Alzheimer disease biomarker based on carotid artery reactivity

Alzheimer disease (AD) is a progressive neurodegenerative disorder associated with the disruption of neuronal function. Carotid Artery Reactivity (CAR) is a new biomarker method for AD detection which provides various advantages as compared to existing detection method. Current developed methods have either radiation risk (positron emission tomography [PET] and computed tomography [CT] scanning), high cost and long scanning duration (magnetic resonance imaging [MRI]) or lack accuracy (electroencephalography [EEG]). New AD detection method could be implemented using ultrasound machine by assessing the carotid artery condition since the impairment of this artery leads to brain hypoperfusion, a clinical feature of AD. CAR allows normal functioning artery to dilate in order to permit more bloods flow into the brain. The three different variables utilized to study the CAR were the carotid artery blood flow velocity, its diameter and cross sectional area. Healthy people and Alzheimer patient are believed to have different CAR value. Hence, this study emphasized on finding the normal reactivity value belonging to healthy people and Alzheimer patient. This CAR value could be used to differentiate between healthy people and Alzheimer patient as the new method of detection. The studied subject consisted of 40 healthy people and 20 Alzheimer patients. All subjects had been scanned with ultrasound machine using Doppler and 3D technique before and after performed exercise to achieve 85% of their Maximal Heart Rate (MHR). Readings of each reactivity variables before exercise (rest) and after exercise (stimulated) were recorded to be analyzed to compare its percentage increment value (reactivity). Based on the results, Alzheimer patient recorded very low reactivity value which were 21% (blood flow velocity), 8.1% (diameter changes) and 16.67% (area changes) while normal reactivity recorded high reactivity value which were 109%(blood flow velocity), 22.2% (diameter changes) and 49.59% (area changes)

Hybrid graphene–copper UWB array sensor for brain tumor detection via scattering parameters in microwave detection system

Hybrid graphene–copper ultra-wideband array sensor applied to microwave imaging technique is successfully used in detecting and visualizing tumor inside human brain. The sensor made of graphene coated film for the patch while copper for both the transmission line and parasitic element. The hybrid sensor performance is better than fully copper sensor. Hybrid sensor recorded wider bandwidth of 2.0–10.1 GHz compared with fully copper sensor operated from 2.5 to 10.1 GHz. Higher gain of 3.8–8.5 dB is presented by hybrid sensor, while fully copper sensor stated lower gain ranging from 2.6 to 6.7 dB. Both sensors recorded excellent total efficiency averaged at 97 and 94%, respectively. The sensor used for both transmits equivalent signal and receives backscattering signal from stratified human head model in detecting tumor. Difference in the data of the scattering parameters recorded from the head model with presence and absence of tumor is used as the main data to be further processed in confocal microwave imaging algorithm in generating image. MATLAB software is utilized to analyze S-parameter signals obtained from measurement. Tumor presence is indicated by lower S-parameter values compared to higher values recorded by tumor absence

Bandwidth and gain enhancement of a circular microstrip antenna using a DNG split ring resonator radome

This paper present the design of a circular patch microstrip antenna with enhancement in terms of bandwidth and gain using a dielectric double negative (DNG) split ring metamaterial radome. This radome is positioned on top of the CP antenna operating from 5.2 GHz to 6.4 GHz. The metamaterial radome comprises of two alternate split rings of negative permittivity, permeability and refractive index. The circular microstrip antenna bandwidth of 430 MHz has been realized by the presence of DNG metamaterial radome compared to 220 MHz without the radome. The gain has been increased as well from 1.84 dBi to 3.87 dBi

Low insertion loss of surface mount device low pass filter at 700 MHz

The paper involved with the design, simulation and fabrication of 6th order elliptical-based Surface Mount Device (SMD) LPF with cutoff frequency at 700 MHz. Fabricated LPF is consisted of four PCB layers which components of SMD are soldered on the top layer. Another three layers is for grounding and shielding, power supply and grounding void. The four layers is crucial to avoid interference between components. The research has find out that the momentum simulation is definitely required to improve the signals response compared to a normal simulation by ADS software. The comparison between momentum simulated versus measured and normal simulated versus measured is 0.2 dB and 29 dB correspondingly. Such huge difference leads to conclusion that momentum simulation is saving time without having much struggles and efforts to get optimum readings. The Proposed SMD LPF has a very low insertion loss of 0.965dB with a transition region of 195 MHz which is good steepness to avoid any image frequency

