Polyphenol-Based Bicontinuous Porous Spheres Via Amine-Mediated Polymerization-Induced Fusion Assembly.

Bicontinuous porous materials, which possess 3D interconnected network and pore channels facilitating the mass diffusion to the interior of materials, have demonstrated their promising potentials in a large variety of research fields. However, facile construction of such complex and delicate structures is still challenging. Here, an amine-mediated polymerization-induced fusion assembly strategy is reported for synthesizing polyphenol-based bicontinuous porous spheres with various pore structures. Specifically, the fusion of pore-generating template observed by TEM promotes the development of bicontinuous porous networks that are confirmed by 3D reconstruction. Furthermore, the resultant bicontinuous porous carbon particles after pyrolysis, with a diameter of ≈600 nm, a high accessible surface area of 359 m2 g-1, and a large pore size of 40-150 nm manifest enhanced performance toward the catalytic degradation of sulfamethazine in water decontamination. The present study expands the toolbox of interfacial tension-solvent-dependent porous spheres while providing new insight into their structure-property relationships.

Surface Functionalization with Polymer Brushes via Surface-Initiated Atom Transfer Radical Polymerization: Synthesis, Applications, and Current Challenges.

Polymer brushes have received great attention in recent years due to their distinctive properties and wide range of applications. The synthesis of polymer brushes typically employs surface-initiated atom transfer radical polymerization (SI-ATRP) techniques. To realize the control of the polymerization process in different environments, various SI-ATRP techniques triggered by different stimuli have been developed. This review focuses on the latest developments in different stimuli-triggered SI-ATRP methods, such as electrochemically mediated, photoinduced, enzyme-assisted, mechanically controlled, and organocatalyzed ATRP. Additionally, SI-ATRP technology triggered by a combination of multiple stimuli sources is also discussed. Furthermore, the applications of polymer brushes in lubrication, biological applications, antifouling, and catalysis are also systematically summarized and discussed. Despite the advancements in the synthesis of various types of 1D, 2D, and 3D polymer brushes via controlled radical polymerization, contemporary challenges remain in the quest for more efficient and straightforward synthetic protocols that allow for precise control over the composition, structure, and functionality of polymer brushes. We anticipate the readers could promote the understanding of surface functionalization based on ATRP-mediated polymer brushes and envision future directions for their application in surface coating technologies.

Electrochemically Mediated Surface-Initiated Atom Transfer Radical Polymerization by ppm of CuII/Tris(2-pyridylmethyl)amine.

Atom transfer radical polymerization (ATRP) is one of the most widely used methods for modifying surfaces with functional polymer films and has received considerable attention in recent years. Here, we report an electrochemically mediated surface-initiated ATRP to graft polymer brushes onto solid substrates catalyzed by ppm amounts of CuII/TPMA in water/MeOH solution. We systematically investigated the type and concentrations of copper/ligand and applied potentials correlated to the polymerization kinetics and polymer brush thickness. Gradient polymer brushes and various types of polymer brushes are prepared. Block copolymerization of 2-hydroxyethyl methacrylate (HEMA) and 3-sulfopropyl methacrylate potassium salt (PSPMA) (poly(HEMA-b-SPMA)) with ultralow ppm eATRP indicates the remarkable preservation of chain end functionality and a pronounced "living" characteristic feature of ppm-level eATRP in aqueous solution for surface polymerization.

Tunable Hierarchically Structured Meso-Macroporous Carbon Spheres from a Solvent-Mediated Polymerization-Induced Self-Assembly.

Herein, we report a versatile solvent-mediated polymerization-induced self-assembly (PISA) strategy to directly synthesize highly N-doped hierarchically porous structured carbon spheres with a tunable meso-macroporous configuration. The introduction of intermolecular hydrogen bonds is verified to enhance the interfacial interactions between block copolymers, oil droplets, and polyphenols. Moreover, the dominant hydrogen-bond-driven interactions can be systematically manipulated by selecting different cosolvent systems to generate diverse porous structures from the transformation of micellar and precursor co-assembly. Impressively, hierarchically structured meso-macroporous N-doped carbon spheres present simultaneously tunable sphere sizes and mesopores and macropores, ranging from 1.2 µm, 9/50 and 227 nm to 1.0 µm, 40, and 183 nm and 480, 24, and 95 nm. As a demonstration, dendritic-like N-doped hierarchically meso-macroporous carbon spheres manifest excellent enzyme-like activity, which is attributed to the continuous mass transport from the multiordered porosity. The current study provides a new platform for the synthesis of novel well-defined porous materials.

