Study of Metallic Nano-Optic Structures

Physical phenomena (optical, electronic and optoelectronic) occurring in metallic nanostructures offer an interesting potential in that they may allow us to overcome the limits of diffractive optics and to develop new functional devices complementing the dielectric-based conventional optics. Optical waves incident to a metallic structure, for example, can excite a collective oscillation of electrons, so-called surface plasmons (SPs). The spatial extension of SP fields is governed by the size of the nanostructure and can be made much smaller than the wavelength of light. These features are potentially useful in developing ultracompact photonic chips, i.e., miniaturizing the optics into subwavelength dimensions.In this thesis, we have investigated the plasmonic phenomena occurring in metallic nanoaperture array structures. A novel fabrication process has been developed to form highly ordered nanoaperture (both slits and holes) arrays on metallic layers. Optical characterization of the fabricated nanostructures revealed many interesting properties (in transmission, reflection, filtering, confinement, etc.) involving plasmonic interactions. The plasmonic phenomena in nanoaperture arrays have been analyzed theoretically: analytical solutions of plasmonic waveguiding inside nanoslits were formulated; funneling of light into nanoslit was simulated; the in-plane surface plasmon band structures at the metal/dielectric interfaces were modeled; the dynamic evolution of polarization in metal islands was analyzed. The finite-difference time-domain (FDTD) analysis of optical field distribution and propagation has been performed, and the simulation results were compared with the analytic results and experimental data. Detailed mechanisms of the plasmonic interactions in nanoaperture arrays have been developed and proposed based on this experimental and theoretical study.We further studied optical transmission properties of bi-layer metallic nanoslit arrays. The structure is found to reveal Fabry-Perot-resonator-like characteristics and the transmittance, passband, and beam polarization properties are determined by structure, dimension, and configuration. Near-field interaction and coupling in the bi-layer slit array structures were also analyzed with FDTD simulation. We also studied surface plasmon effects in reflective metallic grating structures, which show strong reflection quenching under cross-metal SP coupling conditions. We have designed and analyzed metallic nano-optic lenses based on nanoslit array structures. The phase of optical radiation emanating from each aperture is controlled by the metal thickness and aperture size. FDTD simulation of the nano-optic lenses demonstrates refractive transmission of light and beam shaping (focusing and collimation). This study opens up the possibility of developing a new class of optics that can complement the conventional dielectric-based refractive/diffractive optics

The semi-discrete AKNS system: Conservation laws, reductions and continuum limits

In this paper, the semi-discrete Ablowitz-Kaup-Newell-Segur (AKNS) hierarchy is shown in spirit composed by the Ablowitz-Ladik flows under certain combinations. Furthermore, we derive its explicit Lax pairs and infinitely many conservation laws, which are non-trivial in light of continuum limit. Reductions of the semi-discrete AKNS hierarchy are investigated to include the semi-discrete Korteweg-de Vries (KdV), the semi-discrete modified KdV, and the semi-discrete nonlinear Schr\"odinger hierarchies as its special cases. Finally, under the uniform continuum limit we introduce in the paper, the above results of the semi-discrete AKNS hierarchy, including Lax pairs, infinitely many conservation laws and reductions, recover their counterparts of the continuous AKNS hierarchy

Mixed Arlequin method for multiscale poromechanics problems

An Arlequin poromechanics model is introduced to simulate the hydro-mechanical coupling effects of fluid-infiltrated porous media across different spatial scales within a concurrent computational framework. A two-field poromechanics problem is first recast as the twofold saddle point of an incremental energy functional. We then introduce Lagrange multipliers and compatibility energy functionals to enforce the weak compatibility of hydro-mechanical responses in the overlapped domain. To examine the numerical stability of this hydro-mechanical Arlequin model, we derive a necessary condition for stability, the twofold inf–sup condition for multi-field problems, and establish a modified inf–sup test formulated in the product space of the solution field. We verify the implementation of the Arlequin poromechanics model through benchmark problems covering the entire range of drainage conditions. Through these numerical examples, we demonstrate the performance, robustness, and numerical stability of the Arlequin poromechanics model

Effects of ulinastatin and docataxel on breast tumor growth and expression of IL-6, IL-8, and TNF-α

