Design of Electrically Small Intraocular Antenna for Retinal Prosthesis System and Its Validation.

OBJECTIVE: This paper presents an ultra-miniaturized circular-shaped triple band microstrip antenna as an intraocular unit applicable for retinal prosthesis. METHODS: The reported antenna is developed by modifying a conventional circular-shaped patch with a pair of open-ended circular annular rings and a semicircular ring-loaded rectangular stub. Additionally, a shorting pin is used at the periphery of the patch to achieve the frequency bands of interest. Further, to make the structure electrically small and accommodate highly dense electrodes, the circular ground plane is modified by making symmetrical slots over the four quadrants and edges. Specific absorption rate distribution for 1g and 10g of different tissue layers over three operating frequencies has been studied by placing electromagnetic sources at different locations. RESULTS: With these arrangements, the proposed strip antenna offers multiband operation within the frequency band of 1.25 GHz (1.13-1.46 GHz), 2.45 GHz (2.24-2.66 GHz), and 3.32 GHz (3.09-3.50 GHz). Besides, circularly polarized radiation has also been achieved at 1.25 GHz with a 3-dB axial ratio bandwidth of 10 MHz. CONCLUSION: Finally, the proposed antenna structure is fabricated, and its measured performance metrics are in close aggreement with the simulated parameters. SIGNIFICANCE: The proposed antenna's performance inside a customized canonical eye model (DMCM) and anthropomorphic Zubal head model is studied and compared with the prior studies.

Recent Progress, Challenges, and Opportunities of Membrane Distillation for Heavy Metals Removal.

Water is essential for the presence of life on this earth. However, water contamination due to the presence of heavy/toxic metals is one of the serious environmental issues for living beings. Several methods have been devoted to separating or removing those heavy metals from wastewater. Among them, membrane distillation (MD) has become one of the most attractive approaches due to its higher rejection rate than processes driven by pressure, lower energy consumption than traditional distillation processes. MD has gained significant attention for removing heavy metals than other techniques like ion exchange and adsorption in the last two decades. This review provides insight knowledge to the reader and focuses on how heavy metals impact humans and the environment, sources of heavy metals, current and especially removal methods using the MD method. Moreover, recent studies, challenges, and opportunities on MD membrane modules and heavy metal removal systems are discussed. More importantly, in this review, we have identified the gaps and opportunities that are required for enhancing the MD approach and its practical suitability for heavy metal removals. MD module and system showed high performance, proving their possible applications to remove heavy metal ions in water/wastewater treatment.

The fabrication of a chemical sensor with PANI-TiO2 nanocomposites.

In this study, conjugated conducting polyaniline was fabricated onto titania nanoparticles (PANI-TiO2 NPs) using a microwave-accelerated reaction system. The synthesized nanoparticles were characterized using the techniques of electron microscopy (e.g., FE-SEM and TEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), and ultraviolet-visible (UV-Vis) spectrometry. An ultrasensitive sensor using the electrochemical (I-V) approach was fabricated using a thin film of PANI-TiO2 NPs on a glassy carbon electrode (GCE), and it was found to be selective towards 1,2-diaminobenzene (1,2-DAB) in a buffer phase. From current versus concentration studies, the calibration curve was plotted to estimate the sensor's analytical parameters. The highest sensitivity (19.8165 µA µM-1 cm-2) and lowest detection limit (0.93 ± 0.05 pM) were obtained from the electrochemical assessment by applying a signal-to-noise ratio of 3. A linear calibration plot was attained over a large range of concentration (LDR: 1.0 pM to 0.01 mM). The selective 1,2-DAB sensor was found to be efficient and reproducible in performance, yielding significant results with a fast response time (12.0 s). Therefore, the overall results of the 1,2-DAB chemical sensor suggest that this detection approach might be an easy way to develop an efficient electrochemical sensor for the protection of the environment as well as for use in the healthcare field on a broad scale.

Fabrication of 1,4-dioxane sensor based on microwave assisted PAni-SiO2 nanocomposites.

In this study, conducting polyaniline (PAni) and silicon dioxide (SiO2) nanocomposites (NCs) were synthesized for chemical sensing applications by microwave assisted reaction technique. Facile synthesis and characterization of the PAni-SiO2 nanocomposites were investigated in details and discussed in this report. For the potential application, 1,4-dioxane chemical sensor was fabricated with the PAni-SiO2 nanocomposites deposited onto glassy carbon electrode (GCE). A very thin uniform film was deposited onto GCE with nanocomposite by using conducting 5% nafion binder at room conditions. To evaluate the sensor analytical performances, a calibration plot such as current versus concentration of 1,4-dioxane was drawn and calculated the analytical parameters from the slope of calibration curve. Results are found as sensitivity (0.5934 µAµmol-1 L-2 cm-2), detection limit (16.0 ±â€¯0.8 pmol L-1), and quantification limit (LOQ; 53.3 ±â€¯1.5 pmol L-1) in this observation. Considering the linear region in calibration plot, the linear dynamic range of 1,4-dioxane chemical sensor was found (0.12 nmol L-1 ∼ 1.2 mmol L-1). Besides this, the proposed 1,4-dioxane chemical sensor was exhibited good reproducibility, long-term stability, high accuracy in detecting of 1,4-dioxane in real environmental samples. This research is to develop of a selective and an efficient electrochemical sensor. It might be a simple and easy way by applying electrochemical method to ensure the safe and sustainable green environment.