Increased incidence of napkin-ring sign plaques on cervicocerebral computed tomography angiography associated with the risk of acute ischemic stroke occurrence.

OBJECTIVES: Carotid atherosclerosis plays an essential role in the occurrence of ischemic stroke. This study aimed to investigate whether a larger burden of napkin-ring sign (NRS) plaques on cervicocerebral computed tomography angiography (CTA) increased the risk of acute ischemic stroke (AIS). METHODS: This retrospective, single-center, cross-sectional study enrolled patients with NRS plaques identified in the subclavian arteries, brachiocephalic trunk, carotid arterial system, and vertebrobasilar circulation on contrast-enhanced cervicocerebral CTA. Patients were divided into AIS and non-AIS groups based on imaging within 12 h of symptom onset. Univariate and multivariate logistic regression analyses were performed to determine the risk factor of AIS occurrence. RESULTS: A total of 202 patients (66.72 years ± 8.97, 157 men) were evaluated. Plaques with NRS in each subject of the AIS group (N = 98) were significantly more prevalent than that in the control group (N = 104) (1.96 ± 1.17 vs 1.41 ± 0.62). In the AIS group, there were substantially more NRS plaques on the ipsilateral side than contralateral side (1.55 ± 0.90 vs. 0.41 ± 0.66). NRS located on the ipsilateral side of the AIS showed an area under the receiver curve (AUC) of 0.86 to identify ischemic stroke. NRS plaque amounts were an independent risk factor for AIS occurrence (odds ratio, 1.86) after adjusting for other factors. CONCLUSIONS: Increased incidence of napkin-ring sign plaques on cervicocerebral CTA was positively associated with AIS occurrence, which could aid in detecting asymptomatic atherosclerotic patients at high risk of AIS in routine screening or emergency settings. CLINICAL RELEVANCE STATEMENT: Napkin-ring sign plaque provides an important imaging target for estimating acute ischemic stroke risk and identifying high-risk patients in routine screening or emergency settings, so that timely anti-atherosclerotic therapy can be used for prevention. KEY POINTS: • This cross-sectional study investigated the association between high-risk carotid artery plaques and acute ischemic stroke. • Increased incidence of napkin-ring sign plaques on cervicocerebral computed tomography angiography is positively associated with acute ischemic stroke occurrence. • Napkin-ring signs help identify risky patients prone to acute ischemic stroke to facilitate prevention.

Effects of flow regimes on the interaction between granular flow and flexible barrier.

Flexible barriers are widely used to mitigate granular flows. In practice, flow regimes may keep changing along a flow path after the initiation of granular flows. The effects of flow regimes should be considered in the design of flexible barriers to intercept granular flow. In this study, flow regimes are divided into three types: dilute flow; dense flow; and quasistatic flow. The impact mechanisms of dense granular flows and dilute granular flows against flexible barriers are investigated using flume tests and the discrete element method. Influences of the ratio of the average particle size to the mesh size of a flexible barrier and particle segregation on the interaction between the flexible barrier and the granular flow are revealed. Differences of the impact mechanisms between rockfall and granular flow are compared. Results show that the impact force of dense granular flow against a flexible barrier will not increase linearly with the average particle size. The tensile force of the bottom cable is usually the maximum tensile force among all cables of the flexible barrier. Particle segregation will lead to increase in impact force of dense flows and tensile force of the upper cables. Impact force of the dilute granular flow increases with the average particle size. Different from the failure of a flexible barrier under the impact of the dense flow, the middle and upper cables are easier to break. Based on these findings, a useful reference for the future design of flexible barriers was proposed.

Does Trade Policy Uncertainty Exacerbate Environmental Pollution?-Evidence from Chinese Cities.

