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BACKGROUND: Migraine is the most common primary headache among children and adolescents. The aim of this meta-analysis was to evaluate the efficacy and safety of antiepileptic drugs in the prevention of pediatric migraine. METHODS: PubMed, Cochrane Library, EMBASE and Chinese National Knowledge Infrastructure (CNKI) databases were searched for eligible published RCTs from January 1970 to June 2020. Migraine frequency and ≥50% response rate were measured as the efficacy outcomes. We used “Risk of Bias” tool for quality assessment and RevMan5.3 software for statistical analysis. RESULTS: Four articles containing 7 RCTs with 794 participants compared the efficacy of AEDs with placebo. Four RCTs assessed topiramate vs. placebo and 3 RCTs evaluated divalproex sodium extended-release (DVPX ER) vs. placebo. The results demonstrated that children receiving antiepileptic drugs had a significant advantage in remitting the mean monthly migraine days compared to those who received placebo, with an MD of −0.48 (n=930, 95% CI: −0.84 to −0.12, Z=2.60, P=0.009). Topiramate significantly reduced monthly migraine days (MD =−0.70, n=489, 95% CI: −1.16 to −0.25, Z=3.01, P=0.003) but failed to improve the ≥50% response rate (MD =−1.50, n=489, 95% CI: 0.70 to 3.22, Z=1.05, P=0.30). DVPX ER did not significantly reduce monthly headache frequency (n=441, 95% CI: −0.70 to 0.47, Z=0.38, P=0.70) or improve the ≥50% response rate (n=441, 95% CI: 0.59 to 1.25, Z=0.82, P=0.41) compared with placebo. Topiramate and DVPX ER were related to higher rates of side effects and adverse reactions. DISCUSSION: Topiramate can reduce monthly headache days in children and adolescents with migraine. However, it failed to improve the ≥50% response rate. DVPX ER showed no difference from placebo in the prophylactic treatment pediatric migraine. Side effects seemed to be more frequent in topiramate and DVPX ER treated children but generally well-tolerated.

The life of high temperature coating mainly depends on its oxidation resistance and bonding strength with the substrate. SiCnws / SiC coatings were prepared by a self-made two temperature reaction system and chemical vapor deposition method. The oxidation resistance of the composite coating at 900 ℃ and 1500 ℃ and the thermal shock resistance at 1500 ℃ were studied. The fracture toughness and bonding strength of the composite coating were increased by 53.8% and 9.8 times, respectively, due to the stable mechanical linkage effect between the bamboo like SiC nanowires with special nodes and SiC. Due to the healing effect of glass phase SiO2, the weight loss rate of bamboo like SiCnws / SiC coating sample after oxidation at 900 ℃ for 30 h is about 5.28%, and that after isothermal oxidation at 1500 ℃ for 60 h is only 0.74%. In addition, bamboo like SiCnws can effectively alleviate the thermal expansion coefficient mismatch between SiC coating and substrate. After 25 thermal shock cycles, the final oxidation weight loss rate of composite coating is only 2.03%.

The purpose of this study was to investigate the role of voltage-dependent anion channel (VDAC) in mitochondria-mediated apoptosis of neurons in refractory epilepsy. Western blot analyses were carried out to detect the changes in cytochrome C, caspase 9, Bax, and Bcl-2. TUNEL assays were also carried out to investigate cell apoptosis under the upregulation and downregulation of VDAC1 with or without Bax or Bcl-2. VDAC1 induced Bax, Bcl-2, and caspase 9, increasing the release of cytochrome C. VDAC1 played an essential role in the apoptotic cell death of refractory epilepsy. It is concluded that VDAC1 plays an important role in refractory epilepsy and could be a possible therapeutic target of anti-epileptic drugs. The current study provides a new understanding of the possible mechanisms of refractory epilepsy.

