Preparation of Superelastic, Durable, and Lightweight Composite Foams Based on Multiple Cross-Linked Network Regulated Structures

The polymer material foaming technology plays an important role in energy conservation and emission reduction. However, modulating the structure of rubber/plastic foams to achieve low weight and high resilience is still a challenge. In this paper, ethylene vinyl acetate polymer (EVA)/epoxidized natural rubber (ENR) foams are prepared by chemical foaming kettle compression molding (KCM) with multiple cross-linked network structures consisting of covalent cross-links of EVA–EVA and ENR–ENR and hydrogen-bonded cross-linked networks between hydroxyl and ester groups. As influenced by the hydrogen-bonded cross-linked networks, the cellular restructuring of EVA/ENR foams is no longer limited to changes in the rubber/plastic content. Compared to pure EVA foams, EVA/ENR foams show advantages such as a low weight (13.95 × 1010 cells/density), a higher ductility (3.42 MJ/m3), a higher resilience (50%), and superior durability (more than 200 cycles at 50% compression). Moreover, due to the binding and anchoring effect of the ENR molecular chains, the thermal stability of EVA/ENR foams is greatly enhanced, with an initial decomposition temperature of around 320 °C, compared to that of EVA foams (∼150 °C). Considering the excellent properties of the EVA/ENR foams and the low cost of the KCM, the present strategy proposes an easy-to-industrialize method of fabricating rubber/plastic composite foams with high mechanical properties

Efficient and Balanced Charge Transport Revealed in Planar Perovskite Solar Cells

Hybrid organic–inorganic perovskites have emerged as novel photovoltaic materials and hold great promise for realization of high-efficiency thin film solar modules. In this study, we unveil the ambipolar characteristics of perovskites by employing the transport measurement techniques of charge extraction by linearly increasing voltage (CELIV) and time-of-flight (TOF). These two complementary methods are combined to quantitatively determine the mobilities of hole and electron of CH₃NH₃PbI₃ perovskite while revealing the recombination process and trap states. It is revealed that efficient and balanced transport is achieved in both CH₃NH₃PbI₃ neat film and CH₃NH₃PbI₃/PC₆₁BM bilayer solar cells. Moreover, with the insertion of PC₆₁BM, both hole and electron mobilities of CH₃NH₃PbI₃ are doubled. This study offers a dynamic understanding of the operation of perovskite solar cells

Role of the MAPKs/TGF-β1/TRAF6 signaling pathway in postoperative atrial fibrillation

<div><p>Objectives</p><p>To explore the relationship between the MAPKs/TGF-β1/TRAF6 signaling pathway and atrial fibrosis in patients with rheumatic heart disease (RHD) and its role in atrial fibrillation (AF) after cardiac surgery on the basis of our previous animal study of the MAPKs/TGF-β1/TRAF6 signaling pathway in atrial fibrosis.</p><p>Methods</p><p>A total of 57 patients with RHD without a history of AF consented to left atrial biopsy. Histopathology quantified the percentage of fibrosis, and real-time PCR and western blot assessed the mRNA and protein expression of TGF-β1, TRAF6, and connective tissue growth factor (CTGF), respectively. Western blot was also used to measure the protein expression of phosphorylated MAPKs and TGF-β-activated kinase 1 (TAK1). Serum angiotensin II (Ang II) levels were assayed using enzyme-linked immunosorbent assay (ELISA).</p><p>Results</p><p>Eighteen patients developed AF, whereas 39 remained in sinus rhythm (SR). The severity of atrial fibrosis was significantly higher in patients who developed AF versus those who remained in SR; the mRNA and protein expression of TGF-β1, TRAF6 and CTGF were significantly higher in patients with AF. The protein expression of phosphorylated MAPKs and TAK1 was significantly increased in patients who developed AF compared with the patients who remained in SR. Serum Ang II levels were significantly higher in patients who developed AF versus those who remained in SR.</p><p>Conclusion</p><p>The MAPKs/TGF-β1/TRAF6 signaling pathway is involved in atrial fibrosis in patients with RHD, which results in the occurrence of AF after cardiac surgery.</p></div

Synthesis of Multi-Au-Nanoparticle-Embedded Mesoporous Silica Microspheres as Self-Filtering and Reusable Substrates for SERS Detection

Surface-enhanced Raman-scattering-based (SERS-based) biosensing in biological fluids is constrained by nonspecific macromolecule adsorptions and disposable property of the SERS substrate. Here, novel multi-Au-nanoparticle-embedded mesoporous silica microspheres (AuNPs/mSiO₂) were prepared using a one-pot method, which served as reliable substrates for SERS enhancement associated with salient features of self-filtering ability and reusability. The fabrication and physical characterization of AuNPs/mSiO₂ microspheres were discussed, and SERS activity of this novel substrate was investigated by using 4-mercaptobenzoic acid (4-MBA) as Raman probe. The responses of our substrates to Raman intensities exhibited a SERS enhancement factor of 2.01 × 10⁷ and high reproducibility (relative standard deviation of 6.13%). Proof-of-concept experiments were designed to evaluate the self-filtering ability of the substrates in bovine serum albumin (BSA) and human serum solution, separately. The results clearly demonstrate that mesoporous SiO₂ can serve as a molecular sieve via size exclusion and avoid Raman signal interference of biomacromolecules in biological fluids. Subsequently, feasibility of practical application of AuNPs/mSiO₂ microspheres was assessed by quantitative detection of methotrexate (MTA) in serum. The method exhibited good linearity between 1 and 110 nM with the correlation coefficients of 0.996, which proved that the obtained AuNPs/mSiO₂ microspheres were good SERS substrates for determination of small biomolecules directly in biological fluids without need of manipulating samples. In addition, the substrate maintained its SERS response during multiple cycles, which was evaluated by recording Raman signals for 4-MBA before and after thermal annealing, thereby demonstrating the high thermostability and satisfactory reusability. These results offered the AuNPs/mSiO₂ microspheres attractive advantages in their SERS biosensing

Tunable Exciton Dissociation at the Organic/Metal Electrode Interface

Understanding of the dynamic optoelectronic processes at the organic/metal electrode interface is crucial to the interface engineering of organic electronics. Here we present the systematic studies of exciton dissociation of p-type organic semiconductor at the organic/Ag interface. The interfacial dissociation of photogenerated excitons at the <i>N</i>,<i>N</i>′-di­(1-naphthyl)-<i>N</i>,<i>N</i>′-diphenyl-(1,1′-biphenyl)-4,4′-diamine (NPB)/Ag interface was systematically investigated using the transient photovoltage technique as a proof-of-concept. The results indicate that two types of exciton dissociationtransfer of either electrons or holes to the metal electrodecoexist at the organic/metal electrode interface. This conclusion is further confirmed by two additional experimentsthe current response of the NPB/Ag interface to light illumination under constant biases and the successive light current–voltage measurements under constant illumination. Moreover, the proportion of two types of dissociations was found to be tunable upon the oxidation of the silver electrode or the insertion of a lithium fluoride interlayer to the NPB/Ag interface. These results may be useful for interface engineering of organic photovoltaic cells