ABSTRACT
Accurate characterization of biological matter, for example, in tissue, cells, and biological fluids, is of high importance. For example, early and correct detection of abnormalities, such as cancer, is essential as it enables early and effective type-specific treatment, which is crucial for mortality reduction [1]. Moreover, it is imperative to investigate the effectiveness and toxicity of pharmaceutical treatments before administration in clinical practice [2]. However, biological matter characterization still faces many challenges. State-of-the-art imaging and characterization methods have drawbacks, such as the requirement to attach difficult-to-find and costly labels to the biological target (e.g., COVID-19 rapid tests), expensive equipment (e.g., magnetic resonance imaging), low accuracy (e.g., ultrasound), use of ionizing radiation (e.g., X-rays), and invasiveness [3]. The characterization of biological matter using microwave (μW), millimeter-wave (mmW), and terahertz (THz) spectroscopy is a promising alternative: it is label-free, does not require ionizing radiation, and can be noninvasive. Moreover, there is a significant difference in how different biological materials absorb, reflect, and transmit electromagnetic (EM) waves [4] that is due to the difference in their dielectric properties. The dielectric properties are described by the frequency-dependent material parameter called the complex permittivity f, which expresses how the material responds to an external oscillating electric field. The complex permittivity of a material determines how the material absorbs, reflects, and transmits EM waves at different frequencies (Figure 1). Since each biological material's permittivity spectrum is different, it acts as an EM fingerprint. A material's complex permittivity can be calculated from the reflection and transmission of EM waves through the material, described by the S-parameters, which can be measured using a vector network analyzer (VNA) transmitting and receiving EM waves over a range of frequencies. The amplitude and phase of the transmitted and reflected EM waves at different frequencies are influenced by different underlying biological effects at different scales. That causes the entire spectrum to provide information from the supracellular to the molecular and even atomic scale. © 2000-2012 IEEE.
ABSTRACT
In recent years monetary narrowing impact more on Turkey and developing countries. Therefore, the importance of industrial policy and technology management in developing countries has widely increased. Production and design strategies have to be planned carefully. Thus, evidently monetary narrowing and undesired exchange rate fluctuation affected investment and the cash flow in numerous sectors such as finances, funding, industry, service industry, agribusiness, livestock, building trade, research, and development, etc. In this context, this situation broadly hit the research, prototyping, manufacturing, and testing phase of the microstrip patch antennas. Today, patch antennas have widely utilized in telecommunication systems. Hence, this growth has increased interest in studies. As it is in every project, cost and efficiency are an essential part of the project design. Therefore, the ratio of cost is more important for Turkey and developing countries due to undesired exchange rate fluctuation, tax, financial obligations, and unexpected world events (e.g. COVID-19 pandemic). Commonly, the microstrip patch antenna comprises particular parts such as a radiating patch on top of the double-sided laminate and ground plane and feeding point located below the double-sided laminate. Therefore, microstrip patch antenna components play a significant role in patch antenna radiation characteristics. Moreover, specifications of the double-sided laminate, such as relative permittivity (or dielectric constant) and real physical thickness are essential elements of the patch antenna's radiation characteristics. Generally, high-quality dielectric substrates are developed and manufactured by western originated companies. Thus, the dielectric substrate with high-grade characteristics is hard to find for Turkey and developing countries. Importing is the only option and quite costly. Choosing a domestic dielectric substrate is inevitable, however insufficient for many cases. In this study, difficulties in microstrip patch antenna production and prototyping in Turkey are analyzed.
ABSTRACT
In this work, we present a UHF-RFID-based noninvasive sensor to measure the concentration of ethanol in water using the volume fraction of liquids in mixture solutions. The sensing system operates at the UHF band (860-928 MHz). The concentration of ethanol in water affects the dielectric properties of the solution and therefore the antenna sensitivity of the RFID tag. This sensor operates by measuring the change in permittivity of a solution because of the change in concentration of ethanol in water. We propose a flexible RFID-Tag sensor a low-cost alternative to identify the possible sensitivity of tag changes and is able to detect a variation of 25% in ethanol in 9 ml of deionized water (DI-Water). The solution is useful in avoiding counterfeit ethanol solutions that may be toxic. The experimental setup is inexpensive, portable, quick, and contactless. We present results for ethanol solutions ranging from 25% to 100% in a small tube container. © 2022 IEEE.
