Compact tapered slot antennas for UWB microwave imaging applications

This paper presents the design of compact Tapered Slot Antennas (TSAs) for application in an Ultra Wide Band (UWB) microwave imaging system. In the initial step, a conventional size-reduced TSA with an exponential taper for 3.1-10.6 GHz band is designed. From the radiation pattern analysis, it is found that this antenna exhibits poor directivity in the lower part of UWB. To overcome this shortfall, two modifications are investigated. One includes corrugations and the other one elliptical cuts on sides of the initial TSA. It is shown that the modified TSAs feature improved directivity while their UWB impedance characteristics are similar to the original TSA. The TSA with corrugations exhibits an almost constant directive radiation pattern across UWB. However, its gain oscillates with frequency leading to a pulse distortion. Therefore the size-reduced TSA with elliptical cuts in conducting sides looks to be the most attractive choice with respect to both directive properties and distortionless pulse transmission

Novel image reconstruction algorithm for a UWB cylindrical microwave imaging system

A theoretical and experimental study of a novel image reconstruction algorithm for an Ultra Wide band (UWB) Microwave Imaging System aiming at detecting and locating small targets in a homogenous circular cylindrical dielectric body is presented. The system uses a double circular scan in which the second scan is achieved after rotating by a small angle the antenna sub-system or the imaged body. The obtained two sets of data serve the purpose of subtracting the background that masks the target. Assuming that the target is asymmetric with respect to the axis of rotation, the difference data includes the original target and its negative "ghost". In order to eliminate the "ghost" only the positive valued difference data is extracted. This data is scaled and mapped to show the original target location. The validity of the proposed image reconstruction algorithm is demonstrated in an example of a cylindrical plastic container filled with a vegetable oil and small cylindrical targets. © 2010 IEEE

Dielectric properties assessment of honey by using non-destructive dielectric spectroscopy

In this research the dielectric constant of three types of Malaysian honey has been investigated using a non-destructive measurement technique. The objective of this research is to assess the dielectric constant of the three types of honey in Malaysia using a non-destructive measurement technique known as an open-ended coaxial probe in the frequency range from 100 MHz to 10 GHz frequency. Analysis on the effect water concentration in honey on the dielectric constant and the effect of temperature on dielectric constant of honey has been conducted. The three types of honey that have been chosen to be investigated in this project are stingless bee honey, wild honey and commercial (organic) honey and together their water adulterated samples. For this research, the probe had been set up by setting a range of frequency from 100 MHz to 10 GHz and needs to be calibrated with three calibration methods namely open, short and reference water. From the result it was found that the higher the temperature of the honey and the higher percentage of water content in the honey, the dielectric constant is increased. The dielectric constants of all honeys decreased with increasing frequency in the measured frequency range and increased with increase percentage of water content and temperature

Wireless Power Transfer via Inductive Coupling

Various types of wireless power transfer method have been developed in recent years. This technology has eventually impacted the human life, especially the way they harvest the electrical energy resources. The most common and the first technology of wireless power created are known as inductive coupling method, which transfers power using magnetism process. This paper proposes the design of an oscillator that produces oscillation frequency at 1MHz for nearfield wireless power transfer, and it is applicable for a short range wireless power transmission only. In conjunction to that, this paper also presents a design of the resonator of an antenna using copper wire in transmitting and receiving the energy transfer for short range transmission of wireless power transfer. The proposed design uses the concept of pad charger where the coil is designed from a pancake coil properties known as flat circular coil. The coil acts as an antenna and magnetic coupled or electromagnetic induced such that when there are changes of current occur in one coil, it will induce the voltage at the other end of the coil, in which the wireless power is transferred between the transmitter and the receive. It can be concluded in this proposed method has the ability to successfully transfer the power between the transmitter and the receiver, even when some obstacles are placed between the coil antennas. Then, a rectifier was used at the receiver to convert the alternating received current to the direct current. The received power is measured to observe the variations at several distances

A Fluorine-19 Magnetic Resonance Probe, Shiga-Y5, Downregulates Thioredoxin-Interacting Protein Expression in the Brain of a Mouse Model of Alzheimer\u27s Disease.

Thioredoxin-interacting protein (TXNIP) is involved in multiple disease-associated functions related to oxidative stress, especially by inhibiting the anti-oxidant- and thiol-reducing activity of thioredoxin (TXN). Shiga-Y5 (SY5), a fluorine-19 magnetic resonance probe for detecting amyloid-β deposition in the brain, previously showed therapeutic effects in a mouse model of Alzheimer\u27s disease; however, the mechanism of action of SY5 remains unclear. SY5 passes the blood-brain barrier and then undergoes hydrolysis to produce a derivative, Shiga-Y6 (SY6), which is a TXNIP-negative regulator. Therefore, this study investigates the therapeutic role of SY5 as the prodrug of SY6 in the thioredoxin system in the brain of a mouse model of Alzheimer\u27s disease. The intraperitoneal injection of SY5 significantly inhibited TXNIP mRNA (p = 0.0072) and protein expression (p = 0.0143) induced in the brain of APP/PS1 mice. In contrast, the levels of TXN mRNA (p = 0.0285) and protein (p = 0.0039) in the brain of APP/PS1 mice were increased after the injection of SY5. The ratio of TXN to TXNIP, which was decreased (p = 0.0131) in the brain of APP/PS1 mice, was significantly increased (p = 0.0072) after the injection of SY5. These results suggest that SY5 acts as a prodrug of SY6 in targeting the thioredoxin system and could be a potential therapeutic compound in oxidative stress-related diseases in the brain

Pharmaceutical Potential of Casein-Derived Tripeptide Met-Lys-Pro: Improvement in Cognitive Impairments and Suppression of Inflammation in APP/PS1 Mice

Background:Tripeptide Met-Lys-Pro (MKP), a component of casein hydrolysates, has effective angiotensin-converting enzyme (ACE) inhibitory activity. Brain angiotensin II enzyme activates the NADPH oxidase complex via angiotensin II receptor type 1 (AT1) and enhances oxidative stress injury. ACE inhibitors improved cognitive function in Alzheimer\u27s disease (AD) mouse models and previous clinical trials. Thus, although undetermined, MKP may be effective against pathological amyloid-β (Aβ) accumulation-induced cognitive impairment.Objective:The current study aimed to investigate the potential of MKP as a pharmaceutical against AD by examining MKP\u27s effect on cognitive function and molecular changes in the brain using double transgenic (APP/PS1) mice.Methods:Experimental procedures were conducted in APP/PS1 mice (n = 38) with a C57BL/6 background. A novel object recognition test was used to evaluate recognition memory. ELISA was used to measure insoluble Aβ40, Aβ42, and TNF-α levels in brain tissue. Immunohistochemical analysis allowed the assessment of glial cell activation in MKP-treated APP/PS1 mice.Results:The novel object recognition test revealed that MKP-treated APP/PS1 mice showed significant improvement in recognition memory. ELISA of brain tissue showed that MKP significantly reduced insoluble Aβ40, Aβ42, and TNF-α levels. Immunohistochemical analysis indicated the suppression of the marker for microglia and reactive astrocytes in MKP-treated APP/PS1 mice.Conclusion:Based on these results, we consider that MKP could ameliorate pathological Aβ accumulation-induced cognitive impairment in APP/PS1 mice. Furthermore, our findings suggest that MKP potentially contributes to preventing cognitive decline in AD