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This paper explores high efficiency of semiconductor grating structure at wavelength, 1550 nm for silicon on insulator (SOI) optical circuits. Here semiconductor grating structure is realized by the combination of silicon and compound semiconductor materials, where compound semiconductor gratings are envisaged by indium phosphide, Al 80 Ga 20 As and Al 42 Ga 58 As. Different types of losses in terms of absorption, reflection and diffraction including polarization are cogitated to investigate the efficiency of grating SOI structure at wavelength, 1550 nm. Interestingly, the absorption loss of above semiconductor grating is found to be zero at the above wavelength. Also the simulation was accomplished using plane wave expansion method, which leads to zero reflectance for the aforementioned structures at same wavelength. Simulation is also made for diffraction and polarization losses of above three semiconductor grating SOI structures. Simulation results reveal that diffraction efficiency is 1, (diffraction loss is zero) with respect to detune from Bragg’s angle which ranges from −12° to +12°. Additionally, the proposed structures encountered polarization losses. Present simulation results showed that polarization efficiency is more than 90% (polarization loss is less than 10%)in silicon −indium phosphide (Si-InP),silicon-Al 80 Ga 20 As (Si-Al 80 Ga 20 As) and silicon – Al 42 Ga 58 As (Si-Al 42 Ga 58 As) grating SOI structures with respect to same deviation. Since absorption, reflection and diffraction losses are zero, the overall transmitted efficiency depends on polarization efficiency and finally, with the combination of both absorption, reflection,diffraction and polarization loss,it is inferred that overall transmitted efficiency of semiconductor grating SOI structure is more than 90% with respect to same angle. [ABSTRACT FROM AUTHOR]

Hypertension affects approximately 60 million people in the United States. Recent studies have demonstrated that hypertension may produce progressive changes in the CNS. The present study is focused on reports in the literature that hypertension may significantly alter neurotransmitter systems, particularly dopamine (DA) and norepinephrine (NE). To address this, DA and norepinephrine (NE) receptor binding was assessed in the prefrontal cortex (PFC) of 15 male rhesus monkeys using on-the-slide in vitro assays for the DA1, NE α1 and NE α2 receptors as well as for the DA and NE uptake transporters. Eight monkeys underwent surgical coarctation of the mid-thoracic aorta which produced sustained, untreated hypertension as defined by a systolic pressure above 150 mm Hg. Compared with normotensive controls, chronic, untreated hypertension produced a significant decrease in DA1 and NE α1 receptor binding and an increase in DA uptake (DAU) receptor binding in the prefrontal cortex. While the mechanisms by which untreated hypertension alters DA and NE receptors is not known, the use of this non-human primate model should provide the means to uncover neurobiological changes that occur with untreated hypertension. [Copyright &y& Elsevier]