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[IEEE 2018 48th European Microwave Conference (EuMC) - Madrid, Spain (2018.9.23-2018.9.27)] 2018 48th European Microwave Conference (EuMC) - Pulse-Distortion Analysis for Millimeter-Wave Time-Domain Material Identification
摘要： Analyzing the frequency dependent dielectric properties can be used to identify and distinguish materials in biomedical instruments. In the millimeter-wave range, the dielectric properties of biological tissues are mainly determined by their water content. For instance, it has been shown, that cancer cells have a lower water content than healthy skin cells, resulting in a significant dielectric contrast between them. In this work, we analyze the pulse distortion observed in measurements of the millimeter-wave reflection of water and porcine skin. We propose to use the distortion caused by the frequency dependent reflection coefficient at the interface of a material as a feature for identification. Using a simplified model for the reflection coefficient of the material under test, we simulate the distortion caused by the frequency dispersion. In simulation as well as in measurement, we observe different startup transients depending on the dispersion properties of a material under test. The startup behavior can therefore be used as feature, to directly identify dispersive materials in the time domain.
关键词： Dielectric,Time-domain analysis,Electromagnetic,Biomedical,Measurements,Characterization,Measurement,Pulse,Wavelet Generator,Reflection
更新于2025-09-04 15:30:14
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Reactive Species Detection in Biology || UV–Vis Absorption and Chemiluminescence Techniques
摘要： Spectrophotometric techniques involving ultraviolet and colorimetric detection offer a convenient way of detecting reactive species (RS) formation due to the prevalence of UV-Vis spectrophotometer in research laboratories. Conventional spectrophotometric measurement of RS exploits their unique chemical reactivity with a small organic molecule and/or enzyme that has specificity to these RS where formation (or disappearance) of absorption peak/s at a particular wavelength is observed at the UV to the visible region of the electromagnetic spectrum. Direct detection of O2 from xanthine oxidase in the past involves rapid-freeze technique using electron paramagnetic resonance (EPR) spectroscopy. At the same time, spectrophotometric detection of O2 generated from xanthine oxidase/xanthine system was also employed for the investigation of the enzymatic property of superoxide dismutase (SOD) where the O2 levels were measured through reduction of ferricytochrome c, tetranitromethane, or oxidation of epinephrine to adenochrome. Several approaches have been developed since then to improve sensitivity with the use of submicromolar probe concentration thus allowing minimal interferences of the probe on the biological process being investigated. Specificity has also been improved to increase the reaction rate of probes to certain RS through synthesis of new and innovative analogues that exploit the unique chemistry between the probe and RS. Chromophore stability was also achieved through improved molecular design, optimized experimental conditions, or addition of supramolecular reagents since chromophores impart inherent thermodynamic stability as a function of its chemical structure, solvent polarity, pH, temperature, or due to presence of oxido-reductants or other reactive substances. Improved sample preparation and high-throughput analysis were also developed in order to maximize efficiency in the measurement markers of oxidative stress and determination of antioxidant capacity (AOC) of known molecules, food, biological fluid, or tissue. Therefore, spectrophotometric techniques for RS measurement have found broad application in the fields of biomedical research, clinical chemistry, plant biology, food chemistry, environmental chemistry, radiation chemistry, pharmaceuticals, toxicology, or material science to name a few, or just simply for the investigation of RS production in simple chemical systems. However, unlike the fluorescence probes, spectrophotometric as well as most applications of chemiluminescence probes do not provide spectrospatial image of the RS localization in cells, hence, one cannot deduce the site of radical production unless multiple probes and/or inhibitors are used with varying compartmentalization property (i.e., extracellular or intracellular). For example, in the investigation of radical production in cellular NADPH oxidase, several methods had been suggested such as measurement of O2 consumption, use of SOD-ferricytochrome c and horseradish peroxidase (HRP)/inhibitable probe such as Amplex Red for extracellular O2 and H2O2, respectively, and the HPLC analysis of the 2-OH-E marker for the quantification of intracellular O2.
