as the supporting layer for a large measurement range. The use of heterogeneous multi-material proves to be an effective approach to produce flexible sensors with high performance. The HMFPS-10 demonstrates a sensitivity of 0.695 kPa(-1), a measurement range of 0-14,122 kPa, fast response/recovery (83 ms and 166 ms), and excellent stability (2000 cycles). The potential application of the HMFPS-10 in human motion monitoring is also demonstrated.
Article
Engineering, Electrical & Electronic
Vinod Belwanshi, Sebin Philip, Anita Topkar
Summary: This study designed and fabricated three types of piezoresistive pressure sensors using different process technologies. The sensors were tested under elevated temperature and pressure conditions, and it was found that the sensors with oxide isolated polysilicon piezoresistors demonstrated the best performance.
IEEE SENSORS JOURNAL
(2022)
Article
Chemistry, Analytical
Dhivakar Rajendran, Rajarajan Ramalingame, Saravanan Palaniyappan, Guntram Wagner, Olfa Kanoun
Summary: In this study, flexible and low-cost pressure sensors based on MWCNT/PDMS were designed for foot pressure monitoring. The sensors showed stable response, high sensitivity, and low hysteresis effect. Experimental results demonstrated repeatable responses under different pressure loading rates, showcasing the sensors' potential for accurately measuring foot pressure distribution during activities like walking and standing.
Article
Materials Science, Multidisciplinary
Yijie Xia, Pengju Huang, Xinming Lin, Luchao Wu, Ke Li, Chenming Gao, Gaoyu Zhong
Summary: Flexible pressure sensors, as wearable electronic devices, are environmentally friendly and low-cost, making them suitable for applications in robotic haptics, human-computer interaction, and human pulse wave measurement.
SCIENCE CHINA-MATERIALS
(2023)
Article
Engineering, Electrical & Electronic
Yi Gong, Xiaoying Cheng, Zhenyu Wu, Yisheng Liu, Ping Yu, Xudong Hu
Summary: This paper proposes a novel flexible tactile sensor array for dynamic triaxial force measurement, which shows high sensitivity and response speeds in experiments. The sensor can detect triaxial forces of different magnitudes and frequencies, while also recognizing the shape, size, and curvature of external objects.
IEEE SENSORS JOURNAL
(2021)
Article
Materials Science, Multidisciplinary
Lakhvir Singh, Kamalesh Tripathy, Mitradip Bhattacharjee
Summary: This study presents a flexible PDMS-based pressure sensor with hemispherical microstructures, achieving high sensitivity and operation range. Experiments and simulations show that decreasing the substrate thickness and adding porosity can further improve the sensor performance.
ADVANCED ENGINEERING MATERIALS
(2022)
Article
Engineering, Environmental
Minghui Cao, Jie Su, Shuangqing Fan, Hengwei Qiu, Dongliang Su, Le Li
Summary: Wearable piezoresistive sensors based on three-dimensional graphene offer advantages such as simple preparation, low power consumption, and convenient signal acquisition, showing great potential in applications like human motion detection and health monitoring.
CHEMICAL ENGINEERING JOURNAL
(2021)
Article
Engineering, Electrical & Electronic
Guodong Wang, Jiajia Yan, Xiaofeng Yang, Xinlin Qing
Summary: A resistive pressure sensor based on a composite conductive layer is developed in this paper, using PDMS as the matrix and SAP(+) as the conductive filler. The improved sensor shows significant improvements in sensitivity, response time, and stability.
IEEE SENSORS JOURNAL
(2022)
Article
Chemistry, Multidisciplinary
Jian Li, Ning Li, Yuanyuan Zheng, Dongyang Lou, Yue Jiang, Jiaxi Jiang, Qunhui Xu, Jing Yang, Yujing Sun, Chuxuan Pan, Jianlan Wang, Zhengchun Peng, Zhikun Zheng, Wei Liu
Summary: A facile interfacial locking strategy has been developed to fabricate metal aerogel-based pressure sensors with excellent sensitivity and prominent stability. The sensors have high sensitivity, fast response time, and outstanding durability, making them suitable for real-time monitoring of HMI activities.
Article
Engineering, Electrical & Electronic
Chengwu Gao, Xuanqing Hua, Dacheng Zhang
Summary: In this article, a rapid thermal process is proposed to manufacture piezoresistance for improved performance of piezoresistive devices. An absolute piezoresistive pressure sensor is prepared by anodic bonding between a silicon film and glass with a cavity, resulting in a compact size of 1.0 x 1.0 x 0.513 mm. The piezoresistance arrangement is optimized using the finite element method, and the feasibility of Ti as an oxygen absorber in the anodic bonding process is verified through diaphragm deformation measurement. The pressure sensor prepared using the rapid thermal annealing (RTP) process exhibits an output voltage of 91.6 mV, nonlinearity of 0.14% FSO, temperature coefficient of resistance (TCR) of 571 ppm/degrees C, and temperature coefficient of sensitivity (TCS) of -1676 ppm/degrees C within the pressure range of 0-200 kPa. Compared to the pressure sensor prepared by the common piezoresistive process, the designed sensor shows a reduced TCR by 73% and TCS by 24%, while providing high output voltage, low TCR and TCS, and a small size.