ABSTRACT
An X-band, free-space microwave sensor consisting of 30 radial spokes connected in a central hub with a gap region was designed, fabricated and tested. The sensor structure results in an electric dipole at 10 GHz with a split circular disc capacitor at the center. Viruses, dust, and soot particles in the gap region change the sensor’s impedance and its reflection coefficient monitored by a horn antenna and a network analyzer. The sensor sensitivity was 85.02 MHz/microliter for deionized water, 89.5 MHz/microliter for uninfected saliva, and 94.6 MHz/microliter for SARS-COV-2 infected saliva with 103 viruses/μL. Its sensitivity to a dielectric sample (ερ~5.84) was 3.23 MHz/mm3, and for iron particles was 16.25 MHz/mm3. All these samples were smaller than λ/30 at 10 GHz and could not be detected on uniform dielectric or metallic substrates without the spoke structure. A 2x2 array of spoke sensors was also constructed and tested as a feasibility study for designing larger metamaterial (MTM) periodic arrays. IEEE
ABSTRACT
The high-density microneedle array patch (HD-MAP) is a promising alternative vaccine delivery system device with broad application in disease, including SARS-CoV-2. Skin reactivity to HD-MAP applications has been extensively studied in young individuals, but not in the >65 years population, a risk group often requiring higher dose vaccines to produce protective immune responses. The primary aims of the present study were to characterise local inflammatory responses and barrier recovery to HD-MAPs in elderly skin. In twelve volunteers aged 69-84 years, HD-MAPs were applied to the forearm and deltoid regions. Measurements of transepidermal water loss (TEWL), dielectric permittivity and erythema were performed before and after HD-MAP application at t = 10 min, 30 min, 48 h, and 7 days. At all sites, TEWL (barrier damage), dielectric permittivity (superficial water);, and erythema measurements rapidly increased after HD-MAP application. After 7 days, the mean measures had recovered toward pre-application values. The fact that the degree and chronology of skin reactivity and recovery after HD-MAP was similar in elderly skin to that previously reported in younger adults suggests that the reactivity basis for physical immune enhancement observed in younger adults will also be achievable in the older population.
ABSTRACT
The analysis of dielectric properties in Novel Coronavirus (COVID-19) has become an important research branch since the outbreak of the epidemic in 2019. In order to detect the dielectric properties of microfluidics like virus with higher sensitivity, a radio frequency sensor model is proposed in this paper. First, based on the excellent characteristics of the microstrip meander-line such as more concentrated electric field distribution, the microstrip meander-line is introduced into the design of traditional cancellation sensor, which is called the meander sensor. Then, the relationship between transmission coefficients of the system and dielectric properties of microfluidics is given in this paper. The simulation results verify the ultra-sensitivity of the meander sensor. Even though the relative permittivity of microfluidics is changed in the order of magnitude 10-2, the measurement results of the meander sensor also change significantly. However, the straight sensor can only measure changes of relative permittivity in the order of magnitude 10-1. What's more, there is a more concentrated measurement range for the meander sensor. This will be more practical for measuring weak changes of dielectric properties caused by the microfluidics itself and its interactions. © 2021 IEEE.
ABSTRACT
Biological, physical and chemical interaction between one (or more) microorganisms and a host organism, causing host cell damage, represents an infection. Infection of a plant, animal or microorganism with a virus can prevent infection with another virus. This phenomenon is known as viral interference. Viral interference is shown to result from two types of interactions, one taking place at the cell surface and the other intracellularly. Various viruses use different receptors to enter the same host cell, but various strains of one virus use the same receptor. The rate of virus-receptor binding can vary between different viruses attacking the same host, allowing interference or coinfection. The outcome of the virus-virus-host competition is determined by the Gibbs energies of binding and growth of the competing viruses and host. The virus with a more negative Gibbs energy of binding to the host cell receptor will enter the host first, while the virus characterized by a more negative Gibbs energy of growth will overtake the host metabolic machine and dominate. Once in the host cell, the multiplication machinery is shared by the competing viruses. Their potential to utilize it depends on the Gibbs energy of growth. Thus, the virus with a more negative Gibbs energy of growth will dominate. Therefore, the outcome can be interference or coinfection, depending on both the attachment kinetics (susceptibility) and the intracellular multiplication machinery (permittivity). The ratios of the Gibbs energies of binding and growth of the competing viruses determine the outcome of the competition. Based on this, a predictive model of virus-virus competition is proposed.