<p>Abstract</p> <p>Objective</p> <p>This study investigated the effects of Ulinastatin (UTI) and docataxel (Taxotere, TAX) on tumor growth and expression of interleukin-6 (IL-6), interleukin-8 (IL-8), and tumor necrosis factor-α (TNF-α) in breast cancer.</p> <p>Methods</p> <p>MDA-MB-231 human breast carcinoma cells were cultured in vitro and injected into nude mice to establish breast tumor xenografts in vivo. Cultured cells and mice with tumors were randomly divided into four groups for treatment with TAX, UTI, and TAX+UTI. The effects of these drug treatments on cell proliferation and apoptosis was measured using the MTT assay and the Annexin V/propidium iodide (PI) double-staining method, respectively. IL-6, IL-8, and TNF-α expression levels were determined by measuring mRNA transcripts in cultured cells by RT-PCR and cytokine proteins in solid tumors using immunohistochemistry.</p> <p>Results</p> <p>UTI, TAX, and UTI+TAX inhibited the growth of MDA-MB-231 cells in vitro and tumors in vivo. These two drugs, particularly when used in combination, promote tumor cell apoptosis and down-regulate the expression IL-6, IL-8, and TNF-α cytokines.</p> <p>Conclusion</p> <p>Both UTI and TAX inhibited the growth of MDA-MB-231 breast carcinoma cells. UTI enhanced the inhibitory effect of TAX by a mechanism consistent with the down-regulated expression of IL-6, IL-8, and TNF-α.</p

Learning from Noisy Crowd Labels with Logics

This paper explores the integration of symbolic logic knowledge into deep neural networks for learning from noisy crowd labels. We introduce Logic-guided Learning from Noisy Crowd Labels (Logic-LNCL), an EM-alike iterative logic knowledge distillation framework that learns from both noisy labeled data and logic rules of interest. Unlike traditional EM methods, our framework contains a ``pseudo-E-step'' that distills from the logic rules a new type of learning target, which is then used in the ``pseudo-M-step'' for training the classifier. Extensive evaluations on two real-world datasets for text sentiment classification and named entity recognition demonstrate that the proposed framework improves the state-of-the-art and provides a new solution to learning from noisy crowd labels.Comment: 12 pages, 7 figures, accepted by ICDE-202

Dynamic Behavior Analysis and Synchronization of Memristor-Coupled Heterogeneous Discrete Neural Networks

© 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).Continuous memristors have been widely studied in recent years; however, there are few studies on discrete memristors in the field of neural networks. In this paper, a four-stable locally active discrete memristor (LADM) is proposed as a synapse, which is used to connect a two-dimensional Chialvo neuron and a three-dimensional KTZ neuron, and construct a simple heterogeneous discrete neural network (HDNN). Through a bifurcation diagram and Lyapunov exponents diagram, the period and chaotic regions of the discrete neural network model are shown. Through numerical analysis, it was found that the chaotic region and periodic region of the neural network based on DLAM are significantly improved. In addition, coexisting chaos and chaos attractors, coexisting periodic and chaotic attractors, and coexisting periodic and periodic attractors will appear when the initial value of the LADM is changed. Coupled by a LADM synapse, two heterogeneous discrete neurons are gradually synchronized by changing the coupling strength. This paper lays a good foundation for the future analysis of LADMs and the related research of discrete neural networks coupled by LADMs.Peer reviewe

Effect of ulinastatin on growth inhibition, apoptosis of breast carcinoma cells is related to a decrease in signal conduction of JNk-2 and NF-κB

<p>Abstract</p> <p>Objective</p> <p>This study aims to investigate the <it>in vitro </it>effects of Ulinastatin (UTI) and Taxotere (TXT) on cell proliferation; cell apoptosis; xenografted tumor growth; and expression of insulin-like growth factor receptor 1 (IGF-1R), platelet-derived growth factor A (PDGFA), nerve growth factor (NGF), c-Jun N-terminal kinase 2 (JNk-2), and NF-κB in a human primary breast cancer cells and breast cancer cell line MDA-MB-231.</p> <p>Methods</p> <p>The cell lines cultured were divided into four groups: 1) control group, 2) UTI group, 3) TXT group, and 4) UTI+TXT group. The method of MTT essay, flow cytometry, and RT-PCR were used to detect cell proliferation, cell apoptosis, and expression of IGF-1R, PDGFA, NGF, NF-κB, JNk-2, respectively. The growth of xenografted tumor in nude mice was used to calculate the anti-tumor rate. Immunohistochemistry staining (SP) was used to detect the expression of IGF-1R, PDGFA, NGF, ki-67, caspase-3, JNk-2, and NF-κB.</p> <p>Results</p> <p>Proliferation of human breast cancer cells and MDA-MB-231 cell lines, and growth rate of xenografted tumor decreased in order of UTI+TXT > TXT > UTI > control, apoptosis increased in the order control < UTI < TXT < UTI+TXT. The gene expression and protein expression of IGF-1R, PDGFA, NGF, NF-κB and JNk-2 in breast cancer cells was inhibited by UTI and TXT.</p> <p>Conclusions</p> <p>UTI 1) inhibits the proliferation of human breast cancer cells and the growth of xenografted tumors, 2) induces cancer cell apoptosis, and 3) enhances the anti-tumor effect of TXT. This mechanism might be related to decreasing signal transduction of JNk-2 and NF-κB, and then expression of IGF-1R, PDGFA, NGF.</p