IEEE SENSORS JOURNAL
(2023)
Article
Automation & Control Systems
Jing Li, Tianyu Wu, Huan Jiang, Yanyu Chen, Qibiao Yang
Summary: A facile laser-engraving method was proposed to fabricate a flexible multiwalled-carbon-nanotube/poly(dimethylsiloxane) composite-based piezoresistive sensor with hierarchical microstructures, showing high sensitivity and a wide pressure sensing range. The sensor can monitor subtle pressure changes and has promising applications in wearable electronics.
ADVANCED INTELLIGENT SYSTEMS
(2021)
Article
Materials Science, Multidisciplinary
Zhen Pei, Qiang Zhang, Kun Yang, Zhongyun Yuan, Wendong Zhang, Shengbo Sang
Summary: The developed 3D-printed wearable strain and tactile sensing array integrates flexible strain and pressure sensors with porous structures, providing a wide linear measurement range and continuous pressure monitoring ability for robotic perception.
ADVANCED MATERIALS TECHNOLOGIES
(2021)
Article
Engineering, Electrical & Electronic
Lukang Wang, You Zhao, Yu Yang, Xing Pang, Le Hao, Yulong Zhao, Jiakai Liu
Summary: In this study, femtosecond laser technology was used to fabricate 128 SiC-based piezoresistive pressure sensor diaphragms. The sensors demonstrated accurate pressure measurement performance and good tolerance to temperature, indicating potential for various applications.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2022)
Review
Engineering, Electrical & Electronic
K. Meena, A. Ravi Sankar
Summary: This paper critically reviews biomedical catheters and miniature piezoresistive pressure sensors developed for catheters. The evolution and applications of catheters in measuring physiological parameters are discussed first, followed by the progress of piezoresistive pressure sensors developed for integration with catheters. Alternative recent piezoresistive materials, including silicon nanowire (SNW), carbon nanotube (CNT), and Graphene, are also explored.
IEEE SENSORS JOURNAL
(2021)
Article
Ophthalmology
Joshua Muller, David Alonso-Caneiro, Scott A. Read, Stephen J. Vincent, Michael J. Collins
Summary: This study developed a deep learning model for automatic binarization of choroidal tissue in OCT images from healthy young subjects. The U-Net and SegNet networks showed excellent performance, with over 96% accuracy and high repeatability. These methods offer a useful approach for clinical and research applications.
TRANSLATIONAL VISION SCIENCE & TECHNOLOGY
(2022)
Article
Ophthalmology
Damien Fisher, Michael J. Collins, Stephen J. Vincent
Summary: This study examined the relationship between lens thickness and central corneal edema during short-term open-eye scleral lens wear. It was found that central corneal edema increased with increasing central lens thickness. Theoretical modelling overestimated the effect of lens thickness on corneal edema, especially when the ratio of lens Dk/t was less than 20.
EYE & CONTACT LENS-SCIENCE AND CLINICAL PRACTICE
(2022)
Article
Ophthalmology
Damien Fisher, Michael J. Collins, Stephen J. Vincent
Summary: This study examined the effect of incorporating a single peripheral fenestration on central corneal oedema during short-term open-eye scleral lens wear. Results showed that in healthy corneas, there was no significant difference in central corneal oedema between fenestrated and non-fenestrated high Dk scleral lenses under short-term open-eye conditions when controlling for potential confounding variables.
OPHTHALMIC AND PHYSIOLOGICAL OPTICS
(2022)
Article
Chemistry, Analytical
Ignacio A. Viedma, David Alonso-Caneiro, Scott A. Read, Michael J. Collins
Summary: Optical coherence tomography (OCT) is a valuable tool for diagnosing and monitoring ocular diseases by providing high-resolution cross-sectional images of the eye. This study explores the application of the Mask R-CNN instance segmentation method in retinal OCT image segmentation and compares its performance with commonly used techniques. The results show that the Mask R-CNN is comparable to the U-Net method in segmentation performance, but has the advantage of a simpler boundary extraction process and shorter inference time.
Article
Ophthalmology
Ranjay Chakraborty, Michael J. Collins, Henry Kricancic, Daniel Moderiano, Brett Davis, David Alonso-Caneiro, Fan Yi, Karthikeyan Baskaran
Summary: This study measured the post-illumination pupil response (PIPR) in young adults with different refractive errors using a custom-made optical system. The results showed that refractive error did not have an effect on PIPR, but there was a significant impact of different wavelengths of light stimulation on PIPR.
JOURNAL OF OPTOMETRY
(2022)
Article
Ophthalmology
Ranjay Chakraborty, Michael J. Collins, Henry Kricancic, Brett Davis, David Alonso-Caneiro, Fan Yi, Karthikeyan Baskaran
Summary: This study aimed to examine the effects of stimulation of intrinsically photosensitive retinal ganglion cells (ipRGCs) on axial length changes in young adults. The study found that stimulation of ipRGCs using blue light caused an increase in axial length. However, this effect was not observed in myopic defocus conditions.
