37 research outputs found
Epitaxial growth and characterization of multi-layer site-controlled InGaAs quantum dots based on the buried stressor method
We report on the epitaxial growth, theoretical modeling, and structural as
well as optical investigation of multi-layer, site-controlled quantum dots
fabricated using the buried stressor method. This advanced growth technique
utilizes the strain from a partially oxidized AlAs layer to induce
site-selective nucleation of InGaAs quantum dots. By implementing
strain-induced spectral nano-engineering, we achieve separation in emission
energy by about 150 meV of positioned and non-positioned quantum dots and a
local increase of the emitter density in a single layer. Furthermore, we
achieve a threefold increase of the optical intensity and reduce the
inhomogeneous broadening of the ensemble emission by 20% via stacking three
layers of site-controlled emitters, which is particularly valuable for using
the SCQDs in microlaser applications. Moreover, we obtain direct control over
emission properties by adjusting the growth and fabrication parameters. Our
optimization of site-controlled growth of quantum dots enables the development
of photonic devices with enhanced light-matter interaction and microlasers with
increased confinement factor and spontaneous emission coupling efficiency
Quantitative methylation profiling in tumor and matched morphologically normal tissues from breast cancer patients
Effects of cell seeding density on real-time monitoring of anti-proliferative effects of transient gene silencing
WOS: 000390112500001PubMed ID: 27981039Background: Real-time cellular analysis systems enable impedance-based label-free and dynamic monitoring of various cellular events such as proliferation. In this study, we describe the effects of initial cell seeding density on the anti-proliferative effects of transient gene silencing monitored via real-time cellular analysis. We monitored the realtime changes in proliferation of Huh7 hepatocellular carcinoma and A7r5 vascular smooth muscle cells with different initial seeding densities following transient receptor potential canonical 1 (TRPC1) silencing using xCELLigence system. Huh7 and A7r5 cells were seeded on E-plate 96 at 10,000, 5000, 1250 and 5000, 2500 cells well(-1), respectively, following silencing vector transfection. The inhibitory effects of transient silencing on cell proliferation monitored every 30 min for 72 h. Results: TRPC1 silencing did not inhibit the proliferation rates of Huh7 cells at 10,000 cells well(-1) seeding density. However, a significant anti-proliferative effect was observed at 1250 cells well(-1) density at each time point throughout 72 h. Furthermore, significant inhibitory effects on A7r5 proliferation were observed at both 5000 and 2500 cells well(-1) for 72 h. Conclusions: Data suggest that the effects of transient silencing on cell proliferation differ depending on the initial cell seeding density. While high seeding densities mask the significant changes in proliferation, the inhibitory effects of silencing become apparent at lower seeding densities as the entry into log phase is delayed. Using the optimal initial seeding density is crucial when studying the effects of transient gene silencing. In addition, the results suggest that TRPC1 may contribute to proliferation and phenotypic switching of vascular smooth muscle cells.Scientific and Technological Research Council of Turkey (TUBITAK Research Project)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [108S072]; Novartis (Turkey)Novartis; Research Infrastructure Project, The State Planning Organization of Turkey (DPT) [2009K120640]This work was supported by The Scientific and Technological Research Council of Turkey (TUBITAK Research Project, 108S072) and Novartis (Turkey) to MT. The xCELLigence system was purchased within the Research Infrastructure Project, The State Planning Organization of Turkey (DPT, 2009K120640)