A Strong and Double-sided Self-Adhesive Hydrogel Sensor.

Flexible self-adhesive hydrogel sensors are attracting considerable concerns in recent years. However, creating a self-adhesive hydrogel sensor with excellent mechanical properties remains to be challenging. Herein, a double-sided self-adhesive hydrogel capable of strain sensor with high strength is demonstrated by penetration strategy. The middle poly(acrylic acid)-polyacrylamide/Fe3+ (PAA-PAM/Fe3+ ) tough layer endows the double-sided self-adhesive hydrogel with high mechanical properties, while the bilateral poly[2-(methacryloyloxy) ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide-polyacrylamide (PSBMA-PAM) adhesive layers are used to ensure excellent adhesiveness on diverse substrates. The tough layer of the double-sided self-adhesive hydrogel sensor shows a strong interface bonding force against the adhesive layer. The double-sided self-adhesive hydrogel sensor enables excellent adhesiveness on diverse substrates. More importantly, it can accurately detect different strains and human motions as a self-adhesive hydrogel strain sensor. This work manifests a new route of structural design to develop a self-adhesive hydrogel sensor with excellent mechanical properties that is suitable for a wide range of applications.

In Situ Surface-Initiated ATRP Mediated by Gallium-Based Liquid Metal Nanodroplets.

Surface-initiated atom transfer radical polymerization (SI-ATRP) is one of the most popular methods for surface modifications with functional polymer films, which has attracted significant attention in recent years. Herein, a facile method of gallium-based liquid metal (GLM) nanodroplets mediated SI-ATRP to prepare polymer brushes on GLM surfaces is reported. The ATRP initiator modified GLM (GLM-Br) nanodroplets act as a substrate for the in situ SI-ATRP and participate as a reducing agent to reduce Cu(II) deactivators to Cu(I) activators. UV-vis spectra confirm the feasibility of the in situ SI-ATRP and indicate that the thickness and density of polymer brushes play an important role in performing a successful ATRP on GLM nanodroplets surfaces. Homo- and block copolymers, poly(3-sulfopropyl methacrylate potassium salt) (PSPMA) and poly((2-dimethylamino)ethyl methacrylate-b-(3-sulfopropyl methacrylate potassium salt)) P(DMAEMA-b-SPMA) are successfully grafted to the GLM nanodroplets. Polymer brushes modified GLM nanodroplets show potential applications such as friction reduction and oil-water emulsion separation. GLM nanodroplets mediated SI-ATRP provides a novel and robust approach to preparing multifunctional GLM nanodroplets for different applications.

Driving Polymer Brushes from Synthesis to Functioning.

The great success of controlled radical polymerizations has encouraged researchers to develop more facile and robust approaches for surface-initiated polymerizations (SIPs) to fabricate polymer brushes, even for non-experts. In recent years, external-stimuli-mediated radical polymerization methods have come to the fore as SIPs because of their less rigorous synthetic procedures and high controllability, which expand the opportunities for synthesizing macromolecules with desired chemical compositions and structures, as well as tailor-made polymers and bioconjugates that show broad applicability and physiological compatibility. This review discusses the latest developments in surface-initiated polymerization methods, in particular, external-stimuli mediated atom transfer radical polymerization (ATRP), photo-induced polymerizations, and reversible addition-fragmentation chain transfer (RAFT) polymerization, as well as other methods and their combination for the application in surface grafting. The implementation of these methods is of great interest due to their unique possibilities to temporally control a polymerization process, fast and straightforward polymerization, and environmentally benign features, which lead to established and emerging applications in biolubrication, antifouling, and biosensing.

Controllable Synthesis of Polyphenol Spheres via Amine-Catalyzed Polymerization-Induced Self-Assembly.

A facile and general strategy for preparing uniform and multifunctional polyphenol-based colloidal particles through amine-catalyzed polymerization-induced self-assembly is described. The size and interfacial adhesion of polyphenol spheres can be easily controlled over a wide range via adjusting the concentration of the cosolvent and monomer. Moreover, the polyphenol spheres showed excellent thermal and chemical stability and highly active properties and could efficiently deplete the reactive oxygen species (ROS), which are helpful for in vivo ROS regulation for inflammatory therapeutic. The accessible and versatile method provides a feasible way for the rational engineering of multifunctional polyphenol spheres, which have great potential in many fields.

