Provides society information that may include news, reviews or technical notes that should be of interest to practitioners and researchers.

Provides society information that may include news, reviews or technical notes that should be of interest to practitioners and researchers.

This work presents a noninvasive imaging method to locate veins using a tuned microwave loop resonator. It offers a low-cost, fast, and effective solution to the challenges in venipuncture. The sensor features a loop resonator with a 5.2 mm radius, incorporating a self-tuning mechanism, and operates at 2.408 GHz with a reflection coefficient of -48.77 dB. It generates localized high-intensity electric fields that penetrate tissues to sufficient depths, enabling the detection of veins based on shifts in resonant frequencies that are induced by the varied dielectric properties of blood vessels. Two-dimensional raster scan simulations of the cephalic and median cubital veins yielded a similar to 25 MHz downward resonant-frequency shift between vein and non-vein positions, with the median cubital vein still detectable at depths up to 6 mm. To quantify generalization to real tissues, a decision tree classifier trained on 63 simulation samples and evaluated on 335 in vivo measurements achieved 82.09% classification accuracy (sensitivity 81.25%, specificity 83.02%), demonstrating that the simulation-derived frequency contrast transfers reliably to experimental data despite inter-subject tissue variability. Extensive tests conducted demonstrate the sensor's effectiveness, producing consistent and distinguishable frequency shifts when the sensor moves on the skin across veins. This technology holds significant promise for improving venipuncture accuracy, minimizing complications, and enhancing patient comfort.

Provides society information that may include news, reviews or technical notes that should be of interest to practitioners and researchers.

Provides society information that may include news, reviews or technical notes that should be of interest to practitioners and researchers.

This work introduces a refined image-processing method explicitly designed to amalgamate raster-scanned images obtained with a compact planar microwave resonator. The resonator tuned for use on the skin provides a deeper field penetration into the dermis layer, compared to the skin impedance measurements. The resonance of the sensor is sensitive to the dielectric properties of the tissues underneath the skin. Healthy and abnormal tissues exhibit different dielectric characteristics. Pixelated images can leverage resonant frequencies and reflection coefficients to enhance contrasts and boundaries to identify the abnormal tissues. We proposed using analytical tools like the structural similarity index to correlate frequency shifts with reflection coefficient magnitudes precisely. Preliminary results suggested the adeptness of the technique at classifying whether the tissue depth surpasses 15 mm and detecting tumor locations with a high accuracy when the image depth does not exceed 15 mm. A compact neural network model was implemented for processing the microwave images when the tumor depth exceeded 15 mm and achieved a high Dice coefficient. The work incorporated simulations to substantiate the novel concept and demonstrated its potential for noninvasive, efficient, and cost-effective subcutaneous imaging in medical applications.

Provides society information that may include news, reviews or technical notes that should be of interest to practitioners and researchers.

In this work, a planar radio-frequency sensor is developed for noninvasive and efficient monitoring of water content variations in human body and tissues. The sensor operates on the principle of electromagnetic resonance, which is highly sensitive to changes in dielectric properties influenced by water content. Designed on a FR4 substrate, the planar loop resonator, tuned with an embedded metal pad, features enhanced resonance performance, compactness, sensitivity and wearability. Experiments conducted to monitor hydration processes on the forearm of a human subject at different days demonstrate the sensor ability to detect distinct trends as an individual's transition from dehydrated to hydrated states. The sensor's small, planar form factor offers promising potential for integration into a wearable device to be worn on the human forearm, enabling continuous and reliable hydration monitoring.

In this article, the significance, clinical needs, methods and principles for continuous human body hydration level monitoring are reviewed. Maintaining hydrated is critical for physical and mental health. A long-term, continuous, convenient and accurate wearable device that can monitor the whole-body water content to provide real-time feedback is needed, especially for infants, the elderly, and people who have special needs in their tasks and occupations. Noninvasive bioimpedance measurements and microwave sensing techniques suitable for conformable wearables are summarized. Microwave probing with deeper field penetrations into the dermis layer of the skin can provide a better assessment of whole-body water content. Frequency choices for the probing signals, the need for realistic phantoms, and evaluation standards suitable for clinical uses are discussed.

