Dendrimer-assisted defect and morphology regulation for improving optical, hyperthermia, and microwave-absorbing features.

Electromagnetic pollution and cancer are phenomena that essentially endanger the future of humanity. Herein, multiple approaches are being proposed to solve the aforementioned issues. Recent studies have demonstrated that by regulating the morphology, defect, and phase of materials, their microwave absorbing, optical, and hyperthermia properties are tunable. Calcium ferrite with proper dielectric, magnetic, and biocompatible characteristics was chosen as a substantial candidate to promote its microwave-absorbing properties by regulating its structure. Spinel CaFe2O4 was synthesized through sol-gel and solvothermal routes and its phase, defect, and morphology were manipulated using innovative procedures. Glucose was applied as conventional defecting and templating agent; interestingly, a dendrimer was designed to bear and form nanoparticles. More importantly, a novel reductive process was designed to fabricate one-put Ca/Fe3O4 using a solvothermal method. Particularly, polypropylene (PP) was employed as a practical polymeric matrix to fabricate the eventual product. Structures were molded at a low filling ratio to evaluate their optical and microwave-absorbing performance. As expected, defects, morphology, and phase play a pivotal role in tuning the optical and microwave-absorbing properties of calcium ferrite derivates. Interestingly, the dendrimer-assisted (D-A) formation of CaFe2O4 demonstrated a fascinating reflection loss (RL) of 70.11 dB and an efficient bandwidth (RL ≤ -20 dB) of 7.03 GHz with ultralow thickness (0.65 mm) and filling ratio (10 wt%), attaining proper shielding efficiency (SE) and hyperthermia desirable for its practical application as a material for shielding buildings and cancer therapy. The presented perspective develops new inspirations for architecting microwave absorbing/shielding materials with advanced applications in therapeutic issues.

Electronic Modulation Strategy for Mass-Producible Ultrastrong Multifunctional Biomass-Based Fiber Aerogel Devices: Interfacial Bridging.

The emergence of green flexible aerogel electronics based on natural materials is expected to solve part of the global environmental and energy crisis. However, it is still challenging to achieve large-scale production and multifunctional stable applications of natural biomass fiber aerogel (BFA) materials. Herein, we exploit the interfacial bridging between the flower-type titanium dioxide nanoarray (FTNA) and natural fiber substrates to modulate the electronic structure and loss mechanism to achieve multifunctional properties. Specifically, the fibrous substrate with wrinkled features induces lattice strain in titania through precise interfacial bridging, effectively improving the intrinsic properties of the BFA materials. This interfacial bridging regulation strategy is also confirmed by X-ray absorption fine structure spectroscopy (XAS). More importantly, the construction of BFA products for different macroscopic and multifunctional applications through simple processing methods will facilitate the transition from natural materials to multifunctional flexible electronics. Therefore, the as-prepared blanket-type BFA (TCBFA) has good mechanical properties, electromagnetic protection properties, thermal stealth properties, high-temperature flame retardancy, and UV resistance. Meanwhile, the membrane-type (TCBFAM) multifunctional wearable fiber aerogel device exhibits superior flexibility, efficient Joule heating performance, and a smart response. This regulation strategy provides another concept for the design and innovation of green multifunctional fiber-integrated aerogels.

"Three-in-One" Multi-Scale Structural Design of Carbon Fiber-Based Composites for Personal Electromagnetic Protection and Thermal Management.

Wearable devices with efficient thermal management and electromagnetic interference (EMI) shielding are highly desirable for improving human comfort and safety. Herein, a multifunctional wearable carbon fibers (CF) @ polyaniline (PANI) / silver nanowires (Ag NWs) composites with a "branch-trunk" interlocked micro/nanostructure were achieved through "three-in-one" multi-scale design. The reasonable assembly of the three kinds of one-dimensional (1D) materials can fully exert their excellent properties i.e., the superior flexibility of CF, the robustness of PANI, and the splendid conductivity of AgNWs. Consequently, the constructed flexible composite demonstrates enhanced mechanical properties with a tensile stress of 1.2 MPa, which was almost 6 times that of the original material. This is mainly attributed to the fact that the PNAI (branch) was firmly attached to the CF (trunk) through polydopamine (PDA), forming a robust interlocked structure. Meanwhile, the composite possesses excellent thermal insulation and heat preservation capacity owing to the synergistically low thermal conductivity and emissivity. More importantly, the conductive path of the composite established by the three 1D materials greatly improved its EMI shielding property and Joule heating performance at low applied voltage. This work paves the way for rational utilization of the intrinsic properties of 1D materials, as well as provides a promising strategy for designing wearable electromagnetic protection and thermal energy management devices.

