Contactless and Wireless Wound Monitoring Using Nitrogen-Doped Graphene Antenna Sensor.

Hypothyroidism affects corneal homeostasis and wound healing in mice

Topically applied opioids promote angiogenesis and healing of ischemic wounds in rats. We examined if topical fentanyl stimulates wound healing in diabetic rats by stimulating growth-promoting signaling, angiogenesis, lymphangiogenesis and nerve regeneration. We used Zucker diabetic fatty rats that develop obesity and diabetes on a high fat diet due to a mutation in the Leptin receptor. Fentanyl blended with hydrocream was applied topically on ischemic wounds twice daily, and wound closure was analyzed regularly. Wound histology was analyzed by hematoxylin and eosin staining. Angiogenesis, lymphangiogenesis, nerve fibers and phospho-platelet derived growth factor receptor-β (PDGFR-β) were visualized by CD31-, lymphatic vessel endothelium-1, protein gene product 9.5- and anti-phospho PDGFR-β-immunoreactivity, respectively. Nitric oxide synthase (NOS) and PDGFR-β signaling were analyzed using Western immunoblotting. Fentanyl significantly promoted wound closure as compared to phosphate-buffered saline (PBS). Histology scores were significantly higher in fentanyl-treated wounds, indicative of increased granulation tissue formation, reduced edema and inflammation, and increased matrix deposition. Fentanyl treatment resulted in increased wound angiogenesis, lymphatic vasculature, nerve fibers, nitric oxide, NOS and PDGFR-β signaling as compared to PBS. Phospho-PDGFR-β co-localized with CD31 co-staining for vasculature. Topically applied fentanyl promotes closure of ischemic wounds in diabetic rats. Increased angiogenesis, lymphangiogenesis, peripheral nerve regeneration, NO and PDGFR-β signaling are associated with fentanyl-induced tissue remodeling and wound healing.

Recently, we discovered that the resonant frequency of a microstrip patch antenna is sensitive to mechanical strains or crack presence in the ground plane. Based on this principle, antenna sensors have been demonstrated to measure strain and detect crack in metallic structures. This paper presents a wireless method to remotely interrogate a dual-frequency antenna sensor. An interrogation horn antenna was used to irradiate the antenna sensor with a linear chirp microwave signal. By implementing a light-activated switch at the sensor node and performing signal processing of the backscattered signals, the resonant frequencies of the antenna sensor along both polarizations can be measured remotely. Since the antenna sensor does not need a local power source and can be interrogated wirelessly, electric wiring can be eliminated. The sensor implementation, the signal processing and the experimental setup that validate the remote interrogation of the antenna sensor are presented. A power budget model has also been established to estimate the maximum interrogation range.

The diagnostics of cracks in structures has been gaining importance in recent years. In the past decade, numerous sensors were developed to detect and monitor the crack propagation, but very few sensors can extract quantified information about the crack such as its size and orientation. Recently, we have presented a passive wireless antenna sensor that can detect sub-millimeter crack growth when the crack is parallel to one edge of the antenna patch. This paper studies the capability of the antenna sensor to detect crack orientation. Based on the principle of microstrip patch antenna, an antenna sensor with a rectangular patch radiates at two resonant frequencies. Cracks in the ground plane of the sensor with different orientations influence these two resonant frequencies in two different ways. Thus by monitoring the changes in both resonant frequencies of the antenna sensor, quantitative information about the crack orientations can be obtained. The resonant frequencies of the antenna sensor were first simulated using an EM simulation tool by modeling the crack as a 0.7 mm wide slot oriented at various angles. Simulation results confirmed that the resonant frequencies of the antenna sensor are sensitive to the crack orientation. Subsequently, the antenna sensor's capability to detect crack orientation was experimentally validated by fabricating an antenna sensor on a double-clad circuit board. A mini-milling machine was employed to produce cracks in the ground plane at different angles. The resonant frequencies of the antenna sensor were then measured at different crack lengths to study the effect of crack orientation and length on both frequencies of the antenna sensor. The principle of operation will be discussed first, followed by detailed descriptions on the simulation model, sensor design and fabrication, experimental setup and procedure, results and analysis.

In this paper, a flexible microstrip patch antenna sensor is proposed for monitoring of the moisture content of lubricating oil. The sensor identifies liquids having different effective dielectric constants by detecting changes in the resonance frequency. The proposed antenna comprises a radiation patch, a metal ground plane, and a PDMS substrate with microchannels. The microchannels are etched on the PDMS substrate. When the relative permittivity of the microfluidic channel is 1.8∼12.5, the operating frequency of the proposed antenna changes from 2.230 to 2.116 GHz, and the amplitude of the reflection coefficient is greater than −26.3 dB. The simulation and measurement results show that the proposed sensor can monitor the lubricating oil with different moisture contents, which can cause frequency separation of at least 20 MHz and achieve a good linear response. Therefore, the proposed sensor has the feasibility of monitoring the quality of lubricating oil.

