In this paper, we analyze the long-time behavior of the solution of the initial value problem (IVP) for the short pulse (SP) equation. As the SP equation is a completely integrable system, which ...posses a Wadati–Konno–Ichikawa (WKI)-type Lax pair, we formulate a 2×2 matrix Riemann–Hilbert problem to this IVP by using the inverse scattering method. Since the spectral variable k is the same order in the WKI-type Lax pair, we construct the solution of this IVP parametrically in the new scale (y,t), whereas the original scale (x,t) is given in terms of functions in the new scale, in terms of the solution of this Riemann–Hilbert problem. However, by employing the nonlinear steepest descent method of Deift and Zhou for oscillatory Riemann–Hilbert problems, we can get the explicit leading order asymptotic of the solution of the short pulse equation in the original scale (x,t) as time t goes to infinity.
Great progress has been made in inorganic persistent phosphors, especially in the recent two decades, motivated by the discoveries of the SrAl2O4:Eu2+-Dy3+ in the green and Cr3+ doped spinel ...compounds in the deep-red to near-infrared (NIR) spectral regions. However, the physical mechanism behind this kind of “self-sustained” luminescence is still the subject of debate, and the improvement of known persistent phosphors and/or the development of new ones are still a matter of trial-and-error. In this review, starting from the introduction of longstanding histories of persistent luminescence (PersL), we provide comprehensive insights into its physical mechanism. Particular focus is put on the state-of-the-art of designing new persistent phosphors via “bandgap engineering”, based on the knowledge about trapping-detrapping mechanisms of charge carriers and energy level locations of emitting/trapping centers. Recent significant works on PersL observed in organic molecules and phosphorescence observed in inorganic phosphors are also highlighted in order to give a clear distinction between these two long-lived luminescence phenomena. Key challenges, feasible improvements and perspectives of PersL working in the ultraviolent (UV), white, red and NIR (over 1000 nm) regions together with new charging concepts by NIR or visible-light lasers are also presented. It is hoped that this review could give new inspiration for the future development of PersL in emerging applications.
Multifunctional antibacterial photodynamic therapy is a promising method to combat regular and multidrug‐resistant bacteria. In this work, eosin Y (EY)‐based antibacterial polycations (EY‐QEGEDR, R ...= CH3 or C6H13) with versatile types of functional components including quaternary ammonium, photosensitizer, primary amine, and hydroxyl species are readily synthesized based on simple ring‐opening reactions. In the presence of light irradiation, such antibacterial polymers exhibit high antibacterial efficiency against both Escherichia coli and Staphylococcus aureus. In particular, EY‐QEGEDR elicits a remarkable synergistic antibacterial activity owing to the combined photodynamic and quaternary ammonium antibacterial effects. Due to its rich primary amine groups, EY‐QEGEDR also can be readily coated on different substrates, such as glass slides and nonwoven fabrics via an adhesive layer of polydopamine. The resultant surface coating of EY‐QEGEDCH3 (s‐EY‐QEGEDCH3) produces excellent in vitro antibacterial efficacy. The plentiful hydroxyl groups impart s‐EY‐QEGEDCH3 with potential antifouling capability against dead bacteria. The antibacterial polymer coatings also demonstrate low cytotoxicity and good hemocompatibility. More importantly, s‐EY‐QEGEDCH3 significantly enhances in vivo therapeutic effects on an infected rat model. The present work provides an efficient strategy for the rational design of high‐performance antibacterial materials to fight biomedical device‐associated infections.
Polycationic synergistic antibacterial agents with versatile functional components including quaternary ammonium, photosensitizer, primary amine, and hydroxyl species are proposed for effective biomedical applications.