Although the relationship between trade and environment has been widely discussed in past studies, trade policy has been in a state of continuous change in recent years. Previous studies have focused on the impact of trade opening or liberalization on the environment, ignoring discussion of the dynamic changes of trade policy. Therefore, it is very important to explore the connection between trade policy changes and environmental pollution for future environmental protection. In order to realize the in-depth study of this mechanism, the paper will try to solve the following three problems: (1) What is the relationship between change in trade policy uncertainty and China's environmental pollution? (2) What is the mechanism by which trade uncertainty changes environmental pollution? (3) Due to China's vast territory and regional differences, will changes in trade policy uncertainty have heterogeneous effects due to regional differences? To solve these problems, based on China's accession to the WTO at the end of 2001, this paper, for the first time, uses PM2.5 concentration data of 246 prefecture-level cities in China to explore the impact of trade policy uncertainty on China's environmental pollution, then we make an in-depth analysis of the impact path and heterogeneity of urban spatial distribution and city size. We found that, after China's accession to the WTO, the growth rate of PM2.5 concentration reduced in cities with lower trade policy uncertainty and the inhibition effect was different due to the spatial distribution of city size. A further mechanism test shows that reduction in trade policy uncertainty can improve environmental pollution through industrial, structural and technological effects.

A New Class of Electronic Devices Based on Flexible Porous Substrates.

With the advent of the Internet of Things era, the connection between electronic devices and humans is getting closer and closer. New-concept electronic devices including e-skins, nanogenerators, brain-machine interfaces, and implantable medical devices, can work on or inside human bodies, calling for wearing comfort, super flexibility, biodegradability, and stability under complex deformations. However, conventional electronics based on metal and plastic substrates cannot effectively meet these new application requirements. Therefore, a series of advanced electronic devices based on flexible porous substrates (e.g., paper, fabric, electrospun nanofibers, wood, and elastic polymer sponge) is being developed to address these challenges by virtue of their superior biocompatibility, breathability, deformability, and robustness. The porous structure of these substrates can not only improve device performance but also enable new functions, but due to their wide variety, choosing the right porous substrate is crucial for preparing high-performance electronics for specific applications. Herein, the properties of different flexible porous substrates are summarized and their basic principles of design, manufacture, and use are highlighted. Subsequently, various functionalization methods of these porous substrates are briefly introduced and compared. Then, the latest advances in flexible porous substrate-based electronics are demonstrated. Finally, the remaining challenges and future directions are discussed.

Suppressing Corrosion of Aluminum Foils via Highly Conductive Graphene-like Carbon Coating in High-Performance Lithium-Based Batteries.

Aluminum foil is the predominant cathodic current collector in lithium-based batteries due to the high electronic conductivity, stable chemical/electrochemical properties, low density, and low cost. However, with the development of next-generation lithium batteries, Al current collectors face new challenges, such as the requirement of increased chemical stability at high voltage, long-cycle-life batteries with different electrolyte systems, as well as improved electronic conductivity and adhesion for new electrode materials. In this study, we demonstrate a novel graphene-like carbon (GLC) coating on the Al foil in lithium-based batteries. Various physical and electrochemical characterizations are conducted to reveal the electronic conductivity and electrochemical stability of the GLC-Al foil in both carbonate- and ether-based electrolytes. Full-cell tests, including Li-S batteries and high-voltage Li-ion batteries, are performed to demonstrate the significantly improved cycling and rate performance of batteries with the use of the GLC-Al foil as current collectors. The cell using the GLC-Al foil can greatly reduce the potential polarization in Li-S batteries and can obtain a reversible capacity of 750 mAh g-1 over 100 cycles at 0.5C. Even with high-sulfur-loading cathodes, the Li-S battery at 1C still maintains over 500 mAh g-1 after 100 cycles. In high-voltage Li-ion batteries, the GLC-Al foil significantly improves the high-rate performance, showing an increased retained capacity by over 100 mAh g-1 after 450 cycles at 1C compared to the bare foil. It is believed that the developed GLC-Al foil brings new opportunities to enhance the battery life of lithium-based batteries.

SU-8-Induced Strong Bonding of Polymer Ligands to Flexible Substrates via in Situ Cross-Linked Reaction for Improved Surface Metallization and Fast Fabrication of High-Quality Flexible Circuits.