The multi-walled carbon nanotubes were prepared into nanopaper with three-dimensional network structure by ultrasonic dispersion technology and suction filtration, and then implanted into Cf / PEEK composite materials by mold pressing process. The microstructure, tensile strength, flexural strength and abrasion resistance of the composites were tested. The influence of the nanopaper on the properties of composites were discussed and analyzed. After implanting a well- dispersed PANI-functionalized nanopaper layer, the tensile strength and bending strength of the 0.1 mm nanopaper composite increased by 20.6% and 26.6% respectively, which meant that high load is needed to cause the composite to break. There are pores in the interface of 0.2 mm nanopaper composite after hot pressing, and the improvement of mechanical properties is not significant. Compared with the pure Cf / PEEK composite, the friction coefficient of 0.1 mm nanopaper composite is reduced by 0.05, and the wear rate is reduced by 26%. This should be ascribed to that the self-lubricating property of MWCNTs. The three-dimensional network structure of nanopaper with good thermal conductivity can disperse the heat generated in the friction process and reduce the contact area between the Si3N4 ball and the resin matrix.

Moyamoya disease (MMD) has a high incidence in Asian populations and demonstrates some degree of familial clustering. Whole-exome sequencing (WES) is useful in establishing key related genes in familial genetic diseases but is time-consuming and costly. Therefore, exploring a new method will be more effective for the diagnosis of MMD. We identified familial cohorts showing MMD susceptibility and performed WES on 5 affected individuals to identify susceptibility loci, which identified point mutation sites in the titin (

Over-application of fertilizers could not improve crop yield and agronomic efficiency, but result in increasing nitrogen (N) surplus and adverse effects on the ecosystem sustainability. Although some previous studies have addressed one or a few environmental aspects in crop production, an integrated assessment for the effects of N fertilizer on multiple environmental impacts, and the optional steps of normalization and weighting is required. A consecutive 2-yr plot-based field experiment was conducted with five N fertilizer levels (0, 90, 180, 270, and 360 kg N ha-1) in maize production at three sites in Southwest China, to evaluate the environmental performance and sustainability through joint use of life cycle assessment (LCA) and energy consumption analysis. Results demonstrated that the optimal N rate (180 kg N ha-1) showed greater potential for maintaining high yield (achieved 86% of the yield potential) and reducing the global warming (-31%), acidification (-47%), eutrophication (-44%) compared to farmers’ practice, and energy depletion potentials, by reducing pollutants emission during the production and transportation of N fertilizer and Nr losses at farm stage. Optimal N treatment indirectly reduced the land use, life-cycle human toxicity, aquatic eco-toxicity, and terrestrial eco-toxicity potentials by improving grain yield and agronomic efficiency. In addition, the optimal N treatment reduced the energy consumption by enhancing the energy use efficiency (EUE) (+74%) and reducing non-renewable energy form (-45%) than the farmer’s practice. This study will provide comprehensive information for both scientists and farmers involved in maize production and N management in subtropical region.

Objective To report a de novo splicing mutation in the CSF1R gene in a patient with hereditary diffuse leukoencephalopathy with spheroids (HDLS). Methods A 42-year-old Chinese woman with constant weakness on her left lower extremity was recruited in the current study. Detail medical history and clinical characteristics were reviewed. Brain magnetic resonance imaging (MRI), whole-exome sequencing, and Sanger sequencing were performed with bioinformatics analysis. Results The Chinese HDLS patient with no HDLS family history exhibited a de novo splicing mutation (c.1754-10 T > A) in the CSF1R gene. This mutation was located at the splice site of intron 12 and resulted in the skipping of exon 13 from the CSF1R mRNA. This finding constitutes the first de novo splicing mutation ever reported in HDLS. Furthermore, MRI abnormalities had been reported at least 6 months prior to the onset of the patient’s clinical phenotype. Conclusion Our study indicates that the diagnosis of HDLS should be considered even in the absence of a family history and can help deepen the clinical and genetic understanding of HDLS.

