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Ahmed M M Almassri, Wan Zuha Wan Hasan, Siti Anom Ahmad, Suhaidi Shafie, Chikamune Wada, Keiichi Horio
This paper presents a novel approach to predicting self-calibration in a pressure sensor using a proposed Levenberg Marquardt Back Propagation Artificial Neural Network (LMBP-ANN) model. The self-calibration algorithm should be able to fix major problems in the pressure sensor such as hysteresis, variation in gain and lack of linearity with high accuracy. The traditional calibration process for this kind of sensor is a time-consuming task because it is usually done through manual and repetitive identification...
August 5, 2018: Sensors
Jingxing Guo, Ying Liu, Yunlong Chen, Jianqi Li, Huangxian Ju
Quorum sensing (QS) is crucial for bacterial survival and activity. Although detecting related signaling metabolites can reveal QS, a versatile platform for convenient real-time imaging of their secretion in the context of bacterial biofilms along with inhibition to the growth of biofilms is still highly desired. Here we develop a flexible sticky note with a sandwich structure by encapsulating gold nanostars between two pieces of hexagonal boron nitride layers, which can be easily pasted on natural biofilms to monitor in real-time the secreted signaling molecule by SERS imaging with high sensitivity and spatiotemporal resolution...
July 21, 2018: Chemical Science
Kang Shao, Biru Wang, Axiu Nie, Shiyi Ye, Jing Ma, Zhonghua Li, Zhicheng Lv, Heyou Han
Signal-amplified ratiometric electrochemiluminescence (Sa-RECL) provides an attractive approach to maximize signal-to-noise ratio through enhancing signals and eliminate interferences. In this work, we prepared a novel metal-organic framework (MOF)/Au/G-quadruplex as both quenchers and enhancers to fabricate a target-triggered ratiometric ECL sensor for high sensitive and accurate detection of prostatic specific antigen (PSA). The ratiometric ECL sensor using the dual-potential-dependent ECL emitters (quantum dots (QDs) and luminol) and MOF/Au/G-quadruplex not only achieved signal self-calibration but also realized cooperative amplification...
July 17, 2018: Biosensors & Bioelectronics
Zhenyi Gao, Bin Zhou, Bo Hou, Chao Li, Qi Wei, Rong Zhang
Angle position sensors (APSs) usually require initial calibration to improve their accuracy. This article introduces a novel offline self-calibration scheme in which a signal flow network is employed to reduce the amplitude errors, direct-current (DC) offsets, and phase shift without requiring extra calibration instruments. In this approach, a signal flow network is firstly constructed to overcome the parametric coupling caused by the linearization model and to ensure the independence of the parameters. The model parameters are stored in the nodes of the network, and the intermediate variables are input into the optimization pipeline to overcome the local optimization problem...
August 1, 2018: Sensors
Zhiliang Luo, Ruibing An, Deju Ye
γ-Glutamyltranspeptidase (GGT) is a cell membrane-bound protease that participates in cellular glutathione and cysteine homeostasis, closely relating to many physiological and pathological processes. The accurate measurement of GGT activity is useful for the early diagnosis of diseases. In the past few years, many efforts have been made to build optical imaging probes for the detection of GGT activity both in vitro and in vivo. In this Minireview paper, we summarize the recent advances in the development of various optical imaging probes for GGT, including activatable fluorescence probes, ratiometric fluorescence probes and activatable bioluminescence probes...
July 30, 2018: Chembiochem: a European Journal of Chemical Biology
Zang Chen, Jizhou Lai, Jianye Liu, Rongbing Li, Guotian Ji
The GNSS/INS (Global Navigation Satellite System/Inertial Navigation System) navigation system has been widely discussed in recent years. Because of the unique INS-aided loop structure, the deeply coupled system performs very well in highly dynamic environments. In practice, vehicle maneuvering has a big influence on the performance of IMUs (Inertial Measurement Unit), and determining whether the selected IMUs and receiver parameters satisfy the loop dynamic requirement is still a critical problem for deeply coupled systems...
July 18, 2018: Sensors
Arman A Kahokehr, Michael A Granieri, George D Webster, Andrew C Peterson
INTRODUCTION: To evaluate the management of recurrence after urethroplasty for bulbar urethral stricture disease (BUSD) at our institution. METHODS: We performed an institution review board approved retrospective case study of our urethroplasty database to collect stricture-related and post-operative information with emphasis on recurrence after urethroplasty for BUSD between 1996-2012. Repair types included primary anastomotic, augmented anastomotic and onlay. Recurrence was defined as the need for intervention and diagnosed with cystoscopy or retrograde urethrogram...