This paper presents the development of a flexible antenna made of Polydimethylsiloxane (PDMS) and Copper (Cu) patch. The antenna comprises of Cu tape as the patch and ground plane, PDMS composite as the substrate and SMA connector as the coaxial feed with dimensions of 21.5mm patch radius, 60×60×3 mm3 substrate area and 60×60 mm2 ground plane area. In this study, we also create a PDMS+glass microsphere composite as substitute to the PDMS substrate. The PDMS+glass inclusion reduces PDMS's relative permittivity and loss tangent to 1.9 and 0.014 respectively which could enhance antenna's performance. To overcome adhesiveness issue between Cu patch and PDMS substrate, the antenna was encapsulated with another thin layer of PDMS/PDMS+glass substrate of 0.6mm thickness to ensure a constant distance from the ground plane. CST software was used to simulate antenna resonance frequency prior to the fabrication. Measurements using a Vector Network Analyzer (VNA) showed that the PDMS substrate antennas resonated at 1.92 GHz (without encapsulation) and 2.34 GHz (with encapsulation) while the PDMS+glass substrate antennas resonated at 2.46 GHz (without encapsulation) and 2.25 GHz (with encapsulation) respectively. Here, we also discussed the effect of substrate on return loss. Overall, results obtained from the measurements are in agreement with the simulation results.

Non-Invasive antenna sensor based continuous glucose monitoring using pancreas dielectric radiation signal energy levels and machine learning algorithms

In this study a new built-in ultrahigh frequency (UHF) antenna sensor was designed and applied in a high-voltage switchgear for partial discharge (PD) detection. The casing of the switchgear was initially used as the ground plane of the antenna sensor, which integrated the sensor into the high-voltage switchgear. The Koch snowflake patch was adopted as the radiation patch of the antenna to overcome the disadvantages of common microstrip antennas, and the feed position and the dielectric layer thickness were simulated in detail. Simulation results show that the antenna sensor possessed four resonant points with good impedance matching from 300 MHz to 1000 MHz, and it also presented good multi-frequency performance in the entire working frequency band. PD detection experiments were conducted in the high-voltage switchgear, and the fabricated antenna sensor was effectively built into the high-voltage switchgear. In order to reflect the advantages of the built-in antenna sensor, another external UHF antenna sensor was used as a comparison to simultaneously detect PD. Experimental results demonstrated that the built-in antenna sensor possessed high detection sensitivity and strong anti-interference capacity, which ensured the practicability of the design. In addition, it had more high-voltage switchgear PD detection advantages than the external sensor.

This paper presents a flexible low-profile antenna sensor for fatigue crack detection and monitoring. The sensor was inspired by the sense of pain in bio-systems as a protection mechanism. Because the antenna sensor does not need wiring for power supply or data transmission, it is an ideal candidate as sensing elements for the implementation of engineering sensor skins with a dense sensor distribution. Based on the principle of microstrip patch antenna, the antenna sensor is essentially an electromagnetic cavity that radiates at certain resonant frequencies. By implementing a metallic structure as the ground plane of the antenna sensor, crack development in the metallic structure due to fatigue loading can be detected from the resonant frequency shift of the antenna sensor. A monostatic microwave radar system was developed to interrogate the antenna sensor remotely. Fabrication and characterization of the antenna sensor for crack monitoring as well as the implementation of the remote interrogation system are presented.

Wound healing has evolved in recent years, resulting in diverse therapeutic options. This study evaluated the effects of the somatic antigen of the hydatid cyst protoscolex on wound healing in mice with full-thickness skin wounds. Fifty-four adult mice, weighing 25±5g and approximately 60 days old, were divided into three groups (A, B, and C), each further divided into three subgroups. Subgroups A1, A2, and A3 were assigned negative controls. B1, B2, and B3 received hydatid cyst somatic antigen tests at 10µg/SC, whereas C1, C2, and C3 received somatic antigen tests at 20µg/SC. Under general anesthesia, a wound biopsy puncture of 9.8mm in diameter was performed on the mice's back and spine. In the experimental group, antigen and alum adjuvant were administered subcutaneously around the wound, while the control group received Phosphate-Buffered Saline (PBS). Using digital images, a geometric assessment was conducted on days 0, 1, 3, 6, 9, 12, 15, 18, and 21 post-wounding. The obtained images were analyzed by Image J software and after analyzing the data by SPSS software. A significant difference in terms of epithelization was observed in the antigen treatment group with a dose of 20µg on days 3 and 6 (P<0.05). Furthermore, the 20µg antigen group was significantly higher than the 10µg antigen group in terms of this factor on day 3 (P<0.05). Skin samples were taken from all wounds on days 3, 10 and 21 for microscopic evaluation. Regarding epithelization, on day 10, a significant difference was observed in the treatment group with a concentration of 10µg with the control group and the treatment group with a concentration of 20µg (P<0.05). Based on the results of the present study, it can be concluded that somatic antigens of protoscolex hydatid cyst are dose-dependent and antigens with a dose of 20µg by subcutaneous injection accelerate wound healing and epithelialization.