Multiband slot-loaded dipole antenna for WLAN and LTE-A applications

A multiband printed dipole antenna for wireless local area network (WLAN) and long-term evolution-advanced (LTEA) applications is investigated here. Its multiband characteristic is enabled by the Y-slot present in the upper arm of the dipole, while the antenna\u27s dimensions are 0.08λo × 0.384λo at the lowest operating frequency. It features bandwidth of 14.6% centred at 2.4 GHz, and ∼30.5% centred at 5.5 GHz for WLAN operation. An additional bandwidth of 6.9% centred at 3.5 GHz supporting LTE-A applications is also featured. Besides being compact, the proposed antenna radiates omnidirectionally with a gain of up to 4.09 dBi. Simulations and measurements are in good agreement

Zero-index metamaterial superstrates uwb antenna for microwave imaging detection

Metamaterials (MTM) can enhance the properties of microwaves and also exceed some limitations of devices used in technical practice. Note that the antenna is the element for realizing a microwave imaging (MWI) system since it is where signal transmission and absorption occur. UltraWideband (UWB) antenna superstrates with MTM elements to ensure the signal transmitted from the antenna reaches the tumor and is absorbed by the same antenna. The lack of conventional head imaging techniques, for instance, Magnetic Resonance Imaging (MRI) and Computerized Tomography (CT)scan, has been demonstrated in the paper focusing on the point of failure of these techniques for prompt diagnosis and portable systems. Furthermore, the importance of MWI has been addressed elaborately to portray its effectiveness and aptness for a primary tumor diagnosis. Other than that, MTM element designs have been discussed thoroughly based on their performances towards the contributions to the better image resolution of MWI with detailed reason-ings. This paper proposes the novel design of a Zeroindex Split Ring Resonator (SRR) MTM element superstrate with a UWB antenna implemented in MWI systems for detecting tumor. The novel design of the MTM enables the realization of a high gain of a superstrate UWB antenna with the highest gain of 5.70 dB. Besides that, the MTM imitates the conduct of the zeroreflection phase on the resonance frequency, which does not exist. An antenna with an MTM unit is of a 7 × 4 and 10 × 5 Zero-index SRR MTM element that acts as a superstrate plane to the antenna. Apart from that, Rogers (RT5880) substrate material is employed to fabricate the designed MTM unit cell, with the following characteristics: 0.51 mm thickness, the loss tangent of 0.02, as well as the relative permittivity of 2.2, with Computer Simulation Technology (CST) performing the simulation and design. Both MTM unit cells of 7 × 4 and 10 × 5 attained 0° with respect to the reflection phase at the 2.70 GHz frequency band. The first design, MTM Antenna Design 1, consists of a 7 × 4 MTM unit cell that observed a rise of 5.70 dB with a return loss (S11) −20.007 dB at 2.70 GHz frequency. The second design, MTM Antenna Design 2, consists of 10 × 5 MTM unit cells that recorded a gain of 5.66 dB, having the return loss (S11) −19.734 dB at 2.70 GHz frequency. Comparing these two MTM elements superstrates with the antenna, one can notice that the 7 × 4 MTM element shape has a low number of the unit cell with high gain and is a better choice than the 10 × 5 MTM element in realizing MTM element superstrates antenna for MWI

Ganoderma boninense classification based on near-infrared spectral data using machine learning techniques