July 13, 2018: Journal of Urology
Michael Kellman, Francois Rivest, Alina Pechacek, Lydia Sohn, Michael Lustig
We present a novel method to perform individual particle (e.g. cells or viruses) coincidence correction through joint channel design and algorithmic methods. Inspired by multiple-user communication theory, we modulate the channel response, with Node-Pore Sensing, to give each particle a binary Barker code signature. When processed with our modified successive interference cancellation method, this signature enables both the separation of coincidence particles and a high sensitivity to small particles. We identify several sources of modeling error and mitigate most effects using a data-driven self-calibration step and robust regression...
April 15, 2018: IEEE Sensors Journal
Kang Gao, Shunqing Ren, Xijun Chen, Zhenhuan Wang
For a running freely land-vehicle strapdown inertial navigation system (SINS), the problems of self-calibration and attitude alignment need to be solved simultaneously. This paper proposes a complete alignment algorithm for the land vehicle navigation using Inertial Measurement Units (IMUs) and an odometer. A self-calibration algorithm is proposed based on the global observability analysis to calibrate the odometer scale factor and IMU misalignment angle, and the initial alignment and calibration method based on optimal algorithm is established to estimate the attitude and other system parameters...
June 28, 2018: Sensors
Yi-Jia Du, Ting-Ting Yang, Dong-Dong Gong, Yi-Cheng Wang, Xiang-Yu Sun, Feng Qin, Gang Dai
The scale factor drifts and other long-term instability drifts of Micro-Electro-Mechanical System (MEMS) inertial sensors are the main contributors of the position and orientation errors in high dynamic environments. In this paper, a novel high dynamic micro vibrator, which could provide high acceleration and high angular rate rotation with integrated optical displacement detector, is proposed. Commercial MEMS inertial sensors, including 3-axis accelerometer and 6-axis inertial measurement unit which is about 3 mm * 3 mm * 1 mm with 19 mg, could be bonded on the vibration platform of the micro vibrator to perform in-situ during the self-calibration procedure...
June 27, 2018: Sensors
Ozlem Yavas, Srdjan S Aćimović, Jose Garcia-Guirado, Johann Berthelot, Paulina Dobosz, Vanesa Sanz, Romain Quidant
The need for point-of-care devices able to detect diseases early and monitor their status, out of a lab environment, has stimulated the development of compact biosensing configurations. Whereas localized surface plasmon resonance (LSPR) sensing integrated into a state-of-the-art microfluidic chip stands as a promising approach to meet this demand, its implementation into an operating sensing platform capable of quantitatively detecting a set of molecular biomarkers in an unknown biological sample is only in its infancy...
July 11, 2018: ACS Sensors
Do-Hyun Kim, Robert James, Don Calogero, Ilko K Ilev
We present a fiber-optic dual-confocal laser caliper method for noncontact high-precision sensing and measuring thickness and refractive index of intraocular lens (IOL) implants. The principle of the method is based on sensing and measuring the confocal intensity response of the laser beam reflection from the opposite object surfaces, which provides the advanced feature of having no limitations on the object shape, thickness, and transparency. Using single-mode optical fibers and a 658-nm laser source, the thickness measurement accuracy was assessed to be as high as 5  μm...
June 2018: Journal of Biomedical Optics
Robert Kuschmierz, Elias Scharf, Nektarios Koukourakis, Jürgen W Czarske
Coherent fiber bundle (CFB)-based endoscopes enable optical keyhole access in applications such as biophotonics. In conjunction with objective lenses, CFBs allow imaging of intensity patterns. In contrast, digital optical phase conjugation enables lensless holographic endoscopes for the generation of pixelation-free arbitrary light patterns. For real-world applications, however, this requires a non-invasive in situ calibration of the complex optical transfer function of the CFB with only single-sided access...
June 15, 2018: Optics Letters
Josefin Hartmann, Florian Distler, Martin Baumüller, Ewald Guni, Sascha Pahernik, Michael Wucherer
BACKGROUND: Due to new radiobiologic data, the International Commission on Radiological Protection recommends a dose limit of 20 mSv per year to the eye lens. Therefore, the IAEA International Basic Safety Standard and the European council directive 2013/59/EURATOM require a reduction of the annual dose limit from 150 to 20 mSv. Urologists are exposed to an elevated radiation exposure in the head region during fluoroscopic interventions, due to the commonly used overtable X-ray tubes and the rarely used radiation protection for the head...