Multi-interfacial engineering in the hierarchical self-assembled micro-nano dielectric aerogel for wide-band absorption and low infrared emissivity.

Radar-infrared (IR) compatible stealth can satisfy the characteristics of excellent electromagnetic wave attenuation property and low infrared emissivity. However, concurrently satisfying these demands is still a great challenge at present. Herein, multi-interfacial engineering strategy was proposed for the preparation of radar-IR compatible stealth materials. ZnO has a high electron binding energy and a large band gap at room temperature, and doping with sulphide can increase the concentration of unconstrained carriers. Therefore, bimetallic sulphide aerogels loaded with ZnO were prepared by means of carbonization and vulcanization, combined with freeze-drying method. When the filling ratio is 20 %, an absorption bandwidth (fe) of 6.62 GHz at a matching thickness of 2.0 mm and a reduction in IR emissivity from 0.920 to 0.539 in the 8-14 µm band are achieved. This work provides a guidance to design and synthesize high-performance absorbers by multi-interfacial engineering for IR-radar compatible stealth application.

Ultrabroad Microwave Absorption Ability and Infrared Stealth Property of Nano-Micro CuS@rGO Lightweight Aerogels.

Developing ultrabroad radar-infrared compatible stealth materials has turned into a research hotspot, which is still a problem to be solved. Herein, the copper sulfide wrapped by reduced graphene oxide to obtain three-dimensional (3D) porous network composite aerogels (CuS@rGO) were synthesized via thermal reduction ways (hydrothermal, ascorbic acid reduction) and freeze-drying strategy. It was discovered that the phase components (rGO and CuS phases) and micro/nano structure (microporous and nanosheet) were well-modified by modulating the additive amounts of CuS and changing the reduction ways, which resulted in the variation of the pore structure, defects, complex permittivity, microwave absorption, radar cross section (RCS) reduction value and infrared (IR) emissivity. Notably, the obtained CuS@rGO aerogels with a single dielectric loss type can achieve an ultrabroad bandwidth of 8.44 GHz at 2.8 mm with the low filler content of 6 wt% by a hydrothermal method. Besides, the composite aerogel via the ascorbic acid reduction realizes the minimum reflection loss (RLmin) of - 60.3 dB with the lower filler content of 2 wt%. The RCS reduction value can reach 53.3 dB m2, which effectively reduces the probability of the target being detected by the radar detector. Furthermore, the laminated porous architecture and multicomponent endowed composite aerogels with thermal insulation and IR stealth versatility. Thus, this work offers a facile method to design and develop porous rGO-based composite aerogel absorbers with radar-IR compatible stealth.

Flexible and transparent silver nanowires/biopolymer film for high-efficient electromagnetic interference shielding.

Flexible and transparent conductive films are highly desirable in some optoelectronic devices, such as smart windows, touch panels, as well as displays and electromagnetic protection field. Silver nanowire (Ag NW) has been considered as the best material to replace indium tin oxide (ITO) to fabricate flexible transparent electromagnetic interference (EMI) shielding films due to its superior comprehensive performance. However, the common substrates supporting Ag NWs require surface modification to enhance the adhesion with Ag NWs. In this work, a flexible and transparent Ag NWs EMI shielding film with sandwich structure through a facile rod-coating method, wherein Ag NWs network were embedded between biodegradable gelatin-based substrate and cover layer. The interfacial adhesion between Ag NWs and gelatin-based layers was enhanced by hydrogen-bonding interaction and swelling effect without any pretreatment. The shielding effectiveness (SE) of the G/Ag NW/G (G represents gelatin-based layer) film reaches 37.74 dB at X band with an optical transmittance of 72.0 %. What's more, the flexible gelatin-based layer and encapsulated structure endow the resultant G/Ag NW/G film integrating excellent mechanical properties, reliable durability, antioxidation, as well as anti-freezing performance. This work paves a new way for fabricating flexible transparent EMI shielding films.

Interleukin-33 Promotes Th2/Th17 Response in Eosinophilic and Non-Eosinophilic Nasal Polyps.