JOURNAL OF OPTOMETRY
(2023)
Article
Biology
Yoel F. Garcia-Marin, David Alonso-Caneiro, Damien Fisher, Stephen J. Vincent, Michael J. Collins
Summary: Anterior segment optical coherence tomography (AS-OCT) is a fundamental ophthalmic imaging technique that can provide quantitative metrics for clinical decision making. In this study, a patch-based convolutional neural network (CNN) was used to accurately segment the cornea's boundaries. The performance of the model was assessed based on the number of classes and image quality, revealing comparable results to other established segmentation methods.
COMPUTERS IN BIOLOGY AND MEDICINE
(2023)
Article
Ophthalmology
Vyasa H. H. Bliss, Nathan Branjerdporn, Peng Jia Ooi, Li Mei Teo, Jervis Tu, Justin Yeh, Michael J. J. Collins, Stephen J. J. Vincent
Summary: The aim of this study was to compare the magnitude of corneal oedema induced following short-term reverse piggyback scleral lens wear and standard scleral lens wear. The results showed that the highly oxygen-permeable reverse piggyback system did not induce a clinically or statistically greater magnitude of central corneal oedema compared with standard scleral lens wear.
OPHTHALMIC AND PHYSIOLOGICAL OPTICS
(2023)
Article
Ophthalmology
Rohan P. J. Hughes, Scott A. Read, Michael J. Collins, Stephen J. Vincent
Summary: This study investigates the changes in higher order aberrations and retinal image quality during accommodation in children with different refractive errors. The results show that near work has a greater impact on myopic children, while non-myopic children show greater changes in spherical aberration during accommodation.
OPHTHALMIC AND PHYSIOLOGICAL OPTICS
(2023)
Article
Biochemical Research Methods
Rohan P. J. Hughes, Scott A. Read, Michael J. Collins, Stephen J. Vincent
Summary: This study examined anterior corneal, internal ocular, and total ocular higher order aberrations (HOA's), and retinal image quality in a non-myopic, paediatric cohort. The study found that internal ocular HOA's were higher in magnitude but partially compensated, resulting in reduced levels of HOA's and excellent retinal image quality. Weak correlations were observed between HOA's and age, sex, refractive error, and axial length. These findings provide an improved understanding of the optics and retinal image quality of children's eyes.
BIOMEDICAL OPTICS EXPRESS
(2023)
Article
Multidisciplinary Sciences
Pryntha Rajasingam, Alyra Shaw, Brett Davis, David Alonso-Caneiro, Jared Hamwood, Michael Collins
Summary: Ultraviolet autofluorescence imaging is a useful tool for detecting ocular surface changes caused by sunlight exposure. This study found that the presence of UVAF was associated with changes in tissue thickness, including thinner conjunctival epithelium and thicker sclera. Additionally, participants with only nasal UVAF had significantly thicker temporal conjunctival stroma. These findings highlight the potential of techniques such as tissue thickness measurement and UVAF photography in detecting early UV-related changes to the ocular surface.
SCIENTIFIC REPORTS
(2023)
Article
Ophthalmology
Nasrin Moghadas Sharif, Hosein Hoseini-Yazdi, Ramin Daneshvar, Hema Radhakrishnan, Nasser Shoeibi, Asieh Ehsaei, Michael J. Collins
Summary: The study found small but significant seasonal changes in anterior segment angle parameters, refractive error, and IOP in healthy young adult males, with narrower anterior segment angle dimensions, higher IOP, and more myopic refraction during the winter.
CLINICAL AND EXPERIMENTAL OPTOMETRY
(2023)
Article
Ophthalmology
Asif Iqbal, Damien Fisher, David Alonso-Caneiro, Michael J. Collins, Stephen J. Vincent
Summary: This study quantified the magnitude of corneal edema induced by central and peripheral scleral lenses. The results showed that the levels of corneal edema increased with medium and high fluid reservoir thicknesses. The gradual increase in edema towards the limbus supports the theoretical model without limbal metabolic support.
OPHTHALMIC AND PHYSIOLOGICAL OPTICS
(2023)
Article
Computer Science, Artificial Intelligence
Jason Kugelman, David Alonso-Caneiro, Scott A. Read, Stephen J. Vincent, Michael J. Collins
Summary: Training deep learning methods for OCT retinal and choroidal layer segmentation is challenging due to limited data availability and privacy concerns. This study proposes an enhanced StyleGAN2-based data augmentation method combined with semi-supervised learning using a novel cross-localisation technique. By incorporating styles from unlabelled data with labelled data, the method increases the diversity of synthetic data. Through optimization and targeted model selection, the method demonstrates improved performance in OCT retinal and choroidal layer segmentation.
COMPUTER VISION AND IMAGE UNDERSTANDING
(2023)