238 research outputs found

    New Compact Wideband Microstrip Antenna for Wireless Applications

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    In this paper, a miniature rectangular microstrip antenna over partial ground plane is presented by utilizing a space-filling property of fractal geometry in this design. It is simulated by High Frequency Software Simulator (HFSS) software, fabricated and tested by Vector Network Analyzer (VNA).Two types of slots are introduced in order to enhance antenna parameters such as bandwidth and return loss S1.1. This antenna is fabricated on FR4 substrate with a small size of (18 x 16 x 1.5) mm3, 1.5mm substrate thickness, 4.3 permittivity and 0.02 loss tangent. To feed this antenna,  microstrip line feed is used. This antenna is implemented for wide bandwidth (4.8-11.6) GHz, and has three resonant frequencies at 5.5GHz, 8.3GHz and 10.7GHz with impedance bandwidth of 6.8GHz. The gap value g between partial ground plane and rectangular patch at top layer is optimized in order to achieve optimal simulated return loss S1.1 is (-46,-32,-14) dB at three resonant frequencies (5.5, 8.3, 10.7) GHz and optimal radiation efficiency of 93.42% with gain of 3.63dB. The simulated results have tolerable agreement with measured results. This antenna is suitable for wireless computer applications within  C and X band  communications

    Miniaturized Wideband Microstrip Antenna for Recent Wireless Applications

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    In this paper, a pentagon slot inside fractal circular patch microstrip resonator to design compact antenna over partial ground plane is introduced using 3rd iteration of adopted fractal geometry. This antenna is modeled on FR4 substrate with a size of (20 x 18) mm2, thickness of 1.5mm, permittivity of 4.3 and loss tangent of 0.02. The used type of feeding is microstrip line feed. It is designed to operate at wide frequency range of (4.5-9.3) GHz at resonant frequencies of 5.7GHz and 7.9GHz with impedance bandwidth of 4.8 GHz. Both lengths of ground plane Lg and width of feed line Wf are optimized in order to acquire optimum bandwidth. The simulated return loss values are -33 and -41 dB at two resonant frequencies of 5.7 and 7.9 GHz with gain of 3.2 dB. The simulated results offered noteworthy compatibility with measured results. Also, the proposed wideband microstrip antenna has substantial compactness that can be integrated within numerous wireless devices and systems

    In vitro, Alternative Methods to the Biological Control of the Aphids by Entomopathogenic Fungi Beauveria bassiana Isolates from Gaza Strip

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    Sustainable vegetable production it depends mainly on yield and quality, if not properly managed, pests and diseases can dramatically reduce crop yield, quality and subsequent returns. Plant diseases need to be controlled to maintain the quality and abundance of food, feed, and fiber produced by growers around the world (Pal and Gardener, 2006). Disease control is an essential component of crop management for increase yield potential. A low disease loss in your fields in the recent past does not ensure disease losses will remain low (Tobacco disease management (2015). Every year gardeners confront many insect pests feasting on fruits and vegetables (Jackman, 1998). Plants have many pests, such as aphids and mites. Aphids are important herbivores of both wild and cultivated plants that feed on the phloem of vascular plants (Züst and Agrawal, 2016). Most vegetables crops attached by this pest and also it can stunt and distort the growth of plants and cause wilting and bud drop, resulting in poor flowering and fruit set. Synthetic pesticides have played a central role for control plant pathogen (Chandler et al., 2011; El-Wakeil, 2013). In the recent years, the negative effects on health and the environment as a result of the indiscriminate use of pesticides have led the EU to the prohibition of many synthetic pesticides (D'Addabbo et al., 2014). Consequently

    Indoor environment propagation review

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    A survey of indoor propagation characteristics is presented, including different models for path loss, shadowing and fast fading mechanisms, different channel parameters including signal strength, power delay, coherence bandwidth, Doppler spread and angle of arrival. The concepts of MIMO channels are also covered. The study also explores many types of deterministic channel modelling, such as Finite Difference Time Domain, Finite Integration Method, Ray tracing and the Dominant path model. Electromagnetic properties of building materials, including frequency dependence, are also investigated and several models for propagation through buildings are reviewed