Ganoderma boninense (G. boninense) infection reduces the productivity of oil palms and causes a severe threat to the palm oil industry. Early detection of G. boninense is vital since there is no effective treatment to stop the continuing spread of the disease unless ergosterol, a biomarker of G. boninense can be detected. There is yet a non-destructive and in-situ technique explored to detect ergosterol. Capability of NIR to detect few biomarkers such as mycotoxin and zearalenone (ZEN) has been proven to pave the way an effort to explore NIR’s sensitivity towards detecting ergosterol, as discussed in this paper. A compact hand-held NIR with a measurement range of 900–1700 nm is utilized by scanning the leaves of three oil palm seedlings inoculated with G. boninense while the other three were non-inoculated from 16-weeks-old to 32-weeks-old. Significant changes of spectral reflectance have been notified occur at the wavelength of ~1450 nm which reflectance of infected sample is higher 0.2–0.4 than healthy sample which 0.1–0.19. The diminishing of the spectral curve at approximately 1450 nm is strongly suspected to happened due to the loss of water content from the leaves since G. boninense attacks the roots and causes the disruption of water supply to the other part of plant. However, a few overlapped NIRs’ spectral data between healthy and infected samples require for further validation which chemometric and machine learning (ML) classification technique are chosen. It is found the spectra of healthy samples are scattered on the negative sides of PC-1 while infected samples tend to be on a positive side with large loading coefficients marked significant discriminatory effect on healthy and infected samples at the wavelength of 1310 and 1452 nm. A PLS regression is used on NIR spectra to implement the prediction of ergosterol concentration which shows good corelation of R = 0.861 between the ergosterol concentration and oil palm NIR spectra. Four different ML algorithms are tested for prediction of G. boninense infection: K-Nearest Neighbour (kNN), Naïve Bayes (NB), Support Vector Machine (SVM) and Decision Tree (DT) are tested which depicted DT algorithm achieves a satisfactory overall performance with high accuracy up to 93.1% and F1-score of 92.6% compared to other algorithms. High accuracy shows the capability of the classification model to correctly predict the G. boninense detection while high F1-score indicates that the classification is able to validate the detection of G. boninense correctly with low misclassification rate. The result represents a significant step in the development of a nondestructive and in-situ detection system which validated by both chemometric and machine learning (ML) classification technique

Compact bidirectional circularly polarized dedicated short range communication antenna for on‐board unit vehicle‐to‐everything applications

This article presents a newly circularly polarized (CP) antenna for V2X's dedicated short range communications applications. Its CP characteristic is enabled by a 70 Ω sequential phase feeding network and sequential rotation technique designed on top of the substrate. It has features of ≈90° phase difference in sequence between ports of S 21 = 2.4°, S 31 = −87°, S 41 = −180°, and S 51 = −276°, resulting in a 2.19 dB axial ratio centered at 5.9 GHz. The length of the SP feeding network to each ports designed in the different form of meander lines are the key to control the generated phase at the center frequency It also contributes to the smaller final size of 0.59λ × 0.59λ . The proposed antenna operated from 5.850 to 5.925 GHz with a gain between 4 and 6 dBi. The gains are radiated in bidirectional mode due to the presence of the complimentary dipoles located on the opposite side of the substrate. These features indicate the suitability of the proposed antenna in compliance to the ITS‐G5 OBU V2X standard

Compact Broadband Triple-Ring Five-Port Reflectometer for Microwave Brain Imaging Applications

The broadband five-port refectometer (FPR) is proposed using a triple-ring based technique. The design introduces a tapering in the inter-ring transmission lines (TLs), which provides additional degrees of freedom for optimization and contributes to increased bandwidth. The miniaturization strategy allows incorporating the third ring without signifcant size increase. In addition, a method for expressing the effective physical dimension of a planar symmetric FPR is also presented in an easily comprehensible way, which can be implemented for other symmetric planar junctions with more than four ports. The proposed design comprises three concentric rings with phase-shifting arrangements between the inter-ring TLs and outer matching arm sections. Inter-ring TLs are shifted by 36 degrees(half factorized value of the inter-port angular distance of 72 degrees) in three different optimizing steps. Tapered TLs have been used between two consecutive rings to achieve very wide bandwidth of at least 88% in simulations and at least 85% in measurements

Multiband slot-loaded dipole antenna for wlan and lte-a applications

A multiband printed dipole antenna for wireless local area network (WLAN) and long-term evolution-advanced (LTE-A) applications is investigated here. Its multiband characteristic is enabled by the Y-slot present in the upper arm of the dipole, while the antenna's dimensions are (0.08λo × 0.384λo) at the lowest operating frequency. It features bandwidth of 14.6% centred at 2.4 GHz, and ~30.5% centred at 5.5 GHz for WLAN operation. An additional bandwidth of 6.9% centred at 3.5 GHz supporting LTE-A applications is also featured. Besides being compact, the proposed antenna radiates omnidirectionally with a gain of up to 4.09 dBi. Simulations and measurements are in good agreement