204 research outputs found

    Pullback Attractor for Nonautonomous Ginzburg-Landau Equation with Additive Noise

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    Long time behavior of stochastic Ginzburg-Landau equations with nonautonomous deterministic external forces, dispersion coefficients, and nonautonomous perturbations is studied. The domain is taken as a bounded interval I in R. By making use of Sobolev embeddings and Gialiardo-Nirenberg inequality we obtain the existence and upper semicontinuity of the pullback attractor in L2(I) for the equation. The upper semicontinuity shows the stability of attractors under perturbations

    Regularity and structure of pullback attractors for reaction-diffusion type systems without uniqueness

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    In this paper, we study the pullback attractor for a general reaction-diffusion system for which the uniqueness of solutions is not assumed. We first establish some general results for a multi-valued dynamical system to have a bi-spatial pullback attractor, and then we find that the attractor can be backwards compact and composed of all the backwards bounded complete trajectories. As an application, a general reaction-diffusion system is proved to have an invariant (H, V )-pullback attractor A = {A(τ)}τ∈R. This attractor is composed of all the backwards compact complete trajectories of the system, pullback attracts bounded subsets of H in the topology of V, and moreover ∪ s6τ A(s) is precompact in V, ∀τ ∈ R. A non-autonomous Fitz-Hugh-Nagumo equation is studied as a specific example of the reaction–diffusion system.State Scholarship Fund (China)Junta de AndalucíaBrazilian-European partnership in Dynamical SystemsEuropean UnionNational Natural Science Foundation of Chin

    Implementation of elastic prestack reverse-time migration using an efficient finite-difference scheme

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    Elastic reverse-time migration (RTM) can reflect the underground elastic information more comprehensively than single-component P-wave migration. One of the most important requirements of elastic RTM is to solve wave equations. The imaging accuracy and efficiency of RTM depends heavily on the algorithms used for solving wave equations. In this paper, we propose an efficient staggered-grid finite-difference (SFD) scheme based on a sampling approximation method with adaptive variable difference operator lengths to implement elastic prestack RTM. Numerical dispersion analysis and wavefield extrapolation results show that the sampling approximation SFD scheme has greater accuracy than the conventional Taylor-series expansion SFD scheme. We also test the elastic RTM algorithm on theoretical models and a field data set, respectively. Experiments presented demonstrate that elastic RTM using the proposed SFD scheme can generate better images than that using the Taylor-series expansion SFD scheme, particularly for PS images. Furthermore, the application of adaptive variable difference operator lengths can effectively improve the computational efficiency of elastic RTM

    Dimensional Adjectives in Nuosu Yi

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    In this paper, we discuss two types of dimensional adjectives in Nuosu Yi (Tibeto- Burman), which we refer to as Positive adjectives (PAs) and Equative Adjectives (EAs). We show that PAs and EAs are subject to different distributions in gradation structures: EAs are only admissible in gradation structures that can be associated with measure phrases, which include differential comparatives (e.g., Ayi is 2 cm taller than Aguo. ) and degree questions (e.g., How tall is Ayi ?). PAs are licensed elsewhere, including comparatives that do not introduce a differential (e.g., Ayi is taller than Aguo. ), the intensification construction (e.g., Ayi is very tall ), the superlative construction (e.g., Ayi is the tallest ), etc. Assuming that measure phrases are degree-denoting expressions, we propose that the complimentary distribution of PAs and EAs in Nuosu Yi is due to their different semantics

    Multifunctional targeting micelle nanocarriers with both imaging and therapeutic potential for bladder cancer.

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    BackgroundWe previously developed a bladder cancer-specific ligand (PLZ4) that can specifically bind to both human and dog bladder cancer cells in vitro and in vivo. We have also developed a micelle nanocarrier drug-delivery system. Here, we assessed whether the targeting micelles decorated with PLZ4 on the surface could specifically target dog bladder cancer cells.Materials and methodsMicelle-building monomers (ie, telodendrimers) were synthesized through conjugation of polyethylene glycol with a cholic acid cluster at one end and PLZ4 at the other, which then self-assembled in an aqueous solution to form micelles. Dog bladder cancer cell lines were used for in vitro and in vivo drug delivery studies.ResultsCompared to nontargeting micelles, targeting PLZ4 micelles (23.2 ± 8.1 nm in diameter) loaded with the imaging agent DiD and the chemotherapeutic drug paclitaxel or daunorubicin were more efficient in targeted drug delivery and more effective in cell killing in vitro. PLZ4 facilitated the uptake of micelles together with the cargo load into the target cells. We also developed an orthotopic invasive dog bladder cancer xenograft model in mice. In vivo studies with this model showed the targeting micelles were more efficient in targeted drug delivery than the free dye (14.3×; P < 0.01) and nontargeting micelles (1.5×; P < 0.05).ConclusionTargeting micelles decorated with PLZ4 can selectively target dog bladder cancer cells and potentially be developed as imaging and therapeutic agents in a clinical setting. Preclinical studies of targeting micelles can be performed in dogs with spontaneous bladder cancer before proceeding with studies using human patients

    Novel insights into circular RNAs in clinical application of carcinomas

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    Circular RNAs (circRNAs), formed by nonsequential back-splicing of pre-messenger RNA (pre-mRNA) transcripts, have been widely concerned in recent years. With advances in high-throughput RNA sequencing (RNA-seq) technology, previous work has revealed that a large number of circRNAs, which are endogenous, abundant and stable in mammalian cells, may be involved in atherosclerotic vascular disease risk, neurological disorders, prion diseases and carcinomas. Remarkably, interaction between circRNAs and microRNA has already been observed to perform a significant role in a variety of cancers, including gastric cancer and colorectal cancer. Recent work has suggested that circRNAs may play critical roles in the initiation and development of cancers and could become potential new biomarkers for cancers. Herein, we review the current understanding of the roles of circRNAs in cancers and the potential implications of circRNAs in cancer-targeted therapy

    Role of Small Molecule Targeted Compounds in Cancer: Progress, Opportunities, and Challenges

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    Research on molecular targeted therapy of tumors is booming, and novel targeted therapy drugs are constantly emerging. Small molecule targeted compounds, novel targeted therapy drugs, can be administered orally as tablets among other methods, and do not draw upon genes, causing no immune response. It is easily structurally modified to make it more applicable to clinical needs, and convenient to promote due to low cost. It refers to a hotspot in the research of tumor molecular targeted therapy. In the present study, we review the current Food and Drug Administration (FDA)-approved use of small molecule targeted compounds in tumors, summarize the clinical drug resistance problems and mechanisms facing the use of small molecule targeted compounds, and predict the future directions of the evolving field

    An early warning method for a slope based on the increment ratio of anchor cable internal force

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    Prestressed anchor cables are active reinforcement to improve slope stability. However, the anchoring is not a permanent guarantee of stability, and the slope retains a potential risk of instability. From the perspective of the internal force of anchor cables, a new early warning method for the safety of the slope is provided, and a slope analysis model is established. With the increase in the strength reduction factor, the internal force increment curves of anchor cables under different prestresses are obtained. The point corresponding to strength reduction factors λ1 and λ2 represents a warning point. Key conclusions are drawn as follows: (1) The internal force of an anchor cable can be used to judge the stability of the slope strengthened by a prestressed anchor cable. (2) A warning index based on the internal force increment ratio of anchor cables is established. (3) The internal force increment ratio of anchor cables eliminates the influence of the initial prestress and is convenient for engineering applications
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