关键词： Clinical Chemistry,Oxidative Stress,Spectrophotometric Techniques,Environmental Chemistry,Reactive Species,Antioxidant Capacity,Biomedical Research,Chemiluminescence,Superoxide Dismutase,UV-Vis Absorption
更新于2025-09-04 15:30:14
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A brief review on mass/optical spectrometry for imaging analysis of biological samples
摘要： Imaging analysis, especially bioimaging analysis, has been a hot research topic in recent years. There are numerous imaging analysis techniques for diverse applications of a wide spectrum of samples, with their unique advantages and disadvantages, and there are several related reviews published yearly. Among them, imaging mass spectrometry (IMS) technique for studying the distribution of molecular or ionic species at the level of tissue, cell, or subcellular, with its main feature of combining mass spectra for molecular identification and image visualization for quick and convenient analysis. The IMS does not require chemical labeling or complex sample preparation. This review, mainly focuses on the popular emerging IMS technique, including related ionization techniques in connection with their IMS applications, and some unique optical imaging techniques such as chemiluminescence imaging and dual-modal bioimaging for biological sample analysis, with 105 related recent references.
关键词： laser,multimodal bioimaging,biomedical imaging,chemiluminescence,optical spectrometry,bioimaging analysis,dual-modal bioimaging,mass spectrometry,Imaging analysis,ionization source
更新于2025-09-04 15:30:14
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Graphene-Oxide and Hydrogel Coated FBG-Based pH Sensor for Biomedical Applications
摘要： A hydrogel coated fibre grating-based pH sensor for biomedical applications has been realised, where Graphene Oxide (GO) had been used to enhance the bonding between the coating and the fibre. Two methods of deposition of GO were analysed i.e., evaporation and co-electroplating. The paper concludes that the system of GO evaporated on the fibre + the hydrogel has a sensitivity much higher, (6.1 ± 0.5) pm/pH, than the system of Cu and GO co-electroplated + the hydrogel, (1.9 ± 0.1) pm/pH, for a pH range between 2 to 10. The other conclusion is that the first system has a less coating bonding energy with the optical fibre whereas the second system has a stronger bonding energy, with better durability.
关键词： FBG,surface functionalisation,pH,sensing,fibre optic,biomedical application,roughness,graphene oxide,wettability,GO
更新于2025-09-04 15:30:14
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Multifunctional piezoelectric elastomer composites for smart biomedical or wearable electronics
摘要： The development of nanogenerators that is capable of converting mechanical energy into electricity could enable extraordinary advances in biomedical devices and wearable consumer electronics. Piezoelectric composites have no intricate assemblies, providing a compact and reliable alternative to energy interconversion in biomedical electronics. This work deals with the development of a new class of piezoelectric elastomer composite which is integrated multiple potential functionalities. To fully understand and exploit the unique properties of the composited material, characterisations in terms of general mechanical, dynamic mechanical, and dynamic piezoelectric experimental investigations have been conducted. Three prototypes with individual application have been successfully built up utilising the piezoelectric elastomer composite. The versatility of the composite developed in this work presents its outstanding potential in building self-powered systems or biomedical implanted sensors.
关键词： Biomedical sensor,Piezoelectricity,Elastomer composite,Smart artery replacement
更新于2025-09-04 15:30:14
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[Institution of Engineering and Technology 12th European Conference on Antennas and Propagation (EuCAP 2018) - London, UK (9-13 April 2018)] 12th European Conference on Antennas and Propagation (EuCAP 2018) - A Liquid with Tuneable Dielectric Properties for Wideband Microwave Sensing of Biological Targets
摘要： Biomedical microwave systems require antenna-to-body matching to transfer electromagnetic energy efficiently through the skin and inside the body. In this paper a paraffin oil and saline water based matching liquid is presented that can be modified in a straight-forward manner to match various dielectrics. The permittivity of this liquid may be varied between 10-52 by altering the proportions of paraffin oil to water. The conductivity can be varied between 0.3 and 1.0S/m (at 3GHz) by altering the salinity of the water, without significantly altering the permittivity. Dielectric measurements and one- and two-pole Debye parameters are given for a range of different mixtures at frequencies of 0.5-10GHz. The results highlight the flexibility of the matching liquid and mark it as a suitable antenna coupling medium as well as a biological phantom material in the low GHz range.
