Validation of a new portable system containing both FeNO analysis and spirometry measurement

Introduction

Pulmonary function tests and FeNO measurements are widely used for the diagnosis and management of respiratory diseases. They are used to evaluate airway limitation and respiratory inflammation. Standard spirometers and nitric oxide (NO) analyzers are widely used in hospitals. However, their high price has made some hospitals in underdeveloped areas unable to afford or purchase these devices. The development of a new portable system (SUNVOU TM2125) combining FeNO measurement and spirometry provides additional possibilities for optimizing the diagnosis and management of respiratory diseases. However, its accuracy needs further validation.

Methods

The FeNO analysis component of SUNVOU TM2125 was compared with that of a widely used NO analyzer (NIOX VERO). The spirometry component of the TM2125 was compared with a standard spirometer (Jaeger MasterScreen) for pulmonary parameters such as FEV1, FVC, FEV1/FVC, and PEF. Pearson correlation and Bland-Altman plots were used to evaluate the agreement between the devices.

Results

FeNO values measured using TM2125 were higher than those measured using VERO, with a mean difference of 1.8 ppb. There was a strong correlation between FeNO values measured using the two devices (r = 0.988, p < 0.001). Bland-Altman plots showed a high degree of agreement between the two devices, with 93.3% of values within the 95% confidence interval range. The spirometric parameters (FEV1, FVC, FEV1/FVC, and PEF) measured using the TM2125 were lower than those measured using the MasterScreen. Good correlations were observed between the values measured using the TM2125 and MasterScreen (r > 0.9). Based on the Bland-Altman plots, there was a high degree of agreement between the devices.

Conclusion

The accuracy of FeNO and spirometry measurements using SUNVOU TM2125 was validated. This can help improve the diagnosis and monitoring of chronic respiratory diseases in underdeveloped countries.

A Portable Laser Spectroscopic System for Measuring Nitrous Oxide Emissions on Fertilized Cropland

Nitrous oxide (laughing gas, N2O) is a relevant greenhouse gas. Agriculture contributes significantly to its emissions. As nitrogen fertilization has been identified as one of the main sources of N2O, controlled application and reduction of the amount of fertilizer adapted to crop demand is essential to reduce N2O emissions. This requires detailed studies of the local distribution of the N2O emission fluxes on different croplands. Consequently, frequent spatially resolved field measurements of N2O concentrations are needed. A precision in the ppb range close to the ambient N2O level of 333 ppb is necessary. Tunable laser absorption spectroscopy using quantum-cascade lasers (QCL) as a light source is an established technique for the measurement of N2O traces. We present the development and validation of a compact portable setup for on-site measurement of N2O emissions from the soil. The setup differs from previous solutions by using an interband cascade laser (ICL), which has significantly lower power consumption compared to a QCL. The portable measurement setup allows N2O emission fluxes to be determined with a precision of 3.5% with a measuring duration of 10 min. The developed system enables the detection of increased N2O emissions because of the fertilization of fields. High N2O emission fluxes are indicators of the overfertilization of the field. Directly after fertilization, N2O fluxes between 2.9 and 5.3 µL m-2 min-1 depending on the gas acquisition site are measured during the field tests. Over time, the fluxes decrease. The obtained results compare well with data from more precise but also more complex and maintenance-intensive instruments for atmospheric research. With this system, the soil moisture as well as the air humidity and air temperature are recorded. Strong influences on N2O fluxes by soil moisture were observed. The presented measurement system is a contribution to the establishment of mobile N2O screening systems that are robust in the field and suitable for comprehensive and routine detection of N2O emissions from soil.