The Inter-Society Technology Panel (ISTP) program was established in 2021 by the IEEE Microwave Theory and Technology Society (MTT-S) as a new initiative under the auspices of the MTT-S Inter-Society Committee. This program, currently led by Drs. Ke Wu and J.-C. Chiao, collaborated with the 2023 European Microwave Week (EuMW) Steering Committee and ISTP organizers to develop two exciting panels for EuMW 2023 in Berlin, Germany. The ISTP program’s goal is to provide an international platform for collaboration and exchanges of ideas among members of MTT-S, other IEEE entities (societies and councils), and non-IEEE organizations. These panels aim to facilitate discussions on cross-disciplinary research and development, involving academia, industry, standards, and commercial sectors in the context of emerging technologies and applications.

Electrodeposited iridium oxide (IrOx) pH sensors are gaining interest in numerous biomedical applications, attributed to their superior accuracy, straightforward fabrication, and compatibility with other microfabrication processes. However, the pH sensing range and stability of these sensors have been long-entrenched challenges to control. In this study, we explored the sensor’s behavior under pH conditions beyond its typical sensing range, unearthing potential correlations between the sensing range and other influential factors. Based on these findings, we proposed and implemented a practical method to manipulate the sensing range to designated pH regions. This methodology significantly expanded the sensor’s applicability to encompass extreme acidic or basic environments. A series of investigations revealed that, under such severe conditions, the sensor’s stability - as quantified by drift - could be enhanced more than tenfold post-treatment. Moreover, other stability metrics, including linearity and hysteresis, exhibited notable improvements through this technique, as validated by titration tests in the extended pH sensing ranges. This research offers meaningful insights and a promising approach to enhance the sensing range and stability of electrodeposited IrOx pH sensors, thereby potentially progressing their practical application in biomedical domains.

In this letter, a wireless portable electrochemical measurement system is designed for the detection of VP28, a critical protein linked to the white spot syndrome virus (WSSV), which causes significant negative impacts on the shrimp farming industry worldwide. The system includes a screen-printed electrochemical immunosensor, an integrated measurement circuit, and a user interface compatible with Windows computers and Android devices. By employing cyclic voltammetry on a gold sensor functionalized with VP28-specific antibodies, the system exhibits a strong linear correlation between percentage variation in peak current and VP28 concentrations ranging from 5 to 25 ng/mL with a coefficient R-2 of 0.994. This system provides a practical solution for onsite detection of VP28 in shrimp farming, with an impressive detection limit of 2.38 ng/mL. It allows for real-time data display on computers or smartphones through both wired and wireless connections, facilitating prompt management of WSSV outbreaks.

Provides society information that may include news, reviews or technical notes that should be of interest to practitioners and researchers.

This work aims to develop a planar microwave sensor fabricated on a flexible polyimide substrate to monitor the water content of fruits nondestructively. The sensor is based on a planar loop resonator tuned with a concentric metal pad that features improved resonance, compact size, and flexibility to conform to the curved surface of the fruit. The sensing mechanism is to detect electromagnetic resonance that is susceptible to dielectric property changes by water content variations. The robust resonance provides electric fields that penetrate deeper into the fruit tissues, compared to an untuned one, with a sufficient spectral resolution to reach high sensitivity. Experiments were conducted, including long-term continuous water content monitoring and total water content measurements. The sensors demonstrated clear frequency shifting trends when fresh apples became dehydrated, and their initial resonant frequencies indicated total water contents. Simulations were conducted to examine measurement discrepancies induced by inhomogeneous water evaporation and surface curvatures. The feasibility of sensing the watercore defects inside apples was demonstrated with simulations. Additionally, the sensor was used to demonstrate the feasibility of measuring water content in potatoes. The promising results show the great potential of the noninvasive and continuous water-content sensor applications in agriculture to study the growth, maturity, anomaly, and storage of fruits and in food processing applications to achieve optimal quality.

The pH value in bodily fluids is a crucial diagnostic marker. Conventional glass-rod pH sensors display reliability in aqueous solutions, but the pH-sensitive glass membrane makes them prone to inaccuracies in viscous solutions due to elevated junction potentials and bulky design hinders miniaturization. To overcome this issue, this work introduces a new pH sensor design and fabrication that enables miniaturization and reliability in aqueous and viscous solutions and facilitates insertion into a needle for in vivo monitoring. Utilizing a printing technique for the application of iridium oxide (IrOx) and silver/silver chloride coating on a single flexible polyimide substrate offers cost-effectiveness and production scalability. The sensor then is tailored with a sharp blade to a narrow strip that fits into a 20-gauge needle. The electrochemical measurements demonstrate that electrodes produced through this method demonstrate an accuracy of up to 0.1 pH within a narrow pH range (7.35-7.45) in buffer solutions and real human serum tests.

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