Chemical Composition and Antioxidant Activity of seeds oils and fruit juice of Opuntia Ficus Indica and Opuntia Dillenii from Morocco

peer reviewedThis study provides basic information on the mineral composition of the seeds and antioxidant activity in seeds oils and fruit juices of cactus belonging to two species Opuntia ficus indica and Opuntia dillenii, from Morocco (Oujda), in order to evaluate the nutritional value of the Opuntia extracts. Minerals determined from dry seeds of Opuntia ficus indica and Opuntia dillenii were: calcium 480.93 and 408.28; phosphorus 1417.59 and 970.15; potassium 304.51 and 201.96; magnesium: 316.59 and 240.30; sodium: 48.33 and 18.18; zinc: 70.77 and 78.26 mg/100g respectively. The main fatty acids of Opuntia ficus indica and Opuntia dillenii seed oil were respectively: linoleic acid: 58.79 and 79.83%, Palmitic acid: 11.18 and 13.52%. The antioxidant activity of Opuntia ficus indica and Opuntia dillenii seed oils and fruit juices were assessed by means of 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging assay and ascorbic acid test. The results showed that the antioxidant activities of Opuntia ficus indica and Opuntia dillenii seed oil (IC50 = 19.79 ± 0.023 and 27.21 ± 0.075 μL/mL) are higher than that of the reference ascorbic acid (IC50 = 16.56 ± 0.019 μg/mL). However, the Opuntia dillenii juice presents antioxidant activity more important than this of Opuntia seed oil and ascorbic acid. It possessed strong antioxidant activity (IC50 = 8.18 μL/mL). The antioxidant activity of the seed oil and juice were also found to be concentration-dependent

Spin-coated nickel doped cadmium sulfide thin films for third harmonic generation applications

In the current study, different percentages of Nickel (0%, 2%, 4% and 6%) doped CdS thin films have been deposited on glass substrates by the sol-gel spin-coating technique. Before performing the nonlinear optical studies, the structural, morphological and optical properties were examined as a function of Ni doping concentration through the XRD, SEM, AFM and UV–vis spectrometry, respectively. According to the XRD patterns, all films are polycrystalline and the incorporation of Ni does not change qualitatively the crystalline phase of CdS. The Ni doping affects the surface morphology of the CdS thin films which is indicated by scanning electron microscopy and atomic force microscopy images. The band gap was determined via the equation related to the absorption coefficient. It\u27s deduced that the optical band-gap values increased from 2.35 eV to 2.41 eV depending on Ni content. Though, the nonlinear optical properties were determined based on the measurements of the third harmonic generation (THG) using the rotational Maker fringe technique. The results showed that the third order nonlinear optical susceptibilities oscillate between 5.40 × 10−21 m2/V2 for CdS:Ni (2%) and 4.98 × 10−21 m2/V2 for CdS:Ni (6%) while the pure CdS one falls inward, with a value of 5.09 × 10−21 m2/V2

Modified-Segmented Split-Ring Based Polarization and Angle-Insensitive Multi-Band Metamaterial Absorber for X, Ku and K Band Applications

A novel modified-segmented split-ring based symmetric metamaterial absorber is introduced in this paper for X, Ku, and K band applications. The perfect absorption was achieved with a total of 1.91 GHz absorption bandwidth using the conventional FR4 substrate without resistive lumped elements. EM waves were applied in TEM mode at both normal and oblique incidence up to 90° and the same absorptance was found at 11.23 GHz, 14.18 GHz, 17.37 GHz, and 19.18 GHz with the maximum of 85.51%, 99.13%, 98.19%, and 90.8% absorptance respectively. This absorption performance was proved for both co- and cross-polarization analysis. Double negative values of permittivity and permeability up to 17.37 GHz and single negative values of either permittivity or permeability at 19.18 GHz were achieved. An equivalent circuit analysis also proved its performance capability, which makes it a perfect metamaterial absorber. Finally, the comparison of the design with recently published works in terms of unit cell size, absorption band, maximum polarization angles, and cross-polarized absorptivity proved it as a better candidate for the potential use as a perfect absorber.This work was supported by the Science and Technology Unit, King Abdulaziz University, Saudi Arabia, under award number (Scopu