Portable TDLAS Sensor for Online Monitoring of CO2 and H2O Using a Miniaturized Multi-Pass Cell

We designed a tunable diode laser absorption spectroscopy (TDLAS) sensor for the online monitoring of CO₂ and H₂O concentrations. It comprised a small self-design multi-pass cell, home-made laser drive circuits, and a data acquisition circuit. The optical and electrical parts and the gas circuit were integrated into a portable carrying case (height = 134 mm, length = 388 mm, and width = 290 mm). A TDLAS drive module (size: 90 mm × 45 mm) was designed to realize the function of laser current and temperature control with a temperature control accuracy of ±1.4 mK and a current control accuracy of ±0.5 μA, and signal acquisition and demodulation. The weight and power consumption of the TDLAS system were only 5 kg and 10 W, respectively. Distributed feedback lasers (2004 nm and 1392 nm) were employed to target CO₂ and H₂O absorption lines, respectively. According to Allan analysis, the detection limits of CO₂ and H₂O were 0.13 ppm and 3.7 ppm at an average time of 18 s and 35 s, respectively. The system response time was approximately 10 s. Sensor performance was verified by measuring atmospheric CO₂ and H₂O concentrations for 240 h. Experimental results were compared with those obtained using a commercial instrument LI-7500, which uses non-dispersive infrared technology. Measurements of the developed gas analyzer were in good agreement with those of the commercial instrument, and its accuracy was comparable. Therefore, the TDLAS sensor has strong application prospects in atmospheric CO₂ and H₂O concentration detection and ecological soil flux monitoring.

A Configurable Monitoring, Testing, and Diagnosis System for Electric Power Plants

The specific equipment, installation and machinery infrastructure of an electric power system have always required specially designed data acquisition systems and devices to ensure their safe operation and monitoring. Besides maintenance, periodical upgrade must be ensured for these systems, to meet the current practical requirements. Monitoring, testing, and diagnosis altogether represent key activities in the development process of electric power elements. This work presents the detailed structure and implementation of a complex, configurable system which can assure efficient monitoring, testing, and diagnosis for various electric power infrastructures, with proven efficiency through a comprehensive set of experimental results obtained in real running conditions. The developed hardware and software implementation is a robust structure, optimized for acquiring a large variety of electrical signals, also providing easy and fast connection within the monitored environment. Its high level of configurability and very good price-performance ratio makes it an original and handy solution for electric power infrastructures.

Backhand-Approach-Based American Sign Language Words Recognition Using Spatial-Temporal Body Parts and Hand Relationship Patterns

Most of the existing methods focus mainly on the extraction of shape-based, rotation-based, and motion-based features, usually neglecting the relationship between hands and body parts, which can provide significant information to address the problem of similar sign words based on the backhand approach. Therefore, this paper proposes four feature-based models. The spatial–temporal body parts and hand relationship patterns are the main feature. The second model consists of the spatial–temporal finger joint angle patterns. The third model consists of the spatial–temporal 3D hand motion trajectory patterns. The fourth model consists of the spatial–temporal double-hand relationship patterns. Then, a two-layer bidirectional long short-term memory method is used to deal with time-independent data as a classifier. The performance of the method was evaluated and compared with the existing works using 26 ASL letters, with an accuracy and F1-score of 97.34% and 97.36%, respectively. The method was further evaluated using 40 double-hand ASL words and achieved an accuracy and F1-score of 98.52% and 98.54%, respectively. The results demonstrated that the proposed method outperformed the existing works under consideration. However, in the analysis of 72 new ASL words, including single- and double-hand words from 10 participants, the accuracy and F1-score were approximately 96.99% and 97.00%, respectively.