The human society is faced with daunting threats from bacterial infections. Over decades, a variety of antibacterial polymeric nanosystems have exhibited great promise for the eradication of ...multidrug‐resistant bacteria and persistent biofilms by enhancing bacterial recognition and binding capabilities. In this Review, the “state‐of‐the‐art” biodegradable antibacterial polymeric nanosystems, which could respond to bacteria environments (e.g., acidity or bacterial enzymes) for controlled antibiotic release or multimodal antibacterial treatment, are summarized. The current antibacterial polymeric nanosystems can be categorized into antibiotic‐containing and intrinsic antibacterial nanosystems. The antibiotic‐containing polymeric nanosystems include antibiotic‐encapsulated nanocarriers (e.g., polymeric micelles, vesicles, nanogels) and antibiotic‐conjugated polymer nanosystems for the delivery of antibiotic drugs. On the other hand, the intrinsic antibacterial polymer nanosystems containing bactericidal moieties such as quaternary ammonium groups, phosphonium groups, polycations, antimicrobial peptides (AMPs), and their synthetic mimics, are also described. The biodegradability of the nanosystems can be rendered by the incorporation of labile chemical linkages, such as carbonate, ester, amide, and phosphoester bonds. The design and synthesis of the degradable polymeric building blocks and their fabrications into nanosystems are also explicated, together with their plausible action mechanisms and potential biomedical applications. The perspectives of the current research in this field are also described.
Here, the recent advances in the field of biodegradable antibacterial polymeric nanosystems, including antibiotic‐containing polymeric nanosystems and intrinsic antibacterial polymer nanosystems in the forms of micelles, vesicles, nanogels, hyperbranched nanoclusters, and antibacterial polymer nanoparticles, are summarized for enhanced recognition and eradication capabilities against pathogenic bacteria.
SARS-CoV-2 infection is an initial factor to cause host damage. ...it is speculated that the damage of early patients is mainly related to the direct attack of the virus on the host, antiviral ...therapy early might be a useful strategy for preventing disease from progressing into severe or critical cases. Non-steroidal anti-inflammatory drugs (NSAIDs) and glucocorticoids seem to be a valuable therapeutic strategy for anti-inflammatory to reduce severe COVID-19-related illness in the outpatient stage of COVID-19. ...as shown in Fig. 1, we recommend “bi-anti” (antiviral and anti-inflammatory simultaneously) therapy in an outpatient setting at the early stages of SARS‐CoV‐2 infection. SEE PDF Overall, SARS-CoV-2 infection is only the initiating factor of the COVID-19, and the host’s immune response induced by SARS-CoV-2 is the key factor resulting in the disease progression. ...we propose the concept of “bi-anti” at the mild/moderate stage of SARS-CoV-2 infection to prevent the COVID-19 from developing into severe or critical disease.
Owing to the growing heat removal issue in modern electronic devices, electrically insulating polymer composites with high thermal conductivity have drawn much attention during the past decade. ...However, the conventional method to improve through‐plane thermal conductivity of these polymer composites usually yields an undesired value (below 3.0 Wm−1 K−1). Here, construction of a 3D phonon skeleton is reported composed of stacked boron nitride (BN) platelets reinforced with reduced graphene oxide (rGO) for epoxy composites by the combination of ice‐templated and infiltrating methods. At a low filler loading of 13.16 vol%, the resulting 3D BN‐rGO/epoxy composites exhibit an ultrahigh through‐plane thermal conductivity of 5.05 Wm−1 K−1 as the best thermal‐conduction performance reported so far for BN sheet‐based composites. Theoretical models qualitatively demonstrate that this enhancement results from the formation of phonon‐matching 3D BN‐rGO networks, leading to high rates of phonon transport. The strong potential application for thermal management has been demonstrated by the surface temperature variations of the composites with time during heating and cooling.
An oriented phonon‐matching skeleton is developed based on two kinds of 2D materials for efficient thermal conduction in polymer composites via ice‐templated assembly technology. This development leads to significantly improved through‐plane thermal conductivity for polymer composites when compared with traditional strategies, suggesting strong potential in thermal management. The results would benefit the design of novel thermal‐management materials.
...a well-designed TB screening strategy involving the government, medical institutions and society is difficult to realize. ...the detection and diagnosis of TB is relatively insufficient in China. ...Finding a universal TB screening strategy is a top priority for TB control in China. Since the end of 2019, COVID-19 has caused profound economic and social disruption worldwide, and countries have adopted different prevention and control strategies.
