61 research outputs found
GeVn complexes for silicon-based room-temperature single-atom nanoelectronics
We characterize germanium-vacancy GeVn complexes in silicon using
first-principles Density Functional Theory calculations with
screening-dependent hybrid functionals. We report on the local geometry and
electronic excited states of these defects, including charge transition levels
corresponding to the addition of one or more electrons to the defect. Our main
theoretical result concerns the GeV complex, which we show to give rise to two
excited states deep in the gap, at -0.51 and -0.35 eV from the conduction band,
consistently with the available spectroscopic data. The adopted theoretical
scheme, suitable to compute a reliable estimate of the wavefunction decay,
leads us to predict that such states are associated to an electron localization
over a length of about 0.45 nm. By combining the electronic properties of the
bare silicon vacancy, carrying deep states in the band gap, with the spatial
controllability arising from single Ge ion implantation techniques, the GeVn
complex emerges as a suitable ingredient for silicon-based room-temperature
single-atom devices
Microfluidic cell engineering on high-density microelectrode arrays for assessing structure-function relationships in living neuronal networks
Neuronal networks in dissociated culture combined with cell engineering
technology offer a pivotal platform to constructively explore the relationship
between structure and function in living neuronal networks. Here, we fabricated
defined neuronal networks possessing a modular architecture on high-density
microelectrode arrays (HD-MEAs), a state-of-the-art electrophysiological tool
for recording neural activity with high spatial and temporal resolutions. We
first established a surface coating protocol using a cell-permissive hydrogel
to stably attach polydimethylsiloxane microfluidic film on the HD-MEA. We then
recorded the spontaneous neural activity of the engineered neuronal network,
which revealed an important portrait of the engineered neuronal
network--modular architecture enhances functional complexity by reducing the
excessive neural correlation between spatially segregated modules. The results
of this study highlight the impact of HD-MEA recordings combined with cell
engineering technologies as a novel tool in neuroscience to constructively
assess the structure-function relationships in neuronal networks.Comment: 18 pages, 5 figure
Green Tea Epigallocatechin Gallate Exhibits Anticancer Effect in Human Pancreatic Carcinoma Cells via the Inhibition of Both Focal Adhesion Kinase and Insulin-Like Growth Factor-I Receptor
The exact molecular mechanism by which epigallocatechin gallate (EGCG) suppresses human pancreatic cancer cell proliferation is unclear. We show here that EGCG-treated pancreatic cancer cells AsPC-1 and BxPC-3 decrease cell adhesion ability on micro-pattern dots, accompanied by dephosphorylations of both focal adhesion kinase (FAK) and insulin-like growth factor-1 receptor (IGF-1R) whereas retained the activations of mitogen-activated protein kinase and mammalian target of rapamycin. The growth of AsPC-1 and BxPC-3 cells can be significantly suppressed by EGCG treatment alone in a dose-dependent manner. At a dose of 100 μM which completely abolishes activations of FAK and IGF-1R, EGCG suppresses more than 50% of cell proliferation without evidence of apoptosis analyzed by PARP cleavage. Finally, the MEK1/2 inhibitor U0126 enhances growth-suppressive effect of EGCG. Our data suggests that blocking FAK and IGF-1R by EGCG could prove valuable for targeted therapy, which can be used in combination with other therapies, for pancreatic cancer
Measuring Relative-Story Displacement and Local Inclination Angle Using Multiple Position-Sensitive Detectors
We propose a novel sensor system for monitoring the structural health of a building. The system optically measures the relative-story displacement during earthquakes for detecting any deformations of building elements. The sensor unit is composed of three position sensitive detectors (PSDs) and lenses capable of measuring the relative-story displacement precisely, even if the PSD unit was inclined in response to the seismic vibration. For verification, laboratory tests were carried out using an Xθ-stage and a shaking table. The static experiment verified that the sensor could measure the local inclination angle as well as the lateral displacement. The dynamic experiment revealed that the accuracy of the sensor was 150 μm in the relative-displacement measurement and 100 μrad in the inclination angle measurement. These results indicate that the proposed sensor system has sufficient accuracy for the measurement of relative-story displacement in response to the seismic vibration
HIGH-RESOLUTION SUBMILLIMETER AND NEAR-INFRARED STUDIES OF THE TRANSITION DISK AROUND Sz 91
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