A gradient boosting tree model for multi-department venous thromboembolism risk assessment with imbalanced data.

Venous thromboembolism (VTE) is the world's third most common cause of vascular mortality and a serious complication from multiple departments. Risk assessment of VTE guides clinical intervention in time and is of great importance to in-hospital patients. Traditional VTE risk assessment methods based on scaling tools, which always require rules carefully designed by human experts, are difficult to apply to large-population scenarios since the manually designed rules are not guaranteed to be accurate to all populations. In contrast, with the development of the electronic health record (EHR) datasets, data-driven machine-learning-based risk assessment methods have proven superior predictability in many studies in recent years. This paper uses the gradient boosting tree model to study the VTE risk assessment problem with multi-department data. There exist two distinct characteristics of VTE data collected at the level of the entire hospital: its wide distribution and heterogeneity across multiple departments. To this end, we consider the prediction task over multiple departments as a multi-task learning process, and introduce the algorithm of a task-aware tree-based method TSGB to tackle the multi-task prediction problem. Although the introduction of multi-task learning improves overall across-department performance, we reveal the problem of task-wise performance decline while dealing with imbalanced VTE data volume. According to the analysis, we finally propose two variants of TSGB to alleviate the problems and further boost the prediction performance. Compared with state-of-the-art rule-based and multi-task tree-based methods, the experimental results show the proposed methods not only improve the overall across-department AUC performance effectively, but also ensure the improvement of performance over every single department prediction.

Comparison of outcome between percutaneous pedicle screw fixation and the Mini-Open Wiltse Approach with pedicle screw fixation for neurologically intact thoracolumbar fractures: A retrospective study.

BACKGROUND: The purpose of this study was to compare the outcome between percutaneous pedicle screw fixation (PPSF) and the mini-open Wiltse approach with pedicle screw fixation (MWPSF) for neurologically intact thoracolumbar fractures. METHODS: From January 2017 to January 2019, ninety-four patients with neurologically intact thoracolumbar fractures were included in this study. In this retrospective study, forty-nine patients were operated with the PPSF and forty-five patients received MWPSF. The clinical information, surgery-related results and radiographic outcome were collected and compared between the two groups. RESULTS: There was no significant difference between the two groups in total length of incisions, blood loss, post-operative hospitalization time, visual analog scale (VAS) score and Oswestry disability index (ODI) score. There was also no significant difference in the accuracy rate of pedicle screw placement between two groups; however, the facet joint violation (FJV) was significantly higher in the PPSF group. The atrophic area of multifidus muscle in the PPSF group is significantly larger than that in the MWPSF group and the operative time of MWPSF group was shorter than that in the PPSF group. Meanwhile, the PPSF group obtaining significantly more cumulative exposure to radiation (p < 0.001). The result of vertebral body angle (VBA), Cobb's angle and AVH rate in the MWPSF group were significantly better than those in the PPSF group at the last post-operative follow-up. CONCLUSIONS: Both minimally invasive treatment techniques (PPSF and MWPSF) are safe and effective in treatment of neurologically intact thoracolumbar fractures. Nevertheless, our results indicate that MWPSF may be a better choice for neurologically intact thoracolumbar fractures, since it protects multifidus muscle, and decreases facet joint violation, operation time, as well as radiation exposure. In addition, MWPSF was associated with better reduction of kyphosis.

Successive Redox-Reaction-Triggered Interface Radical Polymerization for Growing Hydrogel Coatings on Diverse Substrates.

Growing lubricating hydrogel coatings in controllable manners on diverse material surfaces demonstrates promising applications. Here, a surface modification method is reported for in situ growing hydrogel coatings onto surfaces of diverse substrates in the absence of UV assistance. It is performed by decorating substrates with a universal mussel-inspired synthetic adhesive with catechol groups. Upon being immersed in reaction solution, these groups can assist substrate bonding and in situ capture and reduce Fe3+ into Fe2+ for decomposing S2 O8 2- into SO4 - ⋅ catalytically at the interface to initiate interface polymerization of monomers. As a result, hydrogel coatings with controllable thickness could be grown on surfaces of arbitrary substrates to change their surface characteristics regardless of materials size, category, geometry and transparency, implying considerable potential in surface engineering.

A novel hierarchical machine learning model for hospital-acquired venous thromboembolism risk assessment among multiple-departments.