AIM To investigate the clinical significance of preoperative systemic immune-inflammation index(SII) in patients with colorectal cancer(CRC). METHODS A retrospective analysis of 1383 cases with CRC ...was performed following radical surgery. SII was calculated with the formula SII =(P × N)/L, where P, N, and L refer to peripheral platelet, neutrophil, and lymphocyte counts, respectively. The clinicopathological features and follow-up data were evaluated to compare SII with other systemic inflammation-based prognostic indices such as the neutrophil-lymphocyte ratio(NLR) and platelet-lymphocyte ratio(PLR) in patients with CRC.RESULTS The optimal cut-off point for SII was defined as 340. The overall survival(OS) and disease-free survival(DFS) were better in patients with low NLR, PLR, and SII(P < 0.05). The SII was an independent predictor of OS and DFS in multivariate analysis. The area under the receiver-operating characteristics(ROC) curve for SII(0.707) was larger than those for NLR(0.602) and PLR(0.566). In contrast to NLR and PLR, SII could effectively discriminate between the TNM subgroups. CONCLUSION SII is a more powerful tool for predicting survival outcome in patients with CRC. It might assist the identification of high-risk patients among patients with the same TNM stage.
Efficient antimicrobials are urgently needed for the treatment of bacterial biofilms due to their resistance to traditional drugs. Photodynamic therapy (PDT) is a new strategy that has been used to ...combat bacteria and biofilms. Cationic photosensitizers, particularly cationic photodynamic nanoagents, are usually chosen to enhance photodynamic antimicrobial activity. However, positively charged nanoparticles (NPs) are beneficial to cellular internalization, which causes increased cell cytotoxicity. Herein, a pH‐sensitive photodynamic nanosystem is designed. Rose Bengal (RB) polydopamine (PDA) NPs are decorated in a layer‐by‐layer fashion with polymyxin B (PMB) and gluconic acid (GA) to generate functionally adaptive NPs (RB@PMB@GA NPs). RB@PMB@GA NPs remain negative at physiological pH and exhibit good biocompatibility. When RB@PMB@GA NPs are exposed to an acidic infectious environment, the surface charge of the NPs is, in turn, positively charged as a result of pH‐sensitive electrostatic interactions. This surface charge conversion allows the RB@PMB@GA to effectively bind to the surfaces of bacteria and enhance photoinactivation efficiency against gram‐negative bacteria. Most importantly, RB@PMB@GA NPs exhibit good biofilm penetration and eradication under acidic conditions. Furthermore, RB@PMB@GA NPs efficiently eliminate biofilm infections in vivo. This study provides a promising strategy for safely treating biofilm‐associated infections in vivo.
A pH‐sensitive photodynamic nanosystem is proposed. RB@PMB@GA nanoparticles (NPs) remain negatively charged at physiological pH and convert to be positively charged NPs in an acidic infectious environment. The conversion of the surface charge allows the NPs to effectively bind to the surfaces of negatively charged bacteria and significantly enhance their penetration and antibacterial photodynamic efficiency in biofilms of gram‐negative bacteria.
Exploring new type of synapse–like electronic devices with fusion of computing and memory is a promising strategy to fundamentally approach to intelligent machines. Herein, organic thin film ...memristors (OTFMs) are achieved, functioning as electrically programmable and erasable analog memory with continuous and nonvolatile device states. The memristive characteristics of OTFMs stem from the asymmetric electrode configuration and the cumulative charge trapping/detrapping in a polymer electret layer, which enables the state–dependent current modulation analogous to the synaptic weight change in biological synapses. OTFMs are demonstrated to successfully emulate the essential synaptic functions, including the reversible potentiation and depression, and the short‐term plasticity such as the paired‐pulse facilitation and the long‐term plasticity such as the spike–timing dependent plasticity.
Organic thin film memristors are achieved based on asymmetric electrode configuration and cumulative charge trapping/detrapping in a polymer electret layer, which function as electrically editable and preservable analog memory. Organic thin film memristors are demonstrated to be capable of emulating both short‐term and long‐term synaptic plasticity, such as the paired‐pulse facilitation and spike‐timing‐dependent plasticity.
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