Quintuple Band Antenna for Wireless Applications with Small Form Factor

RÉSUMÉ: A coplanar waveguide-fed quintuple band antenna with a slotted circular-shaped radiator for wireless applications with a high isolation between adjacent bands is presented in this paper. The proposed antenna resonates at multiple frequencies with corresponding center frequencies of 2.35, 4.92, 5.75, 6.52, and 8.46 GHz. The intended functionality is achieved by introducing a circular disc radiator with five slots and a U-shaped slot in the feed. The proposed antenna exhibits coverage of the maximum set of wireless applications, such as satellite communication, worldwide interoperability for microwave access, wireless local area network (WLAN), long-distance radio telecommunications, and X-band/Satcom wireless applications. The simulation and measurement results of the proposed fabricated antenna demonstrate the high isolation between adjacent bands. A stable realized gain with an advantageous radiation pattern is achieved at the operating frequency bands. The proposed simple design, compact structure, and simple feeding technique make this antenna suitable for integration in several wireless communication applications, where the portability of devices is a significant concern. The proposed antenna is anticipated to be an appropriate candidate for WLAN, long-term evolution, and fifth-generation mobile communication because of its multi-operational bands and compact size for handheld devices

Primary Medullary Hemorrhage Associated with Hypertension

Spontaneous primary medullary hemorrhage is a rare event. A 64-year-old man was admitted for sudden-onset vertigo and vomiting. His clinical features were similar to those of lateral medullary syndrome. The patient had no anticoagulant therapy, vascular malformation, or a caudal extension of a pontine hemorrhage. The patient had multiple hypertensive changes, including retinopathy, left ventricular hypertrophy on electrocardiography, multiple cerebral microbleeds, and small-vessel changes on MRI. T2*-weighted gradient echo MRI performed 3 months prior to admission and contrast-enhanced MRI showed no evidence of vascular malformation. We concluded that the patient had uncontrolled hypertension that may have lead to primary medullary hemorrhage

Removal of Pb(II) from aqueous solution by a zeolite–nanoscale zero-valent iron composite

The effectiveness of nanoscale zero-valent iron (nZVI) to remove heavy metals from water is reduced by its low durability, poor mechanical strength, and tendency to form aggregates. A composite of zeolite and nanoscale zero-valent iron (Z–nZVI) overcomes these problems and shows good potential to remove Pb from water. FTIR spectra support nZVI loading onto the zeolite and reduced Fe0 oxidation in the Z–nZVI composite. Scanning electron micrographs show aggregation was eliminated and transmission electron micrographs show well-dispersed nZVI in chain-like structures within the zeolite matrix. The mean surface area of the composite was 80.37 m2/g, much greater than zeolite (1.03 m2/g) or nZVI (12.25 m2/g) alone, as determined by BET-N2 measurement. More than 96% of the Pb(II) was removed from 100 mL of solution containing 100 mg Pb(II)/L within 140 min of mixing with 0.1 g Z–nZVI. Tests with solution containing 1000 mg Pb(II)/L suggested that the capacity of the Z–nZVI is about 806 mg Pb(II)/g. Energy-dispersive X-ray spectroscopy showed the presence of Fe in the composite; X-ray diffraction confirmed formation and immobilization of Fe0 and subsequent sorption and reduction of some of the Pb(II) to Pb0. The low quantity of Pb(II) recovered in water-soluble and Ca(NO3)2-extractable fractions indicate low bioavailability of the Pb(II) removed by the composite. Results support the potential use of the Z–nZVI composite in permeable reactive barriers

Removal of Pb(II) from aqueous solution by a zeolite–nanoscale zero-valent iron composite

The effectiveness of nanoscale zero-valent iron (nZVI) to remove heavy metals from water is reduced by its low durability, poor mechanical strength, and tendency to form aggregates. A composite of zeolite and nanoscale zero-valent iron (Z–nZVI) overcomes these problems and shows good potential to remove Pb from water. FTIR spectra support nZVI loading onto the zeolite and reduced Fe0 oxidation in the Z–nZVI composite. Scanning electron micrographs show aggregation was eliminated and transmission electron micrographs show well-dispersed nZVI in chain-like structures within the zeolite matrix. The mean surface area of the composite was 80.37 m2/g, much greater than zeolite (1.03 m2/g) or nZVI (12.25 m2/g) alone, as determined by BET-N2 measurement. More than 96% of the Pb(II) was removed from 100 mL of solution containing 100 mg Pb(II)/L within 140 min of mixing with 0.1 g Z–nZVI. Tests with solution containing 1000 mg Pb(II)/L suggested that the capacity of the Z–nZVI is about 806 mg Pb(II)/g. Energy-dispersive X-ray spectroscopy showed the presence of Fe in the composite; X-ray diffraction confirmed formation and immobilization of Fe0 and subsequent sorption and reduction of some of the Pb(II) to Pb0. The low quantity of Pb(II) recovered in water-soluble and Ca(NO3)2-extractable fractions indicate low bioavailability of the Pb(II) removed by the composite. Results support the potential use of the Z–nZVI composite in permeable reactive barriers

Throughput Analysis of Multipair Two-Way Replaying Networks With NOMA and Imperfect CSI

To improve the utilization of spectrum and system capacity, non-orthogonal multiple access (NOMA) is considered as a promising multiple access method for emerging communication technologies. Its advantageous benefits are implemented in two-way wireless networks. Power allocation factors assigned to multiple users play a key role in the successful deployment of fairness balance in NOMA. This paper considers fixed power allocation, and performance degradation is predicted in worse situation in which non-optimal power scheme and the imperfect channel state information (CSI) happen. More challenging issue happens in this system, and this paper addresses the situation of NOMA supporting multi-pair of users, in which group of users can communicate to other users to achieve acceptable throughout in two kinds of mode, i.e. delay-limited mode and delay-tolerant mode. Two performance metrics have been considered, namely, ergodic rate and outage probability. For both metrics, we derived closed-form analytical expressions as well as asymptotic performance. Numerical results show that the proposed system presents benefits to cellular networks by extending ability to serve more users who have different demands on data communication. Monte Carlo simulations are provided throughout to validate the accuracy of the derived analytical expressions

A Parametric Study on the Immunomodulatory Effects of Electroacupuncture in DNP-KLH Immunized Mice

This study was conducted to compare the effects of low frequency electroacupuncture (EA) and high frequency EA at acupoint ST36 on the production of IgE and Th1/Th2 cytokines in BALB/c mice that had been immunized with 2,4-dinitrophenylated keyhole limpet protein (DNP-KLH), as well as to investigate the difference in the immunomodulatory effects exerted by EA stimulations at acupoint ST36 and at a non-acupoint (tail). Female BALB/c mice were divided into seven groups: normal (no treatments), IM (immunization only), ST36-PA (IM + plain acupuncture at ST36), ST36-LEA (IM + low frequency (1 Hz) EA at ST36), ST36-HEA (IM + high frequency (120 Hz) EA at ST36), NA-LEA (IM + low frequency (1 Hz) EA at non-acupoint) and NA-HEA (IM + high frequency (120 Hz) EA at non-acupoint). EA stimulation was performed daily for two weeks, and total IgE, DNP-KLH specific IgE, IL-4 and IFN-γ levels were measured at the end of the experiment. The results of this study showed that the IgE and IL-4 levels were significantly suppressed in the ST36-LEA and ST36-HEA groups, but not in the NA-LEA and NA-HEA groups. However, there was little difference in the immunomodulatory effects observed in the ST36-LEA and ST36-HEA groups. Taken together, these results suggest that EA stimulation-induced immunomodulation is not frequency dependent, but that it is acupoint specific