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A Radix Notoginseng flavonol glycoside (RNFG), quercetin 3-O-beta-D-xylopyranosyl-beta-D-galactopyranoside, was isolated from roots of Panax notoginseng. Among different biological properties tested, RNFG possessed a strong activity in preventing amyloid-beta (A beta)-induced cell death. In an in vitro assay, RNFG inhibited the aggregation of A beta in a dose-dependent manner. Moreover, application of RNFG in cultured cortical neurons, or PC12 cells, reduced the A beta-induced cell death in time-and dose-dependent manners, with the suppression of A beta-induced DNA fragmentation and caspase-3 activation. In cultured neurons, the pre-treatment of RNFG abolished the increase of Ca2+ mobilization triggered by A beta. The neuroprotective properties of RNFG required a specific sugar attachment within the main chemical backbone because the flavonol backbone by itself did not show any protective effect. In memory impairment experiments using the passive avoidance task, the administration of RNFG reduced brain damage in scopolamine-treated rats. These results therefore reveal a novel function of Radix Notoginseng and its flavonol glycoside that could be very useful in developing food supplements for the prevention, or potential treatment, of Alzheimer's disease.

Bis(7)-tacrine, a promising anti-Alzheimer's dimer, has been shown to have multiple neuroprotective activities in vitro. Here, we investigate whether bis(7)-tacrine attenuates focal cerebral ischemic impairment in vivo. Cerebral ischemia was induced in Sprague-Dawley rats by transient (2 h) middle cerebral artery occlusion (MCAO) followed by 24h of reperfusion. Bis(7)-tacrine administered intraperitoneally 15 min after ischemia dose-dependently improved neurological behavior deficits and reduced both cerebral infarct volume and edema. The TUNEL staining assay showed that bis(7)-tacrine attenuated neuronal apoptosis in the penumbral region. Compared with that for memantine, a moderately effective N-methyl-D-aspartate (NMDA) receptor antagonist with a similar affinity and potency to bis(7)-tacrine in blocking NMDA receptors, the therapeutic window for bis(7)-tacrine was wider and lasted up to 6 h after the onset of ischemia. Bis(7)-tacrine did not affect physiological parameters or regional cerebral blood flow during either the occlusion period or the early reperfusion stage. In conclusion, bis(7)-tacrine close- and time-dependently protected against acute focal cerebral ischemic insults, possibly through the drug's anti-apoptotic effects during multiple events in the ischemic cascade. (C) 2008 Elsevier Ireland Ltd. All rights reserved.

This report discusses the Phase I results in achieving light emission from Erbium doped Gallium Nitride materials. Erbium is a rare earth material which can emit at specific wavelengths of light, both in the visible and infrared regions of the spectrum. Erbium-doped layers were grown in GaN-based junctions by the molecular beam processing technique. The effects of Erbium in GaN were characterized using photoluminescence (PL) and catholuminescence (CL). Prototype devices were fabricated and electrically pumped light emission from the Er LEDs was observed.

InP-based materials enable optoelectronic and high speed devices. InP structures are limited in a real size, which greatly adds to the cost of InP devices. Conversely, silicon wafers are an order of magnitude larger and less costly. This STTR program seeks to create device quality InP layers on silicon substrates. The lattice mismatch between Si and InP would normally create defects in the crystal and result in poor material quality. To achieve good InP growth, a thin oxide buffer layer is grown on top of the Si prior to the InP. This oxide layer absorbs the strain mismatch between the two materials. The Phase I has demonstrated InP on Silicon with good structural and optical quality. Optimization of the process will be conducted in Phase II.

Report developed under SBIR contract for topic AF99-163. Due to the lack of availability of suitable GaSb substrates our strategy has been to make suitable buffer layers on the semi-insulating GaAs substrates before the superlattices are grown. Although significant progress was made to produce reasonable quality (111) superlattice samples, further improvement is necessary to reach the level of the (100) superlattices. Interpretation of the measurement result is thus in part affected by the relatively high level of defects in these samples, and decisive comparison can not yet be made between the two crystalline orientations. Nonetheless a systematic study has been carried out which resulted in producing bandedge transmission as long as 15 micrometers. Many samples exhibiting 8-12 micrometers have been demonstrated. We are hopeful with improving growth techniques the theoretical prediction for these (111) superlattices may be realized.

The objective of the ultra-sensitive Laser-Ionization for Real-Time Analysis Control (ULTRA) program was to develop and advanced growth diagnostics instrument for molecular beam epitaxy (MBE) systems which will provide date during material deposition of growth species fluxes and epitaxial growth rate in the most non-intrusive manner possible. This program was a cooperative "team" effort between SVT Associates and researchers at the University of Colorado, Boulder and the University of California, Los Angeles. In this report we will discuss the progress made in specific tasks outlined for this three year program. The highlights of this program are the following Optimized Ultra Tool by implementation of high quality laser and optics: factor of five increase in 9th harmonic (118nm) generation; low cost atomic resonance lamps examined as alternative VUV source; optimization of Time-of-Flight (TOF) hardware; quantification of the detection efficiency of flux species. Implemented Sensor Suite for MBE Process: implementation of prototype ULTRA on deposition systems; development of optical scattering and advanced pyrometry tools; interface-capability to process automation software control. Developed Fabrication Process of Nano-structures: surface dynamics study of GaAs homoepitaxy; InAs quantum dot growth on GaAs; SiGe nano-structure fabrication as function of flux and temperature; investigation of the effect of surfactants., Prepared in collaboration with Colorado Univ.at Boulder, Boulder, CO., and California Univ., Los Angeles, CA.

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We have investigated flux transients in Molecular Beam Epitaxy (MBE) sources. A detailed study of the relevant factors has been carried out. For the first time Ga transient was measured in the presence of as in a realistic growth environment. Growth rate variation due to transients can be accurately monitored by RHEED analysis. We demonstrated that transients could be minimized or even eliminated by source temperature ramping and mass spectrometer feedback control.

Nanosecond time-resolved emission spectral techniques have been applied to the problem of the origin and nature of the well-known temperature-dependent spectral shifts characteristic of the aminophthalimides in alcohol solvents. It is demonstrated that the temperature-dependent spectral shifts are in fact due to time-dependent spectral shifts. At least two relaxation times characterize this phenomenon. One relaxation time is observed to be subnanosecond in character and may be associated with the exciplex that presumably is present in the system. The other relaxation time is presumably associated with the non-specific dipolar reorientation although it has distinctly different characteristics from the solvent dielectric relaxation time. Wavelength-dependent fluorescence decay that can be explained by the time dependence of the emission spectrum is also observed. (Author)

A report is given of an investigation of the temperature-dependent emission spectral shifts of aminophthalimide in propanol by (1) time resolved emission spectroscopy on a nanosecond time scale, and (2) fluorescence decay studies as a function of emission wavelength across the emission band.