    ANTIBACTERIAL & ANTIFUNGAL POTENTIALITY OF RICINUS COMMUNIS & COLEUS FORSKOHLII ON SOME HUMAN PATHOGENIC MICROORGANISMS

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    The objective of the present study was to explore the antibacterial and antifungal activity of two plant extracts (Ricinus communis & Coleus forskohlii) against some selected pathogen (Staphylococcus aureus

    Activation Mobilizes the Cholesterol in the Late Endosomes-Lysosomes of Niemann Pick Type C Cells

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    A variety of intercalating amphipaths increase the chemical activity of plasma membrane cholesterol. To test whether intracellular cholesterol can be similarly activated, we examined NPC1 and NPC2 fibroblasts, since they accumulate large amounts of cholesterol in their late endosomes and lysosomes (LE/L). We gauged the mobility of intracellular sterol from its appearance at the surface of the intact cells, as determined by its susceptibility to cholesterol oxidase and its isotope exchange with extracellular 2-(hydroxypropyl)-β-cyclodextrin-cholesterol. The entire cytoplasmic cholesterol pool in these cells was mobile, exchanging with the plasma membrane with an apparent half-time of ∼3–4 hours, ∼4–5 times slower than that for wild type human fibroblasts (half-time ∼0.75 hours). The mobility of the intracellular cholesterol was increased by the membrane-intercalating amphipaths chlorpromazine and 1-octanol. Chlorpromazine also promoted the net transfer of LE/L cholesterol to serum and cyclodextrin. Surprisingly, the mobility of LE/L cholesterol was greatly stimulated by treating intact NPC cells with glutaraldehyde or formaldehyde. Similar effects were seen with wild type fibroblasts in which the LE/L cholesterol pool had been expanded using U18666A. We also showed that the cholesterol in the intracellular membranes of fixed wild-type fibroblasts was mobile; it was rapidly oxidized by cholesterol oxidase and was rapidly replenished by exogenous sterol. We conclude that a) the cholesterol in NPC cells can exit the LE/L (and the extensive membranous inclusions therein) over a few hours; b) this mobility is stimulated by the activation of the cholesterol with intercalating amphipaths; c) intracellular cholesterol is even more mobile in fixed cells; and d) amphipaths that activate cholesterol might be useful in treating NPC disease

    Systemic virus distribution and host responses in brain and intestine of chickens infected with low pathogenic or high pathogenic avian influenza virus

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    <p>Abstract</p> <p>Background</p> <p>Avian influenza virus (AIV) is classified into two pathotypes, low pathogenic (LP) and high pathogenic (HP), based on virulence in chickens.</p> <p>Differences in pathogenicity between HPAIV and LPAIV might eventually be related to specific characteristics of strains, tissue tropism and host responses.</p> <p>Methods</p> <p>To study differences in disease development between HPAIV and LPAIV, we examined the first appearance and eventual load of viral RNA in multiple organs as well as host responses in brain and intestine of chickens infected with two closely related H7N1 HPAIV or LPAIV strains.</p> <p>Results</p> <p>Both H7N1 HPAIV and LPAIV spread systemically in chickens after a combined intranasal/intratracheal inoculation. In brain, large differences in viral RNA load and host gene expression were found between H7N1 HPAIV and LPAIV infected chickens. Chicken embryo brain cell culture studies revealed that both HPAIV and LPAIV could infect cultivated embryonic brain cells, but in accordance with the absence of the necessary proteases, replication of LPAIV was limited. Furthermore, TUNEL assay indicated apoptosis in brain of HPAIV infected chickens only. In intestine, where endoproteases that cleave HA of LPAIV are available, we found minimal differences in the amount of viral RNA and a large overlap in the transcriptional responses between HPAIV and LPAIV infected chickens. Interestingly, brain and ileum differed clearly in the cellular pathways that were regulated upon an AI infection.</p> <p>Conclusions</p> <p>Although both H7N1 HPAIV and LPAIV RNA was detected in a broad range of tissues beyond the respiratory and gastrointestinal tract, our observations indicate that differences in pathogenicity and mortality between HPAIV and LPAIV could originate from differences in virus replication and the resulting host responses in vital organs like the brain.</p
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