ABSTRACT
This paper proposed a novel real-time compression load measurement system for a kayaking paddle based on optical fiber technology. The optical fiber sensor, fiber Bragg grating, is embedded in a 2 mm polydimethylsiloxane membrane, which serves as a pressure mat that can be easily attached/detached to/from the kayaking paddle. The proposed system is proposed for measuring and evaluating both handgrip loading and paddle blade load distribution during on-water kayaking, e.g., peak compression load distribution pattern and duration of the paddle blade in real time. Both indoor prototype experiment results and on-water experimental data on an expert paddler were presented to demonstrate the application potential of the proposed system.
ABSTRACT
A biocompatible fiber-optic pH sensor based on a unique double-pass Mach-Zehnder interferometer is proposed. pH responsive poly(2-hydroxyethyl methacrylate-co-2-(dimethylamino)ethyl methacrylate) hydrogel coating on the fiber swells/deswells in response to local pH, leading to refractive index changes that manifest as shifting of interference dips in the optical spectrum. The pH sensor is tested in spiked phosphate buffer saline and demonstrates high sensitivity of 1.71 nm/pH, pH 0.004 limit of detection with good responsiveness, repeatability, and stability. The proposed sensor has been successfully applied in monitoring the media pH in cell culture experiments to investigate the relationship between pH and cancer cell growth.
Subject(s)
Fiber Optic Technology/instrumentation , Interferometry/instrumentation , Cell Line, Tumor , Equipment Design , Extracellular Space/chemistry , Humans , Hydrogel, Polyethylene Glycol Dimethacrylate/chemistry , Hydrogen-Ion Concentration , Interferometry/methods , Limit of Detection , Linear ModelsABSTRACT
A highly sensitive miniature photonic crystal fiber refractive index sensor based on field mode excitation is presented. The sensor is fabricated by melting one end of a photonic crystal fiber into a rounded tip and splicing and collapsing the other end with a single-mode fiber. The rounded tip is able to induce cladding mode excitation, which resulted in an additional phase delay. Linear response of 262.28 nm/refractive index unit in the refractive index range of 1.337 to 1.395 is obtained for the physical length of a 953 µm sensor. The sensor is also shown to be insensitive to environmental temperature.
Subject(s)
Miniaturization/instrumentation , Optical Fibers , Interferometry , Spectrum AnalysisABSTRACT
Perfectly aligned arrays of single-crystalline silicon nanowires were fabricated using top-down CMOS-compatible techniques. We demonstrate that these nanowire devices are able to detect adipocytokines secreted by adipose cells with femtomolar sensitivity, high specificity, wide detection range, and ability for parallel monitoring. The nanowire sensors also provide a novel tool to reveal the poorly understood signaling mechanisms of these newly recognized signaling molecules, as well as their relevance in common diseases such as obesity and diabetes.