A major goal of structural health monitoring (SHM) is crack detection and monitoring. Because cracks are localized defects, quantifying the sizes and locations of the cracks would require placing many sensors over a large area. We present a crack sensor that is suitable for densely distributed sensor network because they can be remotely interrogated and do not need any wiring for data transmission or power supply. A rectangular patch antenna, consisting of a metallic patch on one side of a dielectric substrate and a ground plane on the other side of the substrate, is studied in this paper for crack detection and monitoring. The presence of a crack in the ground plane of the antenna changes its conductivity, which in turn reduces the resonant frequency of the antenna sensor. Experimental results demonstrated that the antenna sensor can monitor crack growth with sub-millimeter spatial resolution. Detailed experimental set-up and measurement results are presented.

A microstrip patch antenna sensor was studied for shear sensing with a targeted application of measuring plantar shear distribution on a diabetic foot. The antenna shear sensor consists of three components, namely an antenna patch, a soft foam substrate and a slotted ground plane. The resonant frequency of the antenna sensor is sensitive to the overlapping length between the slot in the ground plane and the antenna patch. A shear force applied along the direction of the slot deforms the foam substrate and causes a change in the overlapping length, which can be detected from the antenna frequency shift. The antenna shear sensor was designed based on simulated antenna frequency response and validated by experiments. Experimental results indicated that the antenna sensor exhibits high sensitivity to shear deformation and responds to the applied shear loads with excellent linearity and repeatability.

A patch antenna, consisting of a radiation patch, a dielectric substrate, and a ground plane, resonates at distinct fundamental frequencies that depend on the substrate dielectric constant and the dimensions of the radiation patch. Since these parameters change with the applied strain and temperature, this study investigates simultaneous strain and temperature sensing using a single antenna that has two fundamental resonant frequencies. The theoretical relationship between the antenna resonant frequency shifts, the temperature, and the applied strain was first established to guide the selection of the dielectric substrate, based on which an antenna sensor with a rectangular radiation patch was designed and fabricated. A tensile test specimen instrumented with the antenna sensor was subjected to thermo-mechanical tests. Experiment results validated the theoretical predictions that the normalized antenna resonant frequency shifts are linearly proportional to the applied strain and temperature changes. An inverse method was developed to determine the strain and temperature changes from the normalized antenna resonant frequency shifts, yielding measurement uncertainty of 0.4 °C and 17.22 μ for temperature and strain measurement, respectively.

The use of flexible, built-in, ultra-high-frequency (UHF) antenna sensors is an effective method to solve the weak high-frequency electromagnetic wave signal sensing of partial discharge (PD) inside gas-insulated switchgears (GISs), and the compatibility of flexible UHF antenna sensor substrate materials and SF6/N2 mixtures is the key to the realization of a flexible UHF antenna sensor inside a GIS. Based on this, this paper builds an experimental platform for the compatibility of a 30% SF6/70% N2 gas mixture and a PD flexible UHF antenna sensor substrate and conducts compatibility experiments between the 30% SF6/70% N2 gas mixture and PD flexible UHF antenna sensor substrate under different temperatures in combination with the actual operating temperature range of the GIS. In this article, a Fourier transform infrared spectrometer, scanning electron microscope and X-ray photoelectron spectrometer were used to test and analyze the gas composition, the surface morphology and the elemental change in the PD flexible UHF antenna sensor substrate, respectively. PET material will be slightly oxidized under the environment of a 30% SF6/70% N2 gas mixture at 110 °C, PI material will generate metal fluoride under the environment of a 30% SF6/70% N2 gas mixture and only PDMS material will remain stable under the environment of a 30% SF6/70% N2 gas mixture; therefore, it is appropriate to use PDMS substrate in the development of flexible UHF antenna sensors.

This article presents the design of a wearable textile antenna sensor for knee effusion diagnosis application. According to human anatomy, effusion is the collection of synovial fluid in a specific anatomic space. Knee effusion, often known as water on the knee, is a condition in which excess fluid collects around the knee joint. The antenna sensing patch region is embroidered using an automated computerized embroidery machine, while the design parameters were optimized using machine learning (ML) algorithms, including deep neural network (DNN). For the best fit on a knee joint, an annular elliptical structure of electronic textile (E-textile) antenna sensor is developed. Pure silver-coated highly conductive thread with improved flexibility is used for embroidering the patchwork in order to enhance the feasibility of the proposed device. The fabricated antenna sensor has the operating resonance frequency at 2.19 GHz and performs diagnosis based on the concept of reflection coefficient parameter. Furthermore, the specific absorption rate (SAR) level of a proposed sensor device is being evaluated on the knee joint and has been kept below the safety limit value of 1.6 W/kg averaged over 1 g of tissue model.