On account of in situ cross-linked reaction of epoxy SU-8 with poly(4-vinylpyridine) (P4VP) and its strong reactive bonding ability with different pretreated substrates, we developed a simple universal one-step solution-based coating method for fast surface modification of various objects. Through this method, a layer of P4VP molecules with controllable thickness can be tethered tightly onto substrates with the assistance of SU-8. P4VP molecules possess a lot of pyridine ligands to immobilize transitional metal ions that can behave as the catalyst of electroless copper plating for surface metallization while functioning as the adhesion-promoting layer between the substrate and deposited metal. Attributed to interpenetrated entanglement of P4VP molecules and as-deposited metal, ultrathick (>7 µm) strongly adhesive high-quality copper layer can be formed on flexible substrates without any delamination. Then through laser printer to print toner mask, a variety of designed circuits can be easily fabricated on modified flexible PET substrate.

Direct Pen Writing of Adhesive Particle-Free Ultrahigh Silver Salt-Loaded Composite Ink for Stretchable Circuits.

In this article, we describe a writable particle-free ink for fast fabrication of highly conductive stretchable circuits. The composite ink mainly consists of soluble silver salt and adhesive rubber. Low toxic ketone was employed as the main solvent. Attributed to ultrahigh solubility of silver salt in short-chain ketone and salt-assisted dissolution of rubber, the ink can be prepared into particle-free transparent solution. As-prepared ink has a good chemical stability and can be directly filled into ballpoint pens and use to write on different substrates to form well adhesive silver salt-based composite written traces as needed. As a result of high silver salt loading, the trace can be converted into highly conductive silver nanoparticle-based composites after in situ reduction. Because of the introduction of adhesive elastomeric rubber, the as-formed conductive composite written trace can not only maintain good adhesion to various substrates but also show good conductivity under various deformations. The conductivity of written traces can be enhanced by repeated writing-reduction cycles. Different patterns can be fabricated by either direct handwriting or hand-copying. As proof-of-concept demonstrations, a typical handwriting heart-like circuit was fabricated to show its capability to work under different deformations, and a pressure-sensitive switch was also manufactured to present pressure-dependent change of resistance.

i3DP, a robust 3D printing approach enabling genetic post-printing surface modification.

Initiator integrated 3D printing, namely i3DP, was developed by incorporating a vinyl-terminated initiator into UV curable resin to make functional structural materials that enable genetic post-printing surface-initiated modification. Taking advantage of 3D printing and surface-initiated ATRP, the feasible i3DP makes 3D printed complex architectures possible for nearly any desired surface modification for various applications, for example, even pouring water into a sieve was readily achieved.

[Study on preparation of quercetin nanostructured lipid carriers and their physicochemical properties].

OBJECTIVE: To prepare quercetin nanostuctured lipid carriers (QT-NLC), and detect their physicochemical properties. METHOD: QT-NLC was prepared by emulsification ultrasonic dispersion method, and the optimum prescription was screened out by orthogonal design. Transmission electron microscope was used to observe QT-NLC morphology. Granulometer was applied to determine zeta potential, particle size and distribution. DSC was adopted for phase analysis. Centrifugal ultra-filtration method was used to determine entrapment efficiency. Dialysis method was adopted to detect drug release in vitro of preparations. RESULT: QT-NLC prepared under optimum conditions was mostly spherical grains, with the average particle size of (175 +/- 25) nm, which were distributed evenly, and zeta potential was (-23 +/- 0.3) mV. DSC results indicated that the drug was dispersed in nano-particles in a non-crystalline state, with an entrapment efficiency of (95.43 +/- 0.23)% and a drug-loading capacity of (2.38 +/- 0.24)%. The in vitro drug release was 32.2% in 2 hours, which was followed by a sustained release. CONCLUSION: Emulsification ultrasonic dispersion method is applicable for preparing QT-NLC, as nano-particles are distributed evenly, with good reliability. This processing technology is safe, reliable and highly reproducible.

Grafting of polyelectrolytes onto hydrocarbon surfaces by high-energy hydrogen induced cross-linking for making metallized polymer films.

Polyelectrolytes were grafted onto hydrocarbon surfaces by a dry-process and chemical-free approach using hydrogen projectiles with high kinetic energy but properly controlled to selectively cleave C-H bonds, on which electroless plating was carried out after loading Pd moieties by ion exchange, resulting in high quality metalized polymer films with excellent conductivity and mechanical stability.