Pocket Mercury-Vapour Detection System Employing a Preconcentrator Based on Au-TiO2 Nanomaterials

In environments polluted by mercury vapors that are potentially harmful to human health, there is a need to perform rapid surveys in order to promptly identify the sources of emission. With this aim, in this work, a low cost, pocket-sized portable mercury measurement system, with a fast response signal is presented. It consists of a preconcentrator, able to adsorb and subsequently release the mercury vapour detected by a quartz crystal microbalance (QCM) sensor. The preconcentrator is based on an adsorbing layer of titania/gold nanoparticles (TiO₂NP/AuNPs), deposited on a micro-heater that acts as mercury thermal desorption. For the detection of the released mercury vapour, gold electrodes QCM (20 MHz) have been used. The experimental results, performed in simulated polluted mercury-vapour environments, showed a detection capability with a prompt response. In particular, frequency shifts (-118 Hz ± 2 Hz and -30 Hz ± 2 Hz) were detected at concentrations of 65 µg/m³ Hg⁰ and 30 µg/m³ Hg⁰, with sampling times of 60 min and 30 min, respectively. A system limit of detection (LOD) of 5 µg/m³ was evaluated for the 30 min sampling time.

A Portable Sensor System with Ultramicro Electrode Chip for the Detection of Heavy-Metal Ions in Water

In this study, an ultramicro interdigital electrode array chip (UIEA) was designed and fabricated by using Micro-Electro-Mechanical systems (MEMS) technology, and a portable detection system, using the chip for determination of heavy-metal ions in water, was developed. The working electrode of the UIEA was modified with gold nanoparticles by electrodeposition. The detection sensitivity of the UIEA chip for copper ions was 0.0138 μA·L·μg-1, with the linear range of 0-400 μg/L and the detection limit of 18.89 μg/L (3σ), which was better than that of the compared columnar glassy carbon electrode. The results of the interference experiment verified that the UIEA chip has a certain anti-interference ability against common heavy-metal ions in water, such as Pb2+, Zn2+, and Mg2+ ions. The standard addition method was used to investigate the performance of the developed s ystem for copper ion determination in real water. The recovery range from 87.5% to 94.7% was achieved.

A portable plantar pressure system: Specifications, design, and preliminary results

BACKGROUND

In recent years, there has been an increasing interest in developing in-shoe foot plantar pressure systems. Although such devices are not novel, devising insole devices for gait analysis is still an important issue.

OBJECTIVE

The goal of this study is to develop a new portable system for plantar pressure distribution measurement based on a three-axis accelerometer.

METHODS

The portable system includes: PJRC Teensy 3.6 microcontroller with 32-bit ARM Cortex-M4 microprocessor with a clock speed of 180 MHz; HC-11 radio modules (transmitter and receiver); a battery; a fixing band; pressure sensors; MPU-9150 inertial navigation module; and FFC tape. The pressure insole is leather-based and consists of seven layers. It is divided into 16 areas and the outcome of the system is data concerning plantar pressure distribution under foot during gait. The system was tested on 22 healthy volunteer subjects, and the data was compared with a commercially available system: Medilogic.

RESULT

The SNR value for the proposed sensor is 28.27 dB. For a range of pressure of 30-100 N, the sensitivity is 0.0066 V/N while the linearity error is 0.05. The difference in plantar pressure from both the portable plantar pressure system and Medilogic is not statistically significant.

CONCLUSION

The proposed system could be recommended for research applications both inside and outside of a typical gait laboratory.

Thermo-optic measurements and their inter-dependencies for delineating cancerous breast biopsy tissue from adjacent normal

The histopathological diagnosis of cancer is the current gold standard to differentiate normal from cancerous tissues. We propose a portable platform prototype to characterize the tissue's thermal and optical properties, and their inter-dependencies to potentially aid the pathologist in making an informed decision. The measurements were performed on 10 samples from five subjects, where the cancerous and adjacent normal were extracted from the same patient. It was observed that thermal conductivity (k) and reduced-scattering-coefficient (μ'_s ) for both the cancerous and normal tissues reduced with the rise in tissue temperature. Comparing cancerous and adjacent normal tissue, the difference in k and μ'_s (at 940 nm) were statistically significant (p = 7.94e-3), while combining k and μ'_s achieved the highest statistical significance (6.74e-4). These preliminary results promise and support testing on a large number of samples for rapidly differentiating cancerous from adjacent normal tissues.