July 16, 2018: Journal of Endourology
Xiaolu Li, Yunye Li, Xinhao Xie, Lijun Xu
Systematic errors generated from internal misalignments of a lab-built terrestrial laser scanner (TLS) need to be calibrated to improve the positional accuracy of point-cloud. Hence, an angle measurement error model was established by the ray-tracing method involving five types of mounting angle errors, which were estimated by two-face method and network method. Experimental results show that the two errors including mirror tilt error and vertical index offset error are regarded as main systematic errors for lab-built TLS, and consequently the positional accuracy of the point-cloud can be improved in horizontal and vertical directions...
May 28, 2018: Optics Express
Jin Li, Zilong Liu
Internal parameter calibration of remote sensing cameras (RSCs) is a necessary step in remote sensing photogrammetry. On-orbit camera calibration widely adopts external ground control points (GCPs) to measure its internal parameters. However, accessible and available GCPs are not easy to achieve when cameras work on a satellite platform. In this paper, we propose an efficient camera self-calibration method using a micro-transceiver in conjunction with deep learning. A supervised learning set is produced by the micro-transceiver, where multiple two-dimensional diffraction grids are produced and transformed into multiple auto-collimating sub-beams equivalent to infinite target-point training examples...
May 28, 2018: Optics Express
Suejit Pechprasarn, Terry W K Chow, Michael G Somekh
In this paper, we present a direct method to measure surface wave attenuation arising from both ohmic and coupling losses using our recently developed phase spatial light modulator (phase-SLM) based confocal surface plasmon microscope. The measurement is carried out in the far-field using a phase-SLM to impose an artificial surface wave phase profile in the back focal plane (BFP) of a microscope objective. In other words, we effectively provide an artificially engineered backward surface wave by modulating the Goos Hänchen (GH) phase shift of the surface wave...
June 4, 2018: Scientific Reports
Jinhai Cai, Pankaj Kumar, Joshua Chopin, Stanley J Miklavcic
In this paper we report on an automated procedure to capture and characterize the detailed structure of a crop canopy by means of stereo imaging. We focus attention specifically on the detailed characteristic of canopy height distribution-canopy shoot area as a function of height-which can provide an elaborate picture of canopy growth and health under a given set of conditions. We apply the method to a wheat field trial involving ten Australian wheat varieties that were subjected to two different fertilizer treatments...
2018: PloS One
Gregory M Palmer, Hengtao Zhang, Chen-Ting Lee, Husam Mikati, Joseph A Herbert, Marlee Krieger, Jesko von Windheim, Dave Koester, Daniel Stevenson, Daniel J Rocke, Ramon Esclamado, Alaatin Erkanli, Nirmala Ramanujam, Mark W Dewhirst, Walter T Lee
Diffuse reflectance spectroscopy (DRS) represents a quantitative, noninvasive, nondestructive means of assessing vascular oxygenation, vascularity, and structural properties. However, it is known that such measurements can be influenced by the effects of pressure, which is a major concern for reproducible and operator-independent assessment of tissues. Second, regular calibration is a necessary component of quantitative DRS to account for factors such as lamp decay and fiber bending. Without a means of reliably controlling for these factors, the accuracy of any such assessments will be reduced, and potentially biased...
May 2018: Journal of Biomedical Optics
Rabi Chhantyal-Pun, Alexander Valavanis, James T Keeley, Pierluigi Rubino, Iman Kundu, Yingjun Han, Paul Dean, Lianhe Li, A Giles Davies, Edmund H Linfield
We demonstrate a gas spectroscopy technique, using self-mixing in a 3.4 terahertz quantum-cascade laser (QCL). All previous QCL spectroscopy techniques have required additional terahertz instrumentation (detectors, mixers, or spectrometers) for system pre-calibration or spectral analysis. By contrast, our system self-calibrates the laser frequency (i.e., with no external instrumentation) to a precision of 630 MHz (0.02%) by analyzing QCL voltage perturbations in response to optical feedback within a 0-800 mm round-trip delay line...
May 15, 2018: Optics Letters
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