Small farms are the mainstay of maize production in China. Its productivity is relatively low despite large farm inputs and the associated environmental footprints. Here, we studied public–private partnership (PPP) model for sustainable intensification of maize production to achieve co‐benefits of food security and environmental sustainability. The PPP model enabled the development of an effective partnership by bringing complementary skills, knowledge, proprietary products and technologies, and resources of public research community and private enterprises to create a new, operational maize farming system in China. We conducted on‐farm research with farmer participation in four major maize‐growing regions spanning temperate to sub‐tropical zones in China for 2 years. The PPP model achieved 78.7% of maize yield potential compared with 61.8% realized in smallholder farm (SHF) (11.0 Mg ha−1 vs. 8.6 Mg ha−1). Overall, environmental externalities of PPP were up to 32.7% lower than that of SHF, depending on the region studied. PPP significantly reduced reactive nitrogen losses by 31.3%–35.5% compared with SHF in both years. There was no significant difference between PPP and SHF for greenhouse gas emission in 2018, but it was significantly lower in PPP (19%) compared to SHF in 2019. Similarly, PPP significantly reduced soil acidification potential (by 10.1%–42.2%) and eutrophication of waterbodies (21.5%) in comparison to SHF. Overall, the net ecosystem economic budget increased 277 USD ha−1 with PPP. The PPP model provides new insights into improving food security and ecosystem and economic budget. As a logical progression to our research, future work should focus on (a) the reasons for the persistence of inter‐regional yield gap in PPP model and (b) to gain a better understanding of socioeconomic drivers critical for successful PPP in different maize‐growing regions.

Background: In this study, we aimed to investigate the association between polymorphisms in the RNF213 and MMP3 genes and Moyamoya disease (MMD) and to screen susceptibility genes for families with MMD.Methods: The mutation of RNF213 gene (rs112735431,rs148731719) and MMP3 gene rs3025058 were detected by first generation sequencing and CRISPR-Cas12a. The genetic susceptibility genes of MMD families samples were studied by whole exome sequencing (WES). Results: The application of CRISPR-Cas12a and Sanger sequencing identified rs112735431 and rs148731719 mutations in the RNF213 gene, and an insertion mutation in the MMP3 gene (rs3025058) with significant regional differences (PTTN) gene (rs771533925, rs559712998 and rs72677250) was significantly associated with point mutations. Screening of the Exome Aggregation Consortium (EXAC) database identified significant differences between these populations with respect to frequency. PROVEAN，nvariant Feature Transform (SIFT) and PolyPhen algorithms further demonstrated that rs771533925 and rs72677250 were potentially damaging in three databases, rs559712998 was considered to be tolerated in above mentioned databases. Scale Invariant Feature Transform (SIFT) and PolyPhen algorithms further demonstrated that rs771533925 and rs72677250 were potentially damaging by all three databases and that rs559712998 was considered to be tolerated in above mentioned databases. Gene Ontology (GO) analysis demonstrated that the target of TTN is involved in many important biological processes. The screening of 50 sporadic MMD samples failed to identify any mutations, thus indicating that single nucleotide polymorphism (SNP) mutation sites (rs771533925, rs559712998, and rs72677250) within the TTN gene may play an important role in the inheritance of MMD. Conclusions: In summary, our study investigated susceptibility genes for MMD from multiple perspectives and found that CRISPR-Cas12a technology can efficiently detect MMD mutation sites. Our findings provide a theoretical basis for future investigations of the molecular mechanisms that underlie MMD.

High-performance microwave absorption and being lightweight have become the foremost crucial factors in the practical application of mordern microwave adsorbers. In view of this, we presented the d...

