725 research outputs found
A Situation-Aware Collision Avoidance Strategy for Car-Following
In this paper, we discuss how to develop an appropriate collision avoidance strategy for car-following. This strategy aims to keep a good balance between traffic safety and efficiency while also taking into consideration the unavoidable uncertainty of position/speed perception/measurement of vehicles and other drivers. Both theoretical analysis and numerical testing results are provided to show the effectiveness of the proposed strategy
Far-Field Tunable Nano-focusing Based on Metallic Slits Surrounded with Nonlinear-Variant Widths and Linear-Variant Depths of Circular Dielectric Grating
In this work, we design a new tunable nanofocusing lens by the linear-variant
depths and nonlinear-variant widths of circular grating for far field practical
applications. The constructively interference of cylindrical surface plasmon
launched by the subwavelength metallic structure can form a
subdiffraction-limited focus, and the focal length of the this structures can
be adjusted if the each groove depth and width of circular grating are arranged
in traced profile. According to the numerical calculation, the range of
focusing points shift is much more than other plasmonic lens, and the relative
phase of emitting light scattered by surface plasmon coupling circular grating
can be modulated by the nonlinear-variant width and linear-variant depth. The
simulation result indicates that the different relative phase of emitting light
lead to variant focal length. We firstly show a unique phenomenon for the
linear-variant depths and nonlinear-variant widths of circular grating that the
positive change and negative change of the depths and widths of grooves can
result in different of variation trend between relative phases and focal
lengths. These results paved the road for utilizing the plasmonic lens in
high-density optical storage, nanolithography, superresolution optical
microscopic imaging, optical trapping, and sensing.Comment: 14pages,9figure
Symmetry classes of dissipative topological insulators with edge dark state
We classify the dissipative topological insulators (TIs) with edge dark
states (EDS) by using the 38-fold way of non-Hermitian systems in this paper.
The dissipative dynamics of these quadratic open fermionic systems is captured
by a non-Hermitian single-particle matrix which contains both the internal
dynamics and the dissipation, refereed to as damping matrix . And the dark
states in these systems are the eigenmodes of which the eigenvalues'
imaginary part vanishes. However, there is a constraint on , namely that the
modes in which the eigenvalues' imaginary parts are positive are forbidden. In
other words, the imaginary line-gap of is ill-defined, so the topological
band theory classifying the dark states can not be applied to . To reveal
the topological protection of EDS, we propose the double damping matrix
, where the imaginary line-gap is
well defined. Thus, the 38-fold way can be applied to , and the
topological protection of the EDS is uncovered. Different from previous studies
of EDS in purely dissipative dynamics, the EDS in the dissipative TIs are
robust against the inclusion of Hamiltonians. Furthermore, the topological
classification of not only reflects the topological protection of
EDS in dissipative TIs but also provides a paradigm to predict the appearance
of EDS in other open free fermionic systems.Comment: 8 pages, 4 figure
Downregulation of CD147 expression alters cytoskeleton architecture and inhibits gelatinase production and SAPK pathway in human hepatocellular carcinoma cells
<p>Abstract</p> <p>Background</p> <p>CD147 plays a critical role in the invasive and metastatic activity of hepatocellular carcinoma (HCC) cells by stimulating the surrounding fibroblasts to express matrix metalloproteinases (MMPs). Tumor cells adhesion to extracellular matrix (ECM) proteins is the first step to the tumor metastasis. MMPs degrade the ECM to promote tumor metastasis. The aim of this study is to investigate the effects of small interfering RNA (siRNA) against CD147 (si-CD147) on hepatocellular carcinoma cells' (SMMC-7721) architecture and functions.</p> <p>Methods</p> <p>Flow cytometry and western blot assays were employed to detect the transfection efficiency of si-CD147. Confocal microscopy was used to determine the effects of si-CD147 on SMMC-7721 cells' cytoskeleton. Invasion assay, gelatin zymography and cell adhesion assay were employed to investigate the effects of si-CD147 on SMMC-7721 cells' invasion, gelatinase production and cell adhesive abilities. Western blot assay was utilized to detect the effects of si-CD147 on focal adhesion kinase (FAK), vinculiln and mitogen-activated protein kinase (MAPK) expression in SMMC-7721 cells.</p> <p>Results</p> <p>Downregulation of CD147 gene induced the alteration of SMMC-7721 cell cytoskeleton including actin, microtubule and vimentin filaments, and inhibited gelatinase production and expression, cells invasion, FAK and vinculin expression. si-CD147 also blocked SMMC-7721 cells adhesion to collagen IV and phosphorylation level of SAPK/JNKs. SAPK/JNKs inhibitor SP600125 inhibited gelatinase production and expression.</p> <p>Conclusion</p> <p>CD147 is required for normal tumor cell architecture and cell invasion. Downregulation of CD147 affects HCC cell structure and function. Moreover, the alteration of cell behavior may be related to SAPK/JNK Pathway. siRNA against CD147 may be a possible new approach for HCC gene therapy.</p
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