We have examined in detail the optical properties of InGaN quantum wells ͑QWs͒ grown on pyramidal GaN mesas prepared by lateral epitaxial overgrowth ͑LEO͒ in a metalorganic chemical vapor deposition system that resulted in QWs on ͕1-101͖ facets. The effects of In migration during growth on the resulting QW thickness and composition were examined with transmission electron microscopy ͑TEM͒ and various cathodoluminescence ͑CL͒ imaging techniques, including CL wavelength imaging and activation energy imaging. Spatial variations in the luminescence efficiency, QW interband transition energy, thermal activation energy, and exciton binding energy were probed at various temperatures. Cross-sectional TEM was used to examine thickness variations of the InGaN/GaN QW grown on a pyramidal mesa. CL imaging revealed a marked improvement in the homogeneity of CL emission of the LEO sample relative to a reference sample for a conventionally grown In 0.15 Ga 0.85 N/GaN QW. The characteristic phase separation that resulted in a spotty CL image profile and attendant carrier localization in the reference sample is significantly reduced in the LEO QW sample. Spatial variations in the QW transition energy, piezoelectric field, and thermal activation energy were modeled using excitonic binding and transition energy calculations based on a single-band, effective-mass theory using Airy function solutions. Band-edge and effective-mass parameters were first obtained from a strain-and In-composition-dependent k"p calculation for wurtzite In x Ga 1Ϫx N, using a 6ϫ6 k"p Hamiltonian in the ͕1-101͖ representations. The calculations and experiments confirm a facet-induced migration of In during growth, which results in a smooth compositional variation from xϷ0.10 at the bottom of the pyramid to x Ϸ0.19 at the top. We demonstrate the existence of a strong correlation between the observed thermal activation behavior of QW luminescence intensity and the associated exciton binding energy for various positions along the pyramidal InGaN/GaN QWs, suggesting exciton dissociation is responsible for the observed temperature dependence of the QW luminescence in the ϳ150 to 300 K range.

Background:Axl plays multiple roles in tumourigenesis in several cancers. Here we evaluated the expression and biological function of Axl in renal cell carcinoma (RCC).Methods:Axl expression was analysed in a tissue microarray of 174 RCC samples by immunostaining and a panel of 11 normal tumour pairs of human RCC tissues by western blot, as well as in RCC cell lines by both western blot and quantitative PCR. The effects of Axl knockdown in RCC cells on cell growth and signalling were investigated. The efficacy of a humanised Axl targeting monoclonal antibody hMAb173 was tested in histoculture and tumour xenograft.Results:We have determined by immunohistochemistry (IHC) that Axl is expressed in 59% of RCC array samples with moderate to high in 20% but not expressed in normal kidney tissue. Western blot analysis of 11 pairs of tumour and adjacent normal tissue show high Axl expression in 73% of the tumours but not normal tissue. Axl is also expressed in RCC cell lines in which Axl knockdown reduces cell viability and PI3K/Akt signalling. The Axl antibody hMAb173 significantly induced RCC cell apoptosis in histoculture and inhibited the growth of RCC tumour in vivo by 78%. The hMAb173-treated tumours also had significantly reduced Axl protein levels, inhibited PI3K signalling, decreased proliferation, and induced apoptosis.Conclusions:Axl is highly expressed in RCC and critical for RCC cell survival. Targeting Axl is a potential approach for RCC treatment.

We have used spatially and temporally resolved cathodoluminescence ͑CL͒ to study the carrier recombination dynamics of InGaN quantum wells ͑QWs͒ grown on ͑0001͒-oriented planar GaN and ͕1101͖-oriented facets of GaN triangular prisms prepared by lateral epitaxial overgrowth in a metal-organic chemical vapor deposition system. The effects of In migration during growth on the resulting QW thickness and composition were examined. We employed a variable temperature time-resolved CL imaging approach that enables a spatial correlation between regions of enhanced exciton localization, luminescence efficiency, and radiative lifetime with the aim of distinguishing between excitons localized in In-rich quantum dots and those in the surrounding Ga-rich QW regions.

No abstract

A59 the multiplier effect. This novel approach highlighted the unique characteristics of Alzheimer's disease with particular focus on the additional costs and societal impact stemming from caring for a patient with Alzheimer's. Future cost effectiveness studies need to consider these additional impacts when quantifying their results and potential benefit to the health care system. Approaches to modelling long term disease impact must therefore be expanded to consider the wide reaching societal impact of Alzheimer's disease to the direct health care costs.

No abstract

Objectives The NEK2 (never in mitosis gene A-related kinase 2), a serine/threonine kinase involved in chromosome instability and tumorigenesis. Hence, this study aimed to explore the molecular function of NEK2 in esophageal squamous cell carcinoma (ESCC). Methods By available transcriptome datasets (GSE53625 cohort, GSE38129 cohort, and GSE21293 cohort), we analyzed the differentially expressed genes in invading and non-invading ESCC. Subsequently, we evaluated the association between NEK2 expression level and clinical outcomes through Kaplan–Meier analysis method. The quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting (WB) analyses were performed to determine the expression levels of NEK2 mRNA and protein, respectively. We knocked down the NEK2 expression in ESCC cells (ECA109 and TE1), and evaluated the NEK2 biology function associated with ESCC cell proliferation, migration, invasion, and colony formation abilities. Finally, the downstream pathway of NEK2 was analyzed through Gene Set Enrichment Analysis (GSEA) and validated the regulatory mechanism of NEK2 on the potential pathway through WB. Results We found that NEK2 was highly expressed in ESCC cells compared with human esophageal epithelial cells (HEEC) (P < 0.0001), and high NEK2 expression was remarkably associated with poor survival (P = 0.019). Knockdown of NEK2 showed the significant inhibitory effect for tumorigenesis, and suppressed the ESCC cells proliferation, migration, invasion, and formation of colonies abilities. Additionally, GSEA revealed that Wnt/β-catenin pathway was a downstream pathway of NEK2. WB results further validated the regulatory mechanism of NEK2 for Wnt/β-catenin signaling. Conclusions Our results indicated that NEK2 promotes ESCC cell proliferation, migration and invasion by activating the Wnt/β-catenin pathway. NEK2 could be a promising target for ESCC.

A multilayer buffer layer approach to GaN growth has been developed in which the thermal desorption and mass transport of low temperature buffer layer are minimized by deposition of successive layers at increased temperatures. High quality GaN with featureless surface morphology has been grown on (0001) sapphire substrate by metalorganic chemical vapor deposition using this multilayer buffer layer approach. The lateral growth and coalescence of truncated 3D islands (TTIs) nucleated on low temperature buffer layers at the initial stage of overlayer growth is affected by the thickness of the final buffer layer on which nucleation of TTIs takes place. The effect of the thickness of this buffer layer on the quality of GaN is studied by using scanning electron microscopy, van der Pauw geometry Hall measurements and cathodoluminescence and an optimum value of 400Å is obtained.