A Capacitive 3-Axis MEMS Accelerometer for Medipost: A Portable System Dedicated to Monitoring Imbalance Disorders

The constant development and miniaturization of MEMS sensors invariably provides new possibilities for their use in health-related and medical applications. The application of MEMS devices in posturographic systems allows faster diagnosis and significantly facilitates the work of medical staff. MEMS accelerometers constitute a vital part of such systems, particularly those intended for monitoring patients with imbalance disorders. The correct design of such sensors is crucial for gathering data about patient movement and ensuring the good overall performance of the entire system. This paper presents the design and measurements of a three-axis accelerometer dedicated for use in a device which tracks patient movement. Its main focus is the characterization of the sensor, comparing different designs and evaluating the impact of the packaging and readout circuit integration on sensor operation. Extensive testing and measurements confirm that the designed accelerometer works correctly and allows identifying the best design in terms of sensitivity/stability. Moreover, the response of the proposed sensor as a function of the applied acceleration demonstrates very good linearity only if the readout circuit is integrated in the same package as the MEMS sensor.

A Portable Tunable Diode Laser Absorption Spectroscopy System for Dissolved CO2 Detection Using a High-Efficiency Headspace Equilibrator

Continuous observation of aquatic pCO2  at the ocean surface, with a sensitive response time and high spatiotemporal resolution, is essential for research into the carbon biogeochemical cycle. In this work, a portable tunable diode laser absorption spectroscopy (TDLAS) system for dissolved CO₂ detection in surface seawater, coupled with a home-made headspace equilibrator, allowing real time underway measurements, is described. Both the optical detection part and sample extraction part were integrated together into a compact chamber. An empirical equation suitable for this system was acquired, which can convert the concentration from the gas-phase to the aqueous-phase. A monitoring precision of 0.5% was obtained with time-series measurement, and the detection limits of 2.3 ppmv and 0.1 ppmv were determined with 1 s and 128 s averaging time, respectively. Sampling device used in this work was ameliorated so that the response time of system reduced by about 50% compared to the traditional ‘shower head’ system. The fast response time reached the order of 41 s when the final concentration span was 3079 ppmv. For1902 ppmv, this figure was as short as 20 s. Finally, a field underway measurement campaign was carried out and the results were briefly analyzed. Our work proved the feasibility of the TDLAS system for dissolved CO₂ rapid detection.

A Portable Compact System for Laser Speckle Correlation Imaging of Artworks Using Projected Speckle Pattern

Artworks have a layered structure subjected to alterations caused by various factors. The monitoring of defects at sub-millimeter scale may be performed by laser interferometric techniques. The aim of this work was to develop a compact system to perform laser speckle imaging in situ for effective mapping of subsurface defects in paintings. The device was designed to be versatile with the possibility of optimizing the performance by easy parameters adjustment. The system exploits a laser speckle pattern generated through an optical diffuser and projected onto the artworks and image correlation techniques for the analysis of the speckle intensity pattern. A protocol for the optimal measurement was suggested, based on calibration curves for tuning the mean speckle size in the acquired intensity pattern. The system was validated in the analysis of detachments in an ancient painting model using a short pulse thermal stimulus to induce a surface deformation field and standard decorrelation algorithms for speckle pattern matching. The device is equipped with a compact thermal camera for preventing any overheating effects during the phase of the stimulus. The developed system represents a valuable nondestructive tool for artwork diagnostics, allowing the monitoring of subsurface defects in paintings in out-of-laboratory environment.

