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Large-scale integrated quantum photonic technologies will require on-chip integration of identical photon sources with reconfigurable waveguide circuits. Relatively complex quantum circuits have been demonstrated already, but few studies acknowledge the pressing need to integrate photon sources and waveguide circuits together on-chip. A key step towards such large-scale quantum technologies is the integration of just two individual photon sources within a waveguide circuit, and the demonstration of high-visibility quantum interference between them. Here, we report a silicon-on-insulator device that combines two four-wave mixing sources in an interferometer with a reconfigurable phase shifter. We configured the device to create and manipulate two-colour (non-degenerate) or same-colour (degenerate) path-entangled or path-unentangled photon pairs. We observed up to 100.0 ± 0.4% visibility quantum interference on-chip, and up to 95 ± 4% off-chip. Our device removes the need for external photon sources, provides a path to increasing the complexity of quantum photonic circuits and is a first step towards fully integrated quantum technologies. [ABSTRACT FROM AUTHOR]

In the field of basic and clinical neurosciences, it is important to develop a method for easy delivery and persistent expression of transgene in central neurons. We firstly generated lentiviral vectors with five kinds of neuron-specific promoters, such as synapsin I (SYN), calcium/calmodulin-dependent protein kinase II, tubulin alpha I, neuron-specific enolase and platelet-derived growth factor beta chain promoters and then novel hybrid promoters by fusing cytomegalovirus enhancer (E) to those neuron-specific promoters. Neuron-specific expression of green fluorescent protein (GFP) with those promoters was examined in vivo by injecting the lentiviral vectors into the rat neostriatum, thalamus and neocortex. Among all the promoters, SYN promoter displayed the highest specificity for neuronal expression in all the regions examined (more than 96%). Although GFP production by the hybrid promoters was about 2–4 times larger than the non-enhanced promoters, the neuronal specificity was significantly decreased in most cases. However, the neuronal specificity of E/SYN hybrid promoter exhibited the least decrease only in the thalamus. Furthermore, the transcriptional activity and neuronal specificity of E/SYN promoter were sustained for up to 8 weeks. Thus, lentivirus with E/SYN promoter is the best vector for strong persistent expression in neurons.Gene Therapy (2007) 14, 872–882. doi:10.1038/sj.gt.3302924; published online 15 March 2007 [ABSTRACT FROM AUTHOR]

Microstructure, high-temperature compressive and tensile deformation, and corrosion property of multi-phase alloys based on Ni3Al-Ni3T1-Ni3Nb pseudo-ternary alloy system were investigated. The microstructures of these alloys were largely dependent on alloy composition but independent of annealing temperature. Alloys composed of multi-phase microstructures of L12, D024 and D0a showed substantially enhanced compressive yield stress as well as a certain amount of compressive plasticity at whole temperature, while they did not show reasonable tensile elongation at whole temperature. Also, alloys composed of lamellar-like multi-phase microstructures are effective in enhancing compressive yield stress particularly at high temperature. Multi-phase alloys with low Nb contents have good corrosion resistance, especially in high concentration of sulfuric acid. [ABSTRACT FROM AUTHOR]

Changes in gas-exchange rates during the life span of the leaves of rice ( Oryza sativa L.) were analyzed quantitatively by measuring changes in the carboxylation/oxygenation and regeneration of ribulose 1,5-bisphosphate (RuBP) at photon fluence rates of 2000 (saturating) and 500 (subsaturating) μmol quanta·m·s under ambient air conditions. The RuBP levels were always higher than the active-site concentrations of RuBP carboxylase (EC 4.1.1.39), irrespective of the irradiance supplied. Analysis of the CO-assimilation rate as a function of intercellular CO concentration indicated that RuBP regeneration does not limit CO assimilation. The estimated RuBP-carboxylase/oxygenase activity in vivo was linearly correlated to the rate of CO assimilation at each level of irradiance. This enzyme activity was just enough to account for the rate of CO assimilation at the saturating irradiance and was 35% more than the rate of CO assimilation at the subsaturating irradiance. Analysis of the assimilation rate at subsaturating irradiance as a function of intercellular CO concentration indicated that a limitation caused by enzyme activation comes into play. The results indicate that the rate of CO assimilation in rice leaves under ambient air conditions is limited during their entire life span by the RuBP-carboxylation/oxygenation capacity. [ABSTRACT FROM AUTHOR]