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Abstract  Both gamma radiation and ozone sensing properties of mixed oxides in the form of thin films are explored. External effects, such as radiation and ozone, cause defects in the materials it interacts with and, consequently, it causes changes in their properties. These changes manifest themselves as the alterations in both the electrical and the optical parameters, which are being measured and employed for dosimetry sensor development. An Edwards E306A thermal coating system was used for In2O3:ZnO:SnO2 (90%:5%:5%) films deposition. For the electrical properties measurements, Cu electrodes were manufactured on the glass substrate via thermal evaporation of Cu; then AZ5214 photoresist was spin-coated over it and exposed to ultraviolet (UV) light via the acetate, containing the desired electrodes patterns. After the exposure, the substrate was placed in Electrolube PDN250ML developer solution and then rinsed in water and placed in the etching solution of SEMO 3207 fine etch crystals to reveal the electrode pattern. The optical properties of In2O3:ZnO:SnO2 thin films were explored using CARY 1E UV–visible spectrophotometer. The values of the optical band gap Eopt are estimated in the view of the Mott and Davis’ theory. Doping of In2O3 with 5% ZnO and 5% SnO2 dramatically changes the overall structure of the film and thus affects its sensing to gamma radiation and ozone. Mixing metal oxides in certain proportions provides a tool for controlling the sensors response. [ABSTRACT FROM AUTHOR]

Abstract  Strain gauges and pressure sensors are necessary tools for automotive, aerospace and biomedical monitoring applications. Of the various types of material, which can be used in their fabrication, oxides allow a degree of flexibility in their design. Furthermore, these devices are more rugged and cost effective than semiconductor sensors and have a higher sensitivity than metal-foil gauges. In this paper, the development of thin and thick film sensors based on oxides such as V2O5, CeO2, Bi2O3, In2O3, RuO2, TiO2, MgO and Nb2O5 is discussed. The devices are evaluated in terms of their sensitivity or gauge factor, linearity, hysteresis and long term stability. Furthermore, different device configurations, planar and sandwich are compared. It is found that the devices presented in this work have sensitivity comparable to that of semiconductor gauges, with good long-term stability. This is particularly true of the sandwich devices. It is observed that oxide based strain gauges may offer an alternative to existing commercial gauges, for example, in applications involving load cells, torque wrenches and limb implants. [ABSTRACT FROM AUTHOR]

The development of a sensor microsystems containing all the components of data acquisition system, such as sensors, signal-conditioning circuits, analog-digital converter, interface circuits and embedded microcontroller (MCU), has become the focus of attention in many biomedical applications. A review of the microsystems technology is presented in this paper, along with a discussion of the recent trends and challenges associated with its developments. A basic description of each sub-system is also given. This includes the different front end, mixed analog-digital, power management, and radio transmitter-receiver circuits. These sub-system designs are presented and discussed in a comparative study and final remarks are made. The performance of each sub-system is assessed regarding many aspects related to the overall system performance. [ABSTRACT FROM AUTHOR]

Thin films of tellurium dioxide (TeO2) and indium oxide (In2O3) mixtures were investigated for γ-radiation dosimetry purpose. Samples were fabricated using thermal vacuum evaporation technique. The electrical properties of mixed oxides thin films [(TeO2)1-x(In2O3)x, where x=0 and 10 per cent by weight] and their changes under the influence of γ-radiation were investigated. Samples with contacts having a planar structure showed increase in the values of current with the increase in radiation dose up to a certain dose level. Thin films in the form of pn-junctions were fabricated with (TeO2)1-x(In2O3)x as p-type material and sulphur as n-type material. These pn-junctions exhibited Zener diode behaviour. The current-voltage characteristics for as-deposited and γ-irradiated samples were recorded. The level of response for all the fabricated devices was found to be highly dependent on the composition of the exposed material. [ABSTRACT FROM AUTHOR]

Biodegradable magnesium-based implants offer mechanical properties similar to natural bone, making them advantageous over nonbiodegradable metallic implants. However, monitoring the interaction between magnesium and tissue over time without interference is difficult. A noninvasive method, optical near-infrared spectroscopy, can be used to monitor tissue's functional and structural properties. In this paper, we collected optical data from an in vitro cell culture medium and in vivo studies using a specialized optical probe. Spectroscopic data were acquired over two weeks to study the combined effect of biodegradable Mg-based implant disks on the cell culture medium in vivo. Principal component analysis (PCA) was used for data analysis. In the in vivo study, we evaluated the feasibility of using the near-infrared (NIR) spectra to understand physiological events in response to magnesium alloy implantation at specific time points (Day 0, 3, 7, and 14) after surgery. Our results show that the optical probe can detect variations in vivo from biological tissues of rats with biodegradable magnesium alloy "WE43" implants, and the analysis identified a trend in the optical data over two weeks. The primary challenge of in vivo data analysis is the complexity of the implant interaction near the interface with the biological medium.