This study investigated the expression and role of immunoproteasome (i-proteasome) in a cell model of Parkinson's disease (PD). The cytotoxicity of rotenone was measured by CCK-8 assay. The i-proteasome β1i subunit PSMB9 was suppressed by a specific shRNA or transfected with an overexpression plasmid in the SH-SY5Y cells. Under the exposure to rotenone or not, the expression of constitutive proteasome β subunits, i-proteasome βi subunits, antigen presentation related proteins, α-syn and TH were detected by Western blot in PSMB9-silenced or -overexpressed cells, and the proteasomal activities were detected by fluorogenic peptide substrates. The location of i-proteasome βi subunits and α-syn were detected by immunofluorescence staining. The levels of ROS, GSH and MDA were measured by commercial kits. Cell apoptosis was detected by flow cytometry. Besides impairing the constitutive proteasomes, rotenone induced the expression of βi subunits of i-proteasome and antigen presentation related proteins such as TAP1, TAP2 and MHC-I. Silencing or overexpressing PSMB9 had no obvious effect on the levels of other subunits, but could regulate the chymotrypsin-like activity of 20S proteasome and the expression of TAP1, TAP2 and MHC-I. Three βi subunits (PSMB9, PSMB10, PSMB8) of i-proteasome were all co-localized with α-syn. PSMB9 knockdown aggravated accumulation of α-syn, degradation of TH, release of ROS, increased level of MDA, decreased level of GSH and eventually promoted apoptosis in SH-SY5Y cells after rotenone treatment, while over-expression of PSMB9 could attenuate these toxic effects of rotenone. I-proteasome is activated in SH-SY5Y cells treated with rotenone and may play a neuroprotective role.

While the relationship between crop yields and the environmental impacts of crop agriculture has been well‐documented, research on the relationship between farm size and the sustainability of cereal production is limited. Using survey data on 120 farms with both small‐ and large‐scale fields in Northeast China, this paper combines a life cycle assessment and the carbon‐based sustainability index (SI) algorithm to examine how maize productivity and agricultural inputs vary with farm size and to clarify how increasing farm size is correlated with energy use efficiency (EUE) and the SI. The results indicate that maize grain yield did not vary with farm size. Increasing farm size was shown to lead to reductions in the areal (per ha) rates of agro‐chemical inputs, energy depletion, and greenhouse gas emissions and increased in EUE and SI. Fertilizer‐ and fuel‐related agricultural inputs dominated the variations of EUE and SI. A scenario analysis indicates that, if farmers adopt a comprehensive management strategy (i.e., machines appropriate to farm size and recommended fertilizer application rates and crop management strategies), EUE and SI would increase by 68.5% (from 4.45 to 7.50) and 74.3% (from 10.1 to 17.6), respectively. Although increasing farm size could benefit maize sustainable production when matched with technical innovation and machinery coordination, supporting smallholder farmers to increase their resource use efficiency and sustainability is also key in China and other regions where smallholder farms comprise a large portion of the cropland area.

Background: Migraine is the most common acute primary headache in children and adolescents. In 2014, topiramate became the first preventive drug for migraine, approved by the Food and Drug Administration (FDA) for adolescents. This meta-analysis was aimed to evaluate the efficacy and safety of topiramate in the prevention of pediatric migraine.Methods: We searched the PubMed, EMBASE, Cochrane Library, and Chinese National Knowledge Infrastructure (CNKI) databases up to June 2019 for eligible randomized controlled trials (RCTs). The primary outcomes were mean migraine days per month, ≥50% reduction rate, and Pediatric Migraine Disability Assessment Scale (PedMIDAS) scores. RevMan5.3 software was performed for statistical analysis.Results: Overall, 5 RCTs recruiting 531 patients (6–17 years of age) were included in the meta-analysis. The target dose of topiramate was 2 mg/kg (the maintenance phase was 12 weeks), 2–3 mg/kg, 50 mg/day, and 100 mg/day (maintaining for 16 weeks), respectively, in the included studies. Our results demonstrate that participants receiving topiramate had a significant advantage in remitting the monthly migraine days than those receiving placebo, with a mean difference (MD) of −0.78 (n = 531; 95% CI, −1.23 to −0.32; Z = 3.37; P = 0.0008). Topiramate could also reduce the mean PedMIDAS scores (n = 238; 95% CI, −16.53 to −0.49; Z = 2.43; P = 0.04). However, there was no significant difference in the percentage of patients experiencing a ≥50% reduction in monthly headache days between topiramate and placebo groups (n = 531; 95% CI, 0.94–1.77; Z = 1.58; P = 0.11). Topiramate was associated with higher rates of side effects such as weight decrease (n = 395; 95% CI, 2.73–22.98; Z = 3.81; P < 0.01) and paresthesia (n = 531; 95% CI, 3.05–13.18; Z = 4.94; P < 0.01).Conclusions: Topiramate can significantly decrease monthly headache days and migraine-related burden in migraine patients