A MEMS-Based Multi-Parameter Integrated Chip and Its Portable System for Water Quality Detection

As an important means to protect water resources, water quality detection is of great social and economic significance. Water quality detection sensors processed by micro-electro-mechanical system (MEMS) technology have the advantages of low-cost, small size, and high sensitivity. In this paper, a multi-parameter water quality detection integrated sensor chip is further studied, and a portable detection system using this chip is developed. Temperature, pH, oxidation-reduction potential (ORP), conductivity and concentration of copper ions (Cu²⁺) are selected as typical water quality parameters. Experiments of sensor calibrations using this portable detection system were performed in standard solutions. The sensor has a sensitivity of −57.34 mV/pH in pH detection and 5.95 Ω/°C in temperature response. ORP is directly detected by Pt microelectrode on the chip and the relative error is less than 3%. The electrode constant of the sensor is 1.416 cm⁻¹ and the linearity is 0.9995 in conductivity detection. With the gold nanoparticles deposited on the electrode, the detection peak of Cu²⁺ appears at 280 mV and the sensor shows good linearity to the concentration of Cu²⁺ in the range of 0–0.6 mg/L. The detection limit of Cu²⁺ concentration is 2.33 μg/L. Through measurement and calculation, the accuracy of the portable system is within 4%. This portable multi-parameter water quality detection system with the MEMS-based integrated chip shows great potential in the field and fast detection.

Computer Vision Approach for the Determination of Microbial Concentration and Growth Kinetics Using a Low Cost Sensor System

The measurement of microbial contamination is of primary importance in different fields, from environmental monitoring to food safety and clinical analysis. Today, almost all microbiology laboratories make microbial concentration measurements using the standard Plate Count Technique (PCT), a manual method that must be performed by trained personnel. Since manual PCT analysis can result in eye fatigue and errors, in particular when hundreds of samples are processed every day, automatic colony counters have been built and are commercially available. While quick and reliable, these instruments are generally expensive, thus, portable colony counters based on smartphones have been developed and are of low cost but also not accurate as the commercial benchtop instruments. In this paper, a novel computer vision sensor system is presented that can measure the microbial concentration of a sample under test and also estimate the microbial growth kinetics by monitoring the colonies grown on a Petri dish at regular time intervals. The proposed method has been in-house validated by performing PCT analysis in parallel under the same conditions and using these results as a reference. All the measurements have been carried out in a laboratory using benchtop instruments, however, such a system can also be realized as an embedded sensor system to be deployed for microbial analysis outside a laboratory environment.

Portable System for Neuro-Optical Diagnostics Using Virtual Reality Display

A new product prototype system for diagnosing vision and neurological disorders, called NeuroDotVR, is described herein: this system utilizes a novel wireless NeuroDot brain sensor [Versek C et al. J Neural Eng. 2018 Aug; 15(4):046027] that quantitatively measures visual evoked potentials and fields resulting from custom visual stimuli displayed on a smartphone housed in a virtual reality headset. The NeuroDot brain sensor is unique in that it can be operated both in regular electroencephalography mode, as well as a new electric field encephalography mode, which yields improvements in signal sensitivity and provides new diagnostic information. Steady state and transient visual evoked potentials and fields using reversing checkerboard stimuli are presented with case studies in amblyopia, glaucoma, and dark adaptation. These preliminary data sets highlight potential clinical applications that may be pursued in further product development and scientific studies.

Demonstration of a Low-Cost and Portable Optical Cavity-Based Sensor through Refractive Index Measurements

An optical cavity-based sensor using a differential detection method has been proposed for point-of-care diagnostics. We developed a low-cost and portable optical cavity-based sensor system using a 3D printer and off-the-shelf optical components. In this paper, we demonstrate the sensing capability of the portable system through refractive index measurements. Fabricated optical cavity samples were tested using the portable system and compared to simulation results. A referencing technique and digital low pass filtering were applied to reduce the noise of the portable system. The measurement results match the simulation results well and show the improved linearity and sensitivity by employing the differential detection method. The limit of detection achieved was 1.73 × 10⁻⁵ Refractive Index Unit (RIU), which is comparable to other methods for refractive index sensing.