A planar ultrawideband patch antenna array for microwave breast tumor detection

In this paper, a compact planar ultrawideband (UWB) antenna and an antenna array setup for microwave breast imaging are presented. The proposed antenna is constructed with a slotted semicircular-shaped patch and partial trapezoidal ground. It is compact in dimension: 0.30λ × 0.31λ × 0.011λ, where λ is the wavelength of the lowest operating frequency. For design purposes, several parameters are assumed and optimized to achieve better performance. The prototype is applied in the breast imaging scheme over the UWB frequency range 3.10–10.60 GHz. However, the antenna achieves an operating bandwidth of 8.70 GHz (2.30–11.00 GHz) for the reflection coefficient under–10 dB with decent impedance matching, 5.80 dBi of maximum gain with steady radiation pattern. The antenna provides a fidelity factor (FF) of 82% and 81% for face-to-face and side-by-side setups, respectively, which specifies the directionality and minor variation of the received pulses. The antenna is fabricated and measured to evaluate the antenna characteristics. A 16-antenna array-based configuration is considered to measure the backscattering signal of the breast phantom where one antenna acts as transmitter, and 15 of them receive the scattered signals. The data is taken in both the configuration of the phantom with and without the tumor inside. Later, the Iteratively Corrected Delay and Sum (IC–DAS) image reconstructed algorithm was used to identify the tumor in the breast phantom. Finally, the reconstructed images from the analysis and processing of the backscattering signal by the algorithm are illustrated to verify the imaging performance.Funding: This work was made possible by NPRP12S-0227-190164 from the Qatar National Research Fund, a member of Qatar Foundation, Doha, Qatar. The statements made herein are solely the responsibility of the authors. The project was also funded by the Deanship of Scientific Research (DSR), King Abdulaziz University, Jeddah, Saudi Arabia under grant no. KEP-MSc-3-135-39. It was supported also by the Ministry of Education Malaysia research grant no. FRGS/1/2018/TK04/UKM/01/3.Scopu

Wearable smart sensor systems integrated on soft contact lenses for wireless ocular diagnostics

Wearable contact lenses which can monitor physiological parameters have attracted substantial interests due to the capability of direct detection of biomarkers contained in body fluids. However, previously reported contact lens sensors can only monitor a single analyte at a time. Furthermore, such ocular contact lenses generally obstruct the field of vision of the subject. Here, we developed a multifunctional contact lens sensor that alleviates some of these limitations since it was developed on an actual ocular contact lens. It was also designed to monitor glucose within tears, as well as intraocular pressure using the resistance and capacitance of the electronic device. Furthermore, in-vivo and in-vitro tests using a live rabbit and bovine eyeball demonstrated its reliable operation. Our developed contact lens sensor can measure the glucose level in tear fluid and intraocular pressure simultaneously but yet independently based on different electrical responses.ope

On the Radiation Resistance of a Planar Monopole Antenna With Reduced Groundplane

The radiation resistance of a short planar monopole antenna with a small ground plane is studied. The monopole of length /i h/ ( lambda /100 < /i h/ < lambda /10) is located orthogonally to the edge of a rectangular ground plane of length /i L/ and width /i W/. First, a parametric study is realized in order to determine the effect of the ground plane dimensions on the radiation resistance. Then, the two limit configurations, long and wide, are studied analytically with a model based on triangular current distributions, and comparisons to numerical results are shown. Finally, impedance matching by addition of one or two dipole arms is studied. We explain why this addition, besides reactance compensation, further increases the radiation resistance.Anglai

Experimental study of a 2D-irregular fractal-jet printed antenna

International audienc

Microwave conductivity measurements of high conductive polyaniline films

This paper presents several techniques for determining the complex conductivity of highly electrically conducting polymer films at microwave frequencies. The advantages and disadvantages of these techniques are discussed. Microwave measurements were investigated using resonant cavity, reflection/transmission and impedance surface techniques. The dc conductivity was measured using the four wires technique. Polyaniline (Pani/DEHEPSA) films of 120 $\mu$m thickness, have conductivity of (5000-6000 S/m) and permittivity of $6000 \pm 1000$ over X and S bands. The high values of the measured conductivity and its weak dependence on frequency at least up to 12 GHz, confirm the metallic character of Pani-films and their efficient use in micro-electronic technology such as microwave integrated circuits (MMIC) and microwave devices

Metasurface beam splitter based on all-dielectric elliptic resonators

© 2017 IEEE. We describe an all-dielectric metasurface, based on elliptic dielectric resonators (EDRs), which is designed to work as a beam splitter at 16.98 GHz. The proposed metasurface refracts electromagnetic incident waves with orthogonal polarizations along two specific directions without reflection