Effective fertilizer nitrogen (N) management plays an important role in reducing the environmental problems caused by its overuse in maize production systems. The use of enhanced-efficiency N fertilizers is an effective approach to increase crop productivity and N use efficiency. However, to the best of our knowledge, there have been no associated comprehensive evaluations of the environmental impacts using a life cycle assessment (LCA) and ecosystem economic benefits (EEB). In this study, a consecutive 2-yr plot-based field experiment was conducted in Southwest China with two N fertilizer sources, blended urea (BU) containing controlled-release urea and conventional urea (CU) at a 1:1 ratio and CU only at five N rates (0, 90, 180, 270, and 360 kg N ha−1) to determine the agronomic and environmental benefits as well as the EEB of BU in maize production. The results showed that among the five N rates tested, the N180 treatment (180 kg N ha−1) showed greater potential for maintaining a high yield (8.8 Mg ha−1) and reducing environmental impacts. The use of BU resulted in higher grain yield and agronomic efficiency compared to those with CU at 180 kg N ha−1 in 2018 but not in the following year. In addition, BU significantly reduced reactive nitrogen losses through nitrous oxide emission (−27%), ammonia volatilization (−18%), and N leaching (−24%), reducing the crop environmental footprint by decreasing the global warming, acidification, and eutrophication potential by 8%–13%, 4%–9%, and 8%–22%, respectively. Furthermore, the use of BU increased economic benefits and EEB by reducing agricultural (N fertilizer; labour) and ecological costs. Compared to CU, BU improved the EEB by 68%, 39%, 29%, and 25% at N rates of 90, 180, 270, and 360 kg N ha−1, respectively. These results demonstrated that replacement of CU with BU at the N rate of 180 kg N ha−1 is an effective strategy to improve sustainability of maize production in subtropical regions of China.

The present study described the characteristics of three cases of Creutzfeldt-Jakob disease (CJD) in China and analyzed their clinical presentations. The clinical information of the three cases was collected and analyzed. Blood and cerebrospinal fluid (CSF) specimens of the patients were collected for detection of the prion protein (PRNP) gene and 14–3-3 protein levels. Dynamic changes of electroencephalograms (EEGs) and brain magnetic resonance images (MRIs) were also observed. All the three cases were sporadic CJD cases. They presented with symptoms including hyposthenia, progressive memory loss, truncal and limb ataxia, dysarthria, lowered vision acuity, bucking, language disorders, myoclonia and akinetic mutism state. One of the three cases was associated with a prolonged duration of >6 years. The EEG of two cases showed slow biphasic waves. The diffusion-weighted MRI sequence revealed abnormal hyperintensity and bilateral ribboning in the cortex. Two patients tested positive for the 14–3-3 protein in the CSF. All patients were of methionine homozygosity at codon 129 in the gene encoding PRNP protein and one patient had a mutation. The CJD cases showed differences in terms of symptoms and disease duration. Subacute onset was common and with attentive nursing and supportive treatments, one of the patients had a prolonged survival time of >6 years.