Portable System for Monitoring and Controlling Driver Behavior and the Use of a Mobile Phone While Driving

There is an utmost requirement for technology to control a driver’s phone while driving, which will prevent the driver from being distracted and thus saving the driver’s and passenger’s lives. Information from recent studies has shown that 70% of the young and aware drivers are used to texting while driving. There are many different technologies used to control mobile phones while driving, including electronic device control, global positioning system (GPS), on-board diagnostics (OBD)-II-based devices, mobile phone applications or apps, etc. These devices acquire the vehicle information such as the car speed and use the information to control the driver’s phone such as preventing them from making or receiving calls at specific speed limits. The information from the devices is interfaced via Bluetooth and can later be used to control mobile phone applications. The main aim of this paper is to propose the design of a portable system for monitoring the use of a mobile phone while driving and for controlling a driver’s mobile phone, if necessary, when the vehicle reaches a specific speed limit (>10 km/h). A paper-based self-reported questionnaire survey was carried out among 600 teenage drivers from different nationalities to see the driving behavior of young drivers in Qatar. Finally, a mobile application was developed to monitor the mobile usage of a driver and an OBD-II module-based portable system was designed to acquire data from the vehicle to identify drivers’ behavior with respect to phone usage, sudden lane changes, and abrupt breaking/sharp speeding. This information was used in a mobile application to control the driver’s mobile usage as well as to report the driving behavior while driving. The application of such a system can significantly improve drivers’ behavior all over the world.

A Fully Integrated Wireless Flexible Ammonia Sensor Fabricated by Soft Nano-Lithography

Flexible ammonia (NH₃) sensors based on one-dimensional nanostructures have attracted great attention due to their high flexibility and low power consumption. However, it is still challenging to reliably and cost-effectively fabricate ordered nanostructure-based flexible sensors. Herein, a smartphone-enabled fully integrated system based on a flexible nanowire sensor was developed for real-time NH₃ monitoring. Highly aligned, sub-100 nm nanowires on a flexible substrate fabricated by facile and low-cost soft lithography were used as sensitive elements to produce impedance response. The detection signals were sent to a smartphone and displayed on the screen in real time. This nanowire-based sensor exhibited robust flexibility and mechanical durability. Moreover, the integrated NH₃ sensing system presented enhanced performance with a detection limit of 100 ppb, as well as high selectivity and reproducibility. The power consumption of the flexible nanowire sensor was as low as 3 μW. By using this system, measurements were carried out to obtain reliable information about the spoilage of foods. This smartphone-enabled integrated system based on a flexible nanowire sensor provided a portable and efficient way to detect NH₃ in daily life.

Portable Drowsiness Detection through Use of a Prefrontal Single-Channel Electroencephalogram

Drowsiness detection has been studied in the context of evaluating products, assessing driver alertness, and managing office environments. Drowsiness level can be readily detected through measurement of human brain activity. The electroencephalogram (EEG), a device whose application relies on adhering electrodes to the scalp, is the primary method used to monitor brain activity. The many electrodes and wires required to perform an EEG place considerable constraints on the movement of users, and the cost of the device limits its availability. For these reasons, conventional EEG devices are not used in practical studies and businesses. Many potential practical applications could benefit from the development of a wire-free, low-priced device; however, it remains to be elucidated whether portable EEG devices can be used to estimate human drowsiness levels and applied within practical research settings and businesses. In this study, we outline the development of a drowsiness detection system that makes use of a low-priced, prefrontal single-channel EEG device and evaluate its performance in an offline analysis and a practical experiment. Firstly, for the development of the system, we compared three feature extraction methods: power spectral density (PSD), autoregressive (AR) modeling, and multiscale entropy (MSE) for detecting characteristics of an EEG. In order to efficiently select a meaningful PSD, we utilized step-wise linear discriminant analysis (SWLDA). Time-averaging and robust-scaling were used to fit the data for pattern recognition. Pattern recognition was performed by a support vector machine (SVM) with a radial basis function (RBF) kernel. The optimal hyperparameters for the SVM were selected by the grind search method so as to increase drowsiness detection accuracy. To evaluate the performance of the detections, we calculated classification accuracy using the SVM through 10-fold cross-validation. Our model achieved a classification accuracy of 72.7% using the PSD with SWLDA and the SVM. Secondly, we conducted a practical study using the system and evaluated its performance in a practical situation. There was a significant difference (* p < 0.05) between the drowsiness-evoked task and concentration-needed task. Our results demonstrate the efficacy of our low-priced portable drowsiness detection system in quantifying drowsy states. We anticipate that our system will be useful to practical studies with aims as diverse as measurement of classroom mental engagement, evaluation of movies, and office environment evaluation.

