281 research outputs found

    CRLH Transmission Lines for Telecommunications: Fast and Effective Modeling

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    A different parameter extraction approach based on zero immittances for composite right/left-handed (CRLH) structure is presented. For lossless unit cell equivalent circuit model, LC parameters of series and parallel branches are extracted according to series resonance frequency and parallel resonance frequency, respectively. This approach can be applied to symmetric and unbalanced CRLH structures. The parameter extraction procedure is provided and validated by T-type unit cell model. The responses of distributed prototype and extracted equivalent LC circuit model are in good agreement. The equivalent circuit modeling can improve the degree of freedom in the CRLH TLs design. This parameter extraction method provides an effective and straightforward way in CRLH metamaterials design and applications in telecommunication systems

    Anticonvulsant and sedative effect of Fufang Changniu pills and probable mechanism of action in mice

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    Purpose: To investigate the anticonvulsant and sedative effects of Fufang Changniu Pills (FCP) and its probable mechanism of action in mice.Methods: The water decoction of FCP was prepared and the main constituents were determined by high performance liquid chromatography (HPLC). The anticonvulsant activities of FCP were evaluated by maximal electroshock (MES) and  pentylenetetrazole (PTZ)-induced seizures in mice. Pentobarbital sodium-induced sleeping time and locomotor activity measurements were performed to evaluate the sedative effects of FCP in mice. Finally, PTZ-induced chronic seizures were  established, and expressions of gamma-aminobutyric acid A receptor (GABA-A) and glutamic acid decarboxylase 65 (GAD65) in the brains of the mice were assayed by western blot in order to explore the probable mechanisms of action of the drug.Results: Gallic acid, liquiritin, cinnamyl alcohol, cinnamic acid and glycyrrhizic acid were detected in FCP decoction. FCP (50, 100 and 200 mg/kg) showed significant anticonvulsant and sedative effects on epileptic mice induced by MES (p < 0.05) and PTZ (p < 0.05). Moreover, pentobarbital sodium-induced sleeping time and  locomotor activity tests showed that FCP possesses sedative effect (p < 0.05). Western blot data indicate that FCP significantly up-regulated GABA-A and GAD 65 in the brains of chronic epileptic rats (p < 0.05).Conclusion: FCP has significant anticonvulsant and sedative effects, and the  mechanism of its action may be related to the up-regulation of GABA-A and GAD 65 in mice brain.Keywords: Epilepsy, Fufang Changniu pills, Anticonvulsant, Sedative effect,  Gamma-aminobutyric acid, Glutamate dehydrogenas

    Soluble epoxide hydrolase inhibitor promotes the healing of oral ulcers

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    Objective: Oral ulcers are a lesion in the oral mucosa that impacts chewing or drinking. Epoxyeicosatrienoic Acids (EETs) have enhanced angiogenic, regenerative, anti-inflammatory, and analgesic effects. The present study aims to evaluate the effects of 1-Trifluoromethoxyphenyl-3-(1-Propionylpiperidin-4-yl) Urea (TPPU), a soluble epoxide hydrolase inhibitor for increasing EETs level, on the healing of oral ulcers. Methods: The chemically-induced oral ulcers were established in Sprague Dawley rats. The ulcer area was treated with TPPU to evaluate the healing time and pain threshold of ulcers. The expression of angiogenesis and cell proliferation-related protein in the ulcer area was detected using immunohistochemical staining. The effects of TPPU on migration and angiogenesis capability were measured with scratch assay and tube formation. Results: Compared with the control group, TPPU promoted wound healing of oral ulcers with a shorter healing time, and raised pain thresholds. Immunohistochemical staining showed that TPPU increased the expression of angiogenesis and cell proliferation-related protein with reduced inflammatory cell infiltration in the ulcer area. TPPU enhanced cell migration and tube-forming potential in vitro. Conclusions: The present results support the potential of TPPU with multiple biological effects for the treatment of oral ulcers by targeting soluble epoxide hydrolase

    Domain control and periodic poling of epitaxial ScAlN

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    ScAlN is an emerging ferroelectric material that possesses large band gap, strong piezoelectricity, and holds great promises for enhanced \chi^{(2)} nonliearity. In this study, we demonstrate high-fidelity ferroelectric domain switching and periodic poling of Al-polar ScAlN thin film epitaxially grown on on c-axis sapphire substrate using gallium nitride as a buffer layer. Uniform poling of ScAlN with periods ranging from 2 um to 0.4 um is realized. The ability to lithographically control the polarization of epitaxial ScAlN presents a critical advance for its further exploitation in ferroelectric storage and nonlinear optics applications.Comment: 3 pages, 3 figure
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