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31.
32.
Wanhe Wang Ke‐Jia Wu Kasipandi Vellaisamy Chung‐Hang Leung Dik‐Lung Ma 《Angewandte Chemie (International ed. in English)》2020,59(41):17897-17902
Gastrin‐releasing peptide receptor (GRPr) plays proliferative and inflammatory roles in living systems. Here, we report a highly selective GRPr antagonist (JMV594)‐tethered iridium(III) complex for probing GRPr in living cancer cells and immune cells. This probe exhibited desirable photophysical properties and also displayed negligible cytotoxicity, overcoming the inherent toxicity of the iridium(III) complex. Its long emission lifetime enabled its luminescence signal to be readily distinguished from the interfering fluorescence of organic dyes by using a time‐resolved technique. This probe selectively visualized living cancer cells via specific binding to GRPr, while it also modulated the function of GRPr on TNF‐α secretion in immune cells. To our knowledge, this is the first peptide‐conjugated iridium(III) complex developed as a GRPr bioimaging probe and modulator of GRPr activity. This theranostic agent shows great potential at unmasking the diverse roles of GRPr in living systems. 相似文献
33.
Dr. Ming-Yu Wu Jong-Kai Leung Li Liu Dr. Chuen Kam Dr. Kelvin Yuen Kwong Chan Prof. Dr. Ronald A. Li Prof. Dr. Shun Feng Dr. Sijie Chen 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(26):10413-10417
The chromosome periphery (CP) is a complex network that covers the outer surface of chromosomes. It acts as a carrier of nucleolar components, helps maintain chromosome structure, and plays an important role in mitosis. Current methods for fluorescence imaging of CP largely rely on immunostaining. We herein report a small-molecule fluorescent probe, ID-IQ , which possesses aggregation-induced emission (AIE) property, for CP imaging. By labelling the CP, ID-IQ sharply highlighted the chromosome boundaries, which enabled rapid segmentation of touching and overlapping chromosomes, direct identification of the centromere, and clear visualization of chromosome morphology. ID-IQ staining was also compatible with fluorescence in situ hybridization and could assist the precise location of the gene in designated chromosome. Altogether, this study provides a versatile cytogenetic tool for improved chromosome analysis, which greatly benefits the clinical diagnostic testing and genomic research. 相似文献
34.
In this paper, a powerfully analytical technique is proposed for predicting and generating the steady state solution of the fractional differential system based on the method of harmonic balance. The zeroth-order approximation using just one Fourier term is applied to predict the parametric function for the boundary between oscillatory and non-oscillatory regions of the fractional van der Pol oscillator. The unbalanced residues due to Fourier truncation are considered iteratively by solving linear algebraic equations to improve the accuracy of the solutions successively. The highly accurate solutions to the angular frequency and limit cycle of fractional van der Pol oscillator are obtained and compared. The results reveal that the technique described in this paper is very effective and simple for obtaining asymptotic solution of nonlinear system having fractional order derivative. 相似文献
35.
Shingyu Leung 《Journal of computational physics》2011,230(9):3500-3524
We propose efficient Eulerian methods for approximating the finite-time Lyapunov exponent (FTLE). The idea is to compute the related flow map using the Level Set Method and the Liouville equation. There are several advantages of the proposed approach. Unlike the usual Lagrangian-type computations, the resulting method requires the velocity field defined only at discrete locations. No interpolation of the velocity field is needed. Also, the method automatically stops a particle trajectory in the case when the ray hits the boundary of the computational domain. The computational complexity of the algorithm is O(Δx?(d+1)) with d the dimension of the physical space. Since there are the same number of mesh points in the x–t space, the computational complexity of the proposed Eulerian approach is optimal in the sense that each grid point is visited for only O(1) time. We also extend the algorithm to compute the FTLE on a co-dimension one manifold. The resulting algorithm does not require computation on any local coordinate system and is simple to implement even for an evolving manifold. 相似文献
36.
We develop numerical methods for solving partial differential equations (PDE) defined on an evolving interface represented by the grid based particle method (GBPM) recently proposed in [S. Leung, H.K. Zhao, A grid based particle method for moving interface problems, J. Comput. Phys. 228 (2009) 7706–7728]. In particular, we develop implicit time discretization methods for the advection–diffusion equation where the time step is restricted solely by the advection part of the equation. We also generalize the GBPM to solve high order geometrical flows including surface diffusion and Willmore-type flows. The resulting algorithm can be easily implemented since the method is based on meshless particles quasi-uniformly sampled on the interface. Furthermore, without any computational mesh or triangulation defined on the interface, we do not require remeshing or reparametrization in the case of highly distorted motion or when there are topological changes. As an interesting application, we study locally inextensible flows governed by energy minimization. We introduce tension force via a Lagrange multiplier determined by the solution to a Helmholtz equation defined on the evolving interface. Extensive numerical examples are also given to demonstrate the efficiency of the proposed approach. 相似文献
37.
Current–voltage (J–V) characteristics of epitaxial hetero-junctions composed of Pr0.7Ca0.3MnO3 and Nb:SrTiO3 were studied under forward and reversed bias conditions. Detailed analysis showed that the J–V characteristics of these heterojunctions can be well-fitted by the thermally-assisted tunnelling model. While the dielectric constant of Nb:SrTiO3 extracted under the forward bias was about one order of magnitude smaller than that of bulk SrTiO3, the value obtained under reverse bias was very close to that of the bulk SrTiO3. The result can be explained by the existence of an interface layer on the Nb:SrTiO3 substrate with a smaller effective dielectric constant. The current finding suggested that the properties of interface layer should be taken into account in order to accurately simulate the J–V characteristics of such heterojunctions. 相似文献
38.
D. M. H. Leung B. M. A. Rahman N. Kejalakshmy K. T. V. Grattan 《Optical and Quantum Electronics》2011,42(8):499-509
The Poynting vector and the full-vectorial H and E-field profiles are considered for use in nanoscale silicon waveguides in this article. This paper reveals that the mode profile
of a circular silicon nanowire is not circular and also has a strong axial field component. From the analysis, the characteristics
of single mode operation and the vector field profiles of both circular and planar silicon nanowires are presented. The modal
birefringence of rectangular silicon nanowires and power density in low-index region of a slot-type waveguide and designs
of a compact polarization rotator are also presented in this work. 相似文献
39.
Pheophorbide a (PhA) was identified as a photosensitizer to exert cytotoxicity on tumor cells. However, the efficacy of this
compound on the treatment of prostate cancer remains unknown. The aim of this study was to evaluate the photodynamic effect
of PhA on prostate cancer cells. Cellular uptake of PhA and cell viability after photo-activation was studied in LNCaP prostate
cancer cells. The corresponding production of reactive oxygen species within cells was determined after photodynamic therapy
(PDT). Our results showed that the uptake of PhA into LNCaP cells was in a time-dependent manner and the cytotoxicity of PhA-PDT
was photosensitizer dose- and light dose-dependent. The intracellular reactive oxygen species was remarkably induced after
PDT treatment, which was responsible for the inhibition effect on prostate cancer cells. This is the first report to evaluate
the photodynamic effect of PhA on prostate cancer. Our findings demonstrate that PhA-PDT may be a potentially promising treatment
for localized prostate cancer, which can be a therapeutic option after the failures of radiotherapy and hormone therapy. 相似文献