Medical implants made of biodegradable materials are advantageous for short-term applications as fracture fixation and mechanical support during bone healing. After completing the healing process, the implant biodegrades without any long-term side effects nor any need for surgical removal. In particular, Magnesium (Mg) implants, while degrading, can cause physiological changes in the tissues surrounding the implant. The evaluation of structural remodeling is relevant, however, the functional assessment is crucial to provide information about physiological changes in tissues, which can be applied as an early marker during the healing process. Hence, non-invasive monitoring of structural and functional changes in the surrounding tissue during the healing process is essential, and the need for new assessing methods is emerging. This paper provides an assessment of Mg based implants, and an extensive review of the literature is presented with the focus on the imaging techniques for investigation of the Mg implants' biodegradation. The potential of a hybrid analysis, including Near-Infrared Spectroscopy (NIRS) and photoacoustic imaging (PAI) technology, is further discussed. A hybrid solution may play a significant role in monitoring implants and have several advantages for monitoring tissue oxygenation in addition to tissue's acidity, which is directly connected to the Mg implants degradation process. Such a hybrid assessment system can be a simple, ambulant, and less costly technology with the potential for clinically monitoring of Mg implants at site., (Copyright © 2021 IPEM. Published by Elsevier Ltd. All rights reserved.)

Thousands of pollutants are threatening our water supply, putting at risk human and environmental health. Between them, trace metals are of significant concern, due to their high toxicity at low concentrations. Abandoned mining areas are globally one of the major sources of toxic metals. Nowadays, no method can guarantee an immediate response for quantifying these pollutants. In this work, a novel technique based on microwave spectroscopy and planar sensors for in situ real-time monitoring of water quality is described. The sensors were developed to directly probe water samples, and in situ trial measurements were performed in freshwater in four polluted mining areas in the UK. Planar microwave sensors were able to detect the water pollution level with an immediate response specifically depicted at three resonant peaks in the GHz range. To the authors' best knowledge, this is the first time that planar microwave sensors were tested in situ, demonstrating the ability to use this method for classifying more and less polluted water using a multiple-peak approach.

Water quality is one of the most critical indicators of environmental pollution and it affects all of us. Water contamination can be accidental or intentional and the consequences are drastic unless the appropriate measures are adopted on the spot. This review provides a critical assessment of the applicability of various technologies for real-time water quality monitoring, focusing on those that have been reportedly tested in real-life scenarios. Specifically, the performance of sensors based on molecularly imprinted polymers is evaluated in detail, also giving insights into their principle of operation, stability in real on-site applications and mass production options. Such characteristics as sensing range and limit of detection are given for the most promising systems, that were verified outside of laboratory conditions. Then, novel trends of using microwave spectroscopy and chemical materials integration for achieving a higher sensitivity to and selectivity of pollutants in water are described.

Biological water pollution, including organic pollutants and their possible transportation, via biofouling and ballast water, has the potential to cause severe economic and health impacts on society and environment. Current water pollution monitoring methods are limited by transportation of samples to the laboratory for analysis, which could take weeks. There is an urgent need for a water quality monitoring technique that generates real-time data. The study aims to assess the feasibility of three sensing techniques to detect and monitor the concentrations of the model species Tetraselmis suecica in real-time using eleven samples for each method. Results showed UV-Vis spectrophotometer detected increasing concentration of Tetraselmis suecica with R ² = 0.9627 and R ² = 0.9672, at 450 nm and 650 nm wavelengths, respectively. Secondly, low-frequency capacitance measurements showed a linear relationship with increasing concentration of Tetraselmis suecica at 150 Hz ( R ² = 0.8463) and 180 Hz ( R ² = 0.8391). Finally, a planar electromagnetic wave sensor measuring the reflected power S 11 amplitude detected increasing cell density at 4 GHz ( R ² = 0.8019).