BackgroundNon-motor symptoms are common in Parkinson’s disease (PD) and can even be used as part of the supportive criteria for diagnosis. Chronic inflammation is involved in every stage of PD. Disorders of the immune system affect the peripheral blood. Whether the humoral immune response is associated with the non-motor symptoms of PD remains unknown.MethodsMann–Whitney tests and Bonferroni correction were used to compare the serum levels of IgG, IgA, IgM, C3, and C4 between 180 sporadic PD patients and 187 healthy controls. Multiple regression models were conducted to assess the associations among these indicators of humoral immunity and the clinical features of PD patients.ResultsMale PD patients had lower levels of C3 and C4 than healthy controls [0.87 (0.22) vs. 0.96 (0.19); 0.19 (0.06) vs. 0.22 (0.07), respectively, Pc < 0.01] and lower levels of C3 than female PD patients [0.87 (0.22) vs. 1.02 (0.23), Pc < 0.01]. Patients suffering from attention/memory problems had significantly lower levels of IgA and C3 than those without these problems [1.92 (1.21) vs. 2.57 (0.76); 0.89 (0.24) vs. 0.97 (0.24), respectively, Pc < 0.04]. In addition, serum IgG levels were negatively associated with mood/cognition problem scores and were positively associated with gastrointestinal tract problem scores (adjusted R2 = 0.063, F = 1.805, p = 0.038). Serum C3 levels were negatively associated with being male, age, and sleep/fatigue problem scores (adjusted R2 = 0.123, F = 2.678, p = 0.001).ConclusionThe peripheral humoral immune response might be correlated with the non-motor symptoms of PD.

Background Gut microbiota has been suggested to play a role in stroke patients. Nevertheless, little is known about gut microbiota and the clinical indexes in stroke patients. Methods Total of 30 cerebral ischemic stroke (CI) patients and 30 healthy control were enrolled in this study and the fecal gut microbiota was profiled via Illumina sequencing of the 16S rRNA V1-V2. The National Institutes of Health Stroke Scale (NIHSS) were used to quantify stroke severity and modified Rankin scale (mRS) to assess outcome for CI patients. The correlations between the clinical indexes and microbiota were evaluated. Results Though the microbial α-diversity and structure is similar between CI patients and healthy controls, the gut microbiota of CI patients had more short chain fatty acids producer including Odoribacter, Akkermansia, Ruminococcaceae_UCG_005 and Victivallis. We also found that the special microbes were correlation with serum index, such as norank_O_ _Mollicutes_RF9, Enterobacter, Ruminococcaceae_UCG-002 were negative correlation with LDL (r = − 0.401, P

Table S1. The serum index of CI patient and healthy control. (PDF 140 kb)

Subacute combined degeneration (SCD) is a relatively rare myelopathy mainly caused by vitamin B12 (VitB12) deficiency. There are many causes contributing to VitB12 deficiency. Autoimmune gastritis might lead to severe VitB12 malabsorption and in its advanced stage pernicious anemia (PA) may occur. Besides, long-term hypergastrinemia arising from achlorhydria in autoimmune gastritis is associated with neuroendocrine tumors (NETs). Patients diagnosed with SCD coexistent with PA and NET are seldomly reported. We describe a 34-year-old woman with an initial complaint of progressive fatigue, weakness and numbness in her limbs and disturbed gait. Physical examination revealed appearance of anemia, ataxia, decrease of superficial and deep sense, and positive Babinski's sign. Laboratory tests disclosed macrocytic anemia, elevated intrinsic factor antibody and spinal MRI showed extensive T2-weighted hyperintensity in the dorsal columns. A gastric polyp was revealed by gastroscopy and histology showed an NET in the background of severe atrophic gastritis. Symptoms of the patient were relieved by a multidisciplinary therapy. In patients with SCD, PA should be suspected and prompt further investigations to elucidate causes and direct treatment.

Table S2. The severity and outcome of CI patients. (PDF 107 kb)

Esophageal squamous cell carcinoma (ESCC) is the sixth leading cause of death due to cancer, indicating that finding new therapeutic targets or approaches for ESCC treatment is imperative. Transient Receptor Potential cation channel subfamily M, member 2 (TRPM2) is a calcium-permeable, nonselective cation channel that responds to reactive oxygen species (ROS), which are found in the tumor microenvironment and are important regulators of tumorigenesis, cell proliferation, apoptosis, and the therapeutic response. Here, we used immunohistochemical analysis of tumor tissue derived from patients with ESCC to find that the TRPM2 channel protein expression level was increased in tumor tissue compared with adjacent normal tissue. Intracellular calcium concentration measurements, western blotting, and ROS and cell viability assays were used with a human ESCC cell line (TE-1 cells) to find that TRPM2 participated