BACKGROUND: Interleukin-33 (IL-33) is reported to be involved in Th2-skewed eosinophilic inflammation. A recent study also found that IL-33 exerted opposite effects on Th17 response in different diseases. However, the role of IL-33 in chronic rhinosinusitis with nasal polyps (NPs) was not explored. OBJECTIVES: The purpose of this study was to investigate the expression and function of IL-33 in chronic rhinosinusitis with NPs. MATERIALS AND METHODS: NP tissues from 60 NP patients and normal tissues of the inferior turbinate from 20 controls were sampled in operation. Immunochemistry was performed to identify eosinophilic or non-eosinophilic NPs. The expressions of IL-33 and Th1/2/17 cytokines were compared between different subtypes of NPs. The effect of IL-33 on Th response was detected in dispersed nasal polyp cells (DNPCs), and the signaling pathways involved in the process were detected using Western blot. RESULTS: The concentration of IL-33 was significantly elevated in both eosinophilic and non-eosinophilic NPs compared with controls. By in vitro study, we found that IL-33 can induce IL-4 and IL-5 production from eosinophilic DNPCs through the PI3K/AKT pathway, whereas IL-33 can induce IL-17 production from non-eosinophilic DNPCs through the ERK1/2 pathway. CONCLUSION: IL-33 is involved in Th2/Th17 response in NPs. Our study suggests that different types of NPs need a different treatment target.

Genetic screening involving 101 hot spots for neonates not passing newborn hearing screening and those random recruited in Dongguan.

In order to investigate essential molecular causes for hearing loss and mutation frequency of deafness-related genes, 1315 newborns who did not pass the Newborn Hearing Screening (NHS) (audio-no-pass) and 1000 random-selected infants were subjected to detection for 101 hotspot mutations in 18 common deafness-related genes. Totally, 23 alleles of 7 deafness genes were detected out. Significant difference (χ2 = 25.320, p = 0.000) existed in causative mutation frequency between audio-no-pass group (81/1315, 6.160%) and random-selected cohort (18/1000, 1.80%). Of the genes detected out, GJB2 gene mutation was with significant difference (χ2 = 75.132, p = 0.000) between audio-no-pass group (417/1315, 31.711%) and random-selected cohort (159/1000, 15.900%); c.109G > A was the most common allele, as well as the only one with significantly different allele frequency (χ2 = 79.327, p = 0.000) between audio-no-pass group (392/1315, 16.84%) and random-selected cohort (140/1000, 7.55%), which suggested c.109G > A mutation was critical for newborns' hearing loss. This study performed detection for such a large scale of deafness-associated genes and for the first time compared mutations between audio-no-pass and random-recruited neonates, which not only provided more reliable DNA diagnosis result for medical practioners and enhanced clinical care for the newborns, but gave more accurate estimation for mutation frequency.

Enhanced Low-Frequency Electromagnetic Properties of MOF-Derived Cobalt through Interface Design.

It is still a formidable challenge to ameliorate the low-frequency electromagnetic property of conventional microwave-absorbing materials, which may be conquered by the coexistence of both strong dielectric and magnetic loss ability in low-frequency range and the perfect balance between complex permittivity and permeability with the help of structural design. Herein, by virtue of appropriate composition and structure of Co3[HCOO]6·dimethylformamide parallelepipeds, one-dimensional spongelike metallic Co can be directly synthesized for the first time with strong magnetic loss in the low-frequency range. Furthermore, attenuation ability and impedance matching condition have been improved through the construction of interfacial structures between inner cobalt and surface carbon. With the structure of carbon changed from fragments to vertically aligned nanoflakes and eventually to a thick layer with extra fragments, the dielectric loss would be continuously strengthened, while the magnetic loss maintains well, followed by a remarkable decline. A perfect balance between dielectric and magnetic loss has been achieved by sample S-Co/C-0.3 with minimum reflection loss value around -20 dB and effective absorption frequency range about 3.84 GHz in the C band. Excellent microwave absorption performance can also be realized in X and Ku bands. In addition, as-prepared Co and Co/C composites can also be potentially applied in electromagnetic shielding. The findings may pave the way for the manufacture of metal-based metal-organic framework derivatives and the design of lightweight low-frequency electromagnetic materials.

[Mechanism of pigment content on infrared emissivity of composite coatings].

Polyurethane (PU)/flaky metal composite coatings were prepared by using PU and flaky metal powders as adhesives and pigments, respectively. The infrared emissivity of coatings with different metal content was measured by infrared emissometer, and the microstructure of PU/flaky metal composite coatings was observed by scanning electron microscopy. The results of infrared emissivity measurement indicate that the emissivity changes significantly with increasing metal content and presents a "U" type. The results of microstructure observation indicate that PU/flaky metal composite coatings have one-dimensional photonic structural characteristics. According to the microstructure characteristics, the optical reflection spectra of one-dimensional photonic structure in PU/flaky metal composite coatings with different metal content were simulated, and the results show that "U" type variation of emissivity with increasing metal content is derived from the blueshift of reflection peak wavelength with increasing metal content of one-dimensional photonic structure in coatings.