Nicotine administration reduces appetite and alters feeding patterns; a major deterrent to smoking cessation is hyperphagia and resultant weight gain. We demonstrate here that lateral hypothalamic (LH) circuits involving melanin-concentrating hormone (MCH) neurons are subject to cholinergic modulation that may be related to the effects of nicotine on appetite control. Cholinergic input to the p...

We examine defect modes in four-section helical hotonic crystals (HPCs) that comprise three twist defects located at the intersections. The three twist defects are introduced by a single angle phit , but they are quantified differently by the jump angles across the successive sections. The two defect modes are localized at the different defect sites and can be either coupled or uncoupled to eac...

We demonstrate that left-handed resonance transmission from metallic metamaterial, composed of periodically arranged double rings, can be extended to visible spectrum by introducing an active medium layer as the substrate. The severe ohmic loss inside metals at optical frequencies is compensated by stimulated emission of radiation in this active system. Due to the resonance amplification mechan...

Composite rightand left-handed (CRLH) transmission lines with regularly spaced Schottky varactors are characterized for propagation of short envelope pulses. Due to strong dispersion, a short pulse cannot travel on a conventional CRLH line without distortion. This distortion is compensated for by the effects of Schottky varactors such that the line supports solitonic pulses, whose pulse width d...

We perform a theoretical investigation on the Goos-Häenchen shift (the lateral shift) in one-dimensional photonic crystals (1DPCs) containing left-handed (LH) metamaterials. The effect was studied by use of a Gaussian beam. We show that the giant lateral displacement is due to the localization of the electromagnetic wave which can be both positive and negative depending on the incidence angle o...

A compact circularly polarized (CP) patch antenna using a composite right/left-handed (CRLH) transmission line (TL) unit-cell is proposed. The CRLH TL unitcell includes a complementary split ring resonator (CSRR) for shunt inductance and a gap loaded with a circularshaped slot for series capacitance. The CSRR can decrease the TM10 mode resonance frequency, thus reducing the electrical size of t...

Metamaterials are an active area of interest currently due to their exotic electromagnetic properties not readily found in nature. In this report, the transmission line approach is used to design a Complementary Right Left Handed (CRLH) Transmisssion line. The characteristics of a modulated pulse propagation are studied. We look at how the variation of pulse width, centre frequency and pulse re...

Prism coupling and reflection spectroscopy are used to characterize bound modes within composite right/left handed terahertz metamaterial waveguides. The cavity antenna model is used to understand the polarization dependence of the radiative coupling to TM00 and TM01 waveguide modes. Furthermore, the cavity model along with transmission-line theory is used to derive a surface impedance model fo...