Goal: This paper reports a novel electromagnetic sensor technique for real-time noninvasive monitoring of blood lactate in human subjects., Methods: The technique was demonstrated on 34 participants who undertook a cycling regime, with rest period before and after, to produce a rising and falling lactate response curve. Sensors attached to the arm and legs of participants gathered spectral data, blood samples were measured using a Lactate Pro V2; temperature and heart rate data was also collected., Results: Pointwise mutual information and neural networks are used to produce a predictive model. The model shows a good correlation between the standard invasive and novel noninvasive electromagnetic wave based blood lactate measurements, with an error of 13.4% in the range of 0-12 mmol/L., Conclusion: The work demonstrates that electromagnetic wave sensors are capable of determining blood lactate level without the need for invasive blood sampling., Significance: Measurement of blood metabolites, such as blood lactate, in real-time and noninvasively in hospital environments will reduce the risk of infection, increase the frequency of measurement and ensure timely intervention only when necessary. In sports, such tools will enhance training of athletes, and enable more effecting training regimes to be prescribed.

Muscle glycogen levels have a profound impact on an athlete's sporting performance, thus measurement is vital. Carbohydrate manipulation is a fundamental component in an athlete's lifestyle and is a critical part of elite performance, since it can provide necessary training adaptations. This paper provides a critical review of the current invasive and non-invasive methods for measuring skeletal muscle glycogen levels. These include the gold standard muscle biopsy, histochemical analysis, magnetic resonance spectroscopy, and musculoskeletal high frequency ultrasound, as well as pursuing future application of electromagnetic sensors in the pursuit of portable non-invasive quantification of muscle glycogen. This paper will be of interest to researchers who wish to understand the current and most appropriate techniques in measuring skeletal muscle glycogen. This will have applications both in the lab and in the field by improving the accuracy of research protocols and following the physiological adaptations to exercise.

During cutting and processing of meat, the loss of water is critical in determining both product quality and value. From the point of slaughter until packaging, water is lost due to the hanging, movement, handling, and cutting of the carcass, with every 1% of lost water having the potential to cost a large meat processing plant somewhere in the region of €50,000 per day. Currently the options for monitoring the loss of water from meat, or determining its drip loss, are limited to destructive tests which take 24-72 h to complete. This paper presents results from work which has led to the development of a novel microwave cavity sensor capable of providing an indication of drip loss within 6 min, while demonstrating good correlation with the well-known EZ-Driploss method (R² = 0.896).

The specific binding of streptavidin to biotinylated protein A was demonstrated using a microwave detection system. In control experiments, the degree of non-specific binding was negligible. The method of detection was used to monitor the adsorption of two other proteins, cytochrome c and glucose oxidase, on to the IDE microwave sensor surface. The response of the sensor was also examined on different substrate materials, with detection of protein binding observed obtained on both smooth, conductive (gold) and on rough, insulating (hydroxyapatite) surfaces.

This study demonstrates an electromagnetic wave-based sensor embedded within a fluidic cell for the purposes of quantifying Pseudomonas aeruginosa in real time, which implies it could be applied for provision of point-of-care diagnostics. The sensors operates through the interaction of the electromagnetic field with the analyte flowing through the fluidic system, and via the sensor head which has a specifically designed planar pattern to maximize the sensor sensitivity for the given bacteria type. The sensor is demonstrated to respond linearly (R(2) = 0.9942) to OD(550) 25 × 10(-3) - 1.0 bacteria concentration through changing resonant frequency and peak quality factor. This innovative approach is expected to contribute to better provision of healthcare services, minimizing the need for hospital visits through real-time point-of-care diagnostics as opposed to lengthy laboratory assays.

A number of studies have reported improved bone integration for calcium phosphate based materials electrically "poled" by an external electric field prior to implantation. In our study we investigated the effects of electrical polarization of a biphasic ceramic composed of 80% hydroxyapatite and 20% β-tricalcium phosphate. As contact poling involves elevated temperatures as a prerequisite for inducing charge, we used two reference types: samples without any heat treatment and poling, and samples with no poling but heat treatment identical to that of the poled samples. All heat-treated samples (poled or unpoled) showed an improved wettability, which was attributed to a reduced hydrocarbon contamination. Heat treatment alone provoked an accelerated spreading of osteoblast-like cells, whereas on poled samples a retarded cell spreading was observed. While proliferation and several differentiation markers were not influenced by either heat treatment or poling, the release of proinflammatory cytokines interleukin-6 and -8 was significantly reduced for all heat-treated samples, irrespective of additional electrical poling. The study demonstrated that the behaviour of cells in contact with poled biphasic ceramics was influenced by two parameters: heating and charge. Our data revealed that heating of the calcium phosphate ceramics had a much more pronounced effect on cell behaviour than charge., (Copyright © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.)

Food safety is a global health goal and the foodborne diseases take a major crisis on health. Therefore, detection of microbial pathogens in food is the solution to the prevention and recognition of problems related to health and safety. For this reason, a comprehensive literature survey has been carried out aiming to give an overview in the field of foodborne pathogen detection. Conventional and standard bacterial detection methods such as culture and colony counting methods, immunology-based methods and polymerase chain reaction based methods, may take up to several hours or even a few days to yield an answer. Obviously this is inadequate, and recently many researchers are focusing towards the progress of rapid methods. Although new technologies like biosensors show potential approaches, further research and development is essential before biosensors become a real and reliable choice. New bio-molecular techniques for food pathogen detection are being developed to improve the biosensor characteristics such as sensitivity and selectivity, also which is rapid, reliable, effective and suitable for in situ analysis. This paper not only offers an overview in the area of microbial pathogen detection but it also describes the conventional methods, analytical techniques and recent developments in food pathogen detection, identification and quantification, with an emphasis on biosensors., (Copyright 2009 Elsevier Inc. All rights reserved.)

This paper reports on the results from the investigation into the pH sensitivity ofnovel PANI/PVB/PS3 composite films. The conductimetric sensing mode was chosen as itis one of the most promising alternatives to the mainstream pH-sensing methods and it is theleast investigated due to the popularity of other approaches. The films were deposited usingboth screen-printing and a drop-coating method. It was found that the best response to pHwas obtained from the screen-printed thick films, which demonstrated a change inconductance by as much as three orders of magnitude over the pH range pH2-pH11. Thedevices exhibited a stable response over 96 hours of operation. Several films were immersedin buffer solutions of different pH values for 96 hours and these were then investigated usingXPS. The resulting N 1s spectra for the various films confirmed that the change inconductance was due to deprotonation of the PANI polymer backbone. SEM andProfilometry were also undertaken and showed that no considerable changes in themorphology of the films took place and that the films did not swell or contract due toexposure to test solutions.

This paper reviews current state-of-the-art methods of measuring pH levels that are based on polymer materials. These include polymer-coated fibre optic sensors, devices with electrodes modified with pH-sensitive polymers, fluorescent pH indicators, potentiometric pH sensors as well as sensors that use combinatory approach for ion concentration monitoring.

In this work, the pressure sensing properties of polyethylene (PE) and polyvinylidene fluoride (PVDF) polymer films were evaluated by integrating them with a wireless data acquisition system. Each device was connected to an integrated interface circuit, which includes a capacitance to frequency converter (C/F) and an internal voltage regulator to suppress supply voltage fluctuations on the transponder side. The system was tested under hydrostatic pressures ranging from 0 to 17 kPa. Results show PE to be the more sensitive to pressure changes, indicating that it is useful for the accurate measurement of pressure over a small range. On the other hand PVDF devices could be used for measurement over a wider range and should be considered due to the low hysteresis and good repeatability displayed during testing. It is thought that this arrangement could form the basis of a cost-effective wireless monitoring system for the evaluation of environmental or physiological processes.

Present methods for investigation of the GI tract are invasive, distressing for the patient, and give a low diagnostic yield. Wireless, radio telemetry capsules, capable of monitoring physiological changes or visualizing the GI tract are noninvasive and could realize a faster time to diagnoses along with improved treatment of both organic diseases and functional disorders. Consequently, the patient's quality of life would improve. In this paper, early radiotelemetry capsules and the motivating factors for their development are discussed. Following this, prototype and commercially available digestible microsystems making use of microelectronics and microelectromechanical systems are presented. It is shown that these capsules have the potential to combine the functions of their predecessors and furthermore can be used for visualizing the gastrointestinal tract. These systems have the potential to improve diagnostic yield and, in the future, treatment of disease using these capsules should become a reality.

Telemetry capsules have existed since the 1950s and were used to measure temperature, pH or pressure inside the gastrointestinal (GI) tract. It was hoped that these capsules would replace invasive techniques in the diagnosis of function disorders in the GI tract. However, problems such as signal loss and uncertainty of the pills position limited their use in a clinical setting. In this paper, a review of the capabilities of MicroElectroMechanical Systems (MEMS) and thick film technology (TFT) for the fabrication of a wireless pressure sensing microsystem is presented. The circuit requirements and methods of data transfer are examined. The available fabrication methods for MEMS sensors are also discussed and examples of wireless sensors are given. Finally the limitations of each technology are examined.