Venous thromboembolism (VTE) is a common vascular disease and potentially fatal complication during hospitalization, and so the early identification of VTE risk is of significant importance. Compared with traditional scale assessments, machine learning methods provide new opportunities for precise early warning of VTE from clinical medical records. This research aimed to propose a two-stage hierarchical machine learning model for VTE risk prediction in patients from multiple departments. First, we built a machine learning prediction model that covered the entire hospital, based on all cohorts and common risk factors. Then, we took the prediction output of the first stage as an initial assessment score and then built specific models for each department. Over the duration of the study, a total of 9213 inpatients, including 1165 VTE-positive samples, were collected from four departments, which were split into developing and test datasets. The proposed model achieved an AUC of 0.879 in the department of oncology, which outperformed the first-stage model (0.730) and the department model (0.787). This was attributed to the fully usage of both the large sample size at the hospital level and variable abundance at the department level. Experimental results show that our model could effectively improve the prediction of hospital-acquired VTE risk before image diagnosis and provide decision support for further nursing and medical intervention.

Surface Grafting "Band-Aid" for "Everyone": Filter Paper-Assisted Surface-Initiated Polymerization in the Presence of Air.

We report herein a facile and generalized approach to the modification of solid surfaces with polymer brushes under ambient conditions: filter paper-assisted surface-initiated Cu0 -mediated controlled radical polymerization (PSI-CuCRP). The polymerization solution wetted filter paper is sandwiched between a copper plate and an initiator-modified substrate, which allows the creation of a surface-initiated polymerization (SIP) "band-aid" so that everyone can perform the surface grafting selectively with good control over the quality of the polymer brushes employing low concentration and microliter amounts of the monomer solution. The versatility of this method is demonstrated by grafting different homo-, block-, and multicomponent polymer brushes by using the same activation system and reaction conditions, the polymerization process can be precisely controlled to yield uniform polymers and show high chain-end functionality which is exemplified by in situ tetra-copolymerization. The combination of photolithography and paper cutting enables to prepare arbitrary three-dimensional patterned polymer brushes on the surface.

Facile Fabrication of Bio- and Dual-Functional Poly(2-oxazoline) Bottle-Brush Brush Surfaces.

Poly(2-oxazoline)s (POx) bottle-brush brushes have excellent biocompatible and lubricious properties, which are promising for the functionalization of surfaces for biomedical devices. Herein, a facile synthesis of POx is reported which is based bottle-brush brushes (BBBs) on solid substrates. Initially, backbone brushes of poly(2-isopropenyl-2-oxazoline) (PIPOx) were fabricated via surface initiated Cu0 plate-mediated controlled radical polymerization (SI-Cu0 CRP). Poly(2-methyl-2-oxazoline) (PMeOx) side chains were subsequently grafted from the PIPOx backbone via living cationic ring opening polymerization (LCROP), which result in ≈100 % increase in brush thickness (from 58 to 110 nm). The resultant BBBs shows tunable thickness up to 300 nm and high grafting density (σ) with 0.42 chains nm-2 . The synthetic procedure of POx BBBs can be further simplified by using SI-Cu0 CRP with POx molecular brush as macromonomer (Mn =536 g mol-1 , PDI=1.10), which results in BBBs surface up to 60 nm with well-defined molecular structure. Both procedures are significantly superior to the state-of-art approaches for the synthesis of POx BBBs, which are promising to design bio-functional surfaces.

Polymer Brushes on Hexagonal Boron Nitride.

Direct covalent functionalization of large-area single-layer hexagonal boron nitride (hBN) with various polymer brushes under mild conditions is presented. The photopolymerization of vinyl monomers results in the formation of thick and homogeneous (micropatterned, gradient) polymer brushes covalently bound to hBN. The brush layer mechanically and chemically stabilizes the material and allows facile handling as well as long-term use in water splitting hydrogen evolution reactions.

Mussel-Inspired Two-Dimensional Freestanding Alkyl-Polydopamine Janus Nanosheets.

Mussel-inspired two-dimensional freestanding, alkyl-polydopamine (alkyl-PDA) Janus nanosheets, with a well-controlled nanometer thickness and a lateral size of up to micrometers, have been developed. A self-assembled octadecylamine (ODA) bilayer is used as the reactive template for the dopamine polymerization, resulting in the formation of well-defined nanosheets. The alkyl-PDA nanosheets show an amphiphilic nature with hydrophilic PDA and hydrophobic alkyl chains on opposing sides. The nanosheets can be used to functionalize many substrates and is dependent on the configuration of surface of the nanosheets. The nanosheets are quite stable, as the morphology is preserved after carbonization at 900 °C. Post-modification of the nanosheets can be easily achieved because of the reactive nature of PDA. This work will provide a new strategic approach for fabricating polymeric Janus nanosheets, which can find applications for surface modifications, catalyst supports, and guided self-assembly.