A Portable Stiffness Measurement System

A new stiffness measurement method is proposed that utilizes the lateral deformation profile of an object under indentation. The system consists of a force measurement module between a pair of equidistant touch sensing modules. Unique feature of the method is that by adjusting the touch module separation, indenter protrusion, and spring constant of the force sensing module, one can choose a desired sensing range for the force module. This feature helps to enhance the stiffness differentiation between objects of similar hardness and avoids measurement saturation. We devised a portable measurement system based on the method, and tested its performance with several materials including polymer foams and human skin.

A High-Performance Portable Transient Electro-Magnetic Sensor for Unexploded Ordnance Detection

Portable transient electromagnetic (TEM) systems can be well adapted to various terrains, including mountainous, woodland, and other complex terrains. They are widely used for the detection of unexploded ordnance (UXO). As the core component of the portable TEM system, the sensor is constructed with a transmitting coil and a receiving coil. Based on the primary field of the transmitting coil and internal noise of the receiving coil, the design and testing of such a sensor is described in detail. Results indicate that the primary field of the transmitting coil depends on the diameter, mass, and power of the coil. A higher mass–power product and a larger diameter causes a stronger primary field. Reducing the number of turns and increasing the clamp voltage reduces the switch-off time of the transmitting current effectively. Increasing the cross-section of the wire reduces the power consumption, but greatly increases the coil’s weight. The study of the receiving coil shows that the internal noise of the sensor is dominated by the thermal noise of the damping resistor. Reducing the bandwidth of the system and increasing the size of the coil reduces the internal noise effectively. The cross-sectional area and the distance between the sections of the coil have little effect on the internal noise. A less damped state can effectively reduce signal distortion. Finally, a portable TEM sensor with both a transmitting coil (constructed with a diameter, number of turns, and transmitting current of 0.5 m, 30, and 5 A, respectively) and a receiving coil (constructed with a length and resonant frequency of 5.6 cm and 50 kHz, respectively) was built. The agreement between experimental and calculated results confirms the theory used in the sensor design. The responses of an 82 mm mortar shell at different distances were measured and inverted by the differential evolution (DE) algorithm to verify system performance. Results show that the sensor designed in this study can not only detect the 82 mm mortar shell within 1.2 m effectively but also locate the target precisely.

Portable system for the detection of micromolar concentrations of glucose

Glucose in non-invasively collected biofluids is generally in the micromolar range and thus, requires sensing methodologies capable of measuring glucose at these levels. Here, we present a small fluorometer system that can quantify glucose in the range of 0-5 μM with resolution of ~0.07 μM. It relies on the glucose binding protein (GBP) fluorescently labeled with two fluorophores. Fluorescence signals from the dual-labeled GBP are utilized in a ratiometric mode, making the measurements insensitive to variations in protein concentration and other systematic errors. Fluorescence is quantified by a miniature, dedicated ratiometric fluorometer that is powered via USB. Concentration is calculated using an ultra-mobile personal computer (UMPC). The whole system is designed to be pocket sized suitable for point-of-care or bedside applications. Test results suggest that the system is a promising tool for accurate measurements of low glucose concentrations (0.1-10 μM) in biological samples.