关键词： Biomedical signal processing,Dispersive media,Microwave imaging
更新于2025-09-04 15:30:14
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[IEEE 2018 2nd International Symposium on Multidisciplinary Studies and Innovative Technologies (ISMSIT) - Ankara, Turkey (2018.10.19-2018.10.21)] 2018 2nd International Symposium on Multidisciplinary Studies and Innovative Technologies (ISMSIT) - An Efficient Retinal Blood Vessel Segmentation using Morphological Operations
摘要： The structure of retinal vessel carries information about many diseases. It is difficult to analyze this complex structure by human eye. Additionally, it has time-consuming process. In this study, an extremely lower complex and more successful retinal blood vessel segmentation method is proposed via using morphological operators. Colorful retinal images are divided into red, green and blue channels. Green channel is preferred for segmentation on the account of including clear details about retinal vessels. Then, adaptive threshold with 5x5 Gaussian window is applied in order to obtain clean vessel geometry. In the next step, retinal image is sharpened and then, 3x3 wiener filter is applied to it. After wiener filter, some noise in the image decreases but retinal image pixels soften. Therefore, Otsu thresholding is applied to softened images. Finally, morphological operation is performed on gray level images. The proposed method is implemented on test images in DRIVE database. The process time of our method is 0.7-0.8 second and it is faster than other methods. 95,61% accuracy, 85.096% sensitivity and 96.33% specificity rates are obtained.
关键词： image texture analysis,Biomedical image processing,image denoising,segmentation,image edge detection
更新于2025-09-04 15:30:14
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[IEEE 2018 IEEE 7th Global Conference on Consumer Electronics (GCCE) - Nara, Japan (2018.10.9-2018.10.12)] 2018 IEEE 7th Global Conference on Consumer Electronics (GCCE) - Shape-aware Medical Image Enhancement by Weighted Total Variation
摘要： In this paper, we propose a sharpening method for medical images combining weights on each pixel and Total Variation regularization. When weighting properly on each pixel in Total Variation regularization, information loss in optimization can be prevented. In the proposed method, weighting for each pixel is calculated from emphasis processing on an image and edge information, and Total Variation regularization is performed using weight information. As a result, noise removal and sharpening can be performed at the same time. Moreover, by comparing the proposed method with the conventional method, qualitative evaluation is carried out, and the effectiveness is shown.
关键词： Image enhancement,Image denoising,Medical diagnostic imaging,Biomedical imaging
更新于2025-09-04 15:30:14
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[IEEE 2018 IEEE 13th Annual International Conference on Nano/Micro Engineered and Molecular Systems (NEMS) - Singapore, Singapore (2018.4.22-2018.4.26)] 2018 IEEE 13th Annual International Conference on Nano/Micro Engineered and Molecular Systems (NEMS) - A Novel Method for Fabricating Graphene Sensors in Channel for Biomedical Applications
摘要： Graphene is a 2D material possessing extraordinary electrical, mechanical and optical properties which paves way for fabricate biomedical applications. A well-known method graphene-based devices is depositing graphene using chemical vapor deposition and transferring it to any substrate using polymer support like PDMS (Polydimethylsiloxane). In this process multiple wetting and drying steps are required which compromises the quality of graphene. Also, PMMA leaves residues that are difficult to remove. Here, we report a novel method to fabricate graphene sensors inside PDMS channels. In this method graphene/copper stack is bonded on a PDMS surface using mechanical pressure and temperature. This PDMS layer is then bonded to another PDMS substrate containing microchannel. Etchant is flown through the microchannel to etch the copper and obtain graphene on PDMS. The graphene obtained on PDMS is characterized using optical images, scanning electron microscopy and Raman spectroscopy. This is an easy, simple to use and scalable method to obtain graphene sensors inside microchannels for biomedical applications.
关键词： Chemical Vapor Deposition,Biomedical Applications,Microchannel,Graphene,PDMS
更新于2025-09-04 15:30:14
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Deep Learning in Image Cytometry: A Review
摘要： Artificial intelligence, deep convolutional neural networks, and deep learning are all niche terms that are increasingly appearing in scientific presentations as well as in the general media. In this review, we focus on deep learning and how it is applied to microscopy image data of cells and tissue samples. Starting with an analogy to neuroscience, we aim to give the reader an overview of the key concepts of neural networks, and an understanding of how deep learning differs from more classical approaches for extracting information from image data. We aim to increase the understanding of these methods, while highlighting considerations regarding input data requirements, computational resources, challenges, and limitations. We do not provide a full manual for applying these methods to your own data, but rather review previously published articles on deep learning in image cytometry, and guide the readers toward further reading on specific networks and methods, including new methods not yet applied to cytometry data.
关键词： image cytometry,machine learning,biomedical image analysis,convolutional neural networks,deep learning,cell analysis,microscopy
更新于2025-09-04 15:30:14