A Nitrogen-Rich 2D sp2 -Carbon-Linked Conjugated Polymer Framework as a High-Performance Cathode for Lithium-Ion Batteries.

A two-dimensional (2D) sp2 -carbon-linked conjugated polymer framework (2D CCP-HATN) has a nitrogen-doped skeleton, a periodical dual-pore structure and high chemical stability. The polymer backbone consists of hexaazatrinaphthalene (HATN) and cyanovinylene units linked entirely by carbon-carbon double bonds. Profiting from the shape-persistent framework of 2D CCP-HATN integrated with the electrochemical redox-active HATN and the robust sp2 carbon-carbon linkage, 2D CCP-HATN hybridized with carbon nanotubes shows a high capacity of 116 mA h g-1 , with high utilization of its redox-active sites and superb cycling stability (91 % after 1000 cycles) and rate capability (82 %, 1.0 A g-1 vs. 0.1 A g-1 ) as an organic cathode material for lithium-ion batteries.

Functional connectivity decreases in autism in emotion, self, and face circuits identified by Knowledge-based Enrichment Analysis.

A powerful new method is described called Knowledge based functional connectivity Enrichment Analysis (KEA) for interpreting resting state functional connectivity, using circuits that are functionally identified using search terms with the Neurosynth database. The method derives its power by focusing on neural circuits, sets of brain regions that share a common biological function, instead of trying to interpret single functional connectivity links. This provides a novel way of investigating how task- or function-related networks have resting state functional connectivity differences in different psychiatric states, provides a new way to bridge the gap between task and resting-state functional networks, and potentially helps to identify brain networks that might be treated. The method was applied to interpreting functional connectivity differences in autism. Functional connectivity decreases at the network circuit level in 394 patients with autism compared with 473 controls were found in networks involving the orbitofrontal cortex, anterior cingulate cortex, middle temporal gyrus cortex, and the precuneus, in networks that are implicated in the sense of self, face processing, and theory of mind. The decreases were correlated with symptom severity.

Dual-Graphene Rechargeable Sodium Battery.

Sodium (Na) ion batteries are attracting increasing attention for use in various electrical applications. However, the electrochemical behaviors, particularly the working voltages, of Na ion batteries are substantially lower than those of lithium (Li) ion batteries. Worse, the state-of-the-art Na ion battery cannot meet the demand of miniaturized in modern electronics. Here, we demonstrate that electrochemically exfoliated graphene (EG) nanosheets can reversibly store (PF6- ) anions, yielding high charging and discharging voltages of 4.7 and 4.3 V vs. Na+ /Na, respectively. The dual-graphene rechargeable Na battery fabricated using EG as both the positive and negative electrodes provided the highest operating voltage among all Na ion full cells reported to date, together with a maximum energy density of 250 Wh kg-1 . Notably, the dual-graphene rechargeable Na microbattery exhibited an areal capacity of 35 µAh cm-2 with stable cycling behavior. This study offers an efficient option for the development of novel rechargeable microbatteries with ultra-high operating voltage and high energy density.

Grafting Poly(ethylene glycol) Onto Single-Walled Carbon Nanotubes by Living Anionic Ring-Opening Polymerization.

Recent years, many methods have been developed to widen the practical application of single-walled carbon nanotubes (SWCNTs). Among them, PEGylation is a general strategy to endow functionality, biocompatibility as well as its good solubility. In this paper, poly(ethylene glycol) (PEG) is successfully grafted onto SWCNTs through living anionic ring-opening polymerization of ethylene oxide (EO). By controlling the amount of monomer and initiator, a series of PEGylated SWCNTs with different PEG molecular weight and density are prepared. Then, the as-prepared SWCNTs have been verified by thermogravimetric analyses (TGA), Raman spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS). Finally, the protein resistance property of the PEGylated SWCNTs is investigated. It is found that these PEGylated SWCNTs have a good protein resistance property and the higher the content of PEG grafted on the SWCNTs, the less adsorption amount of BSA and the larger capacity to resist protein absorption. This work provides a novel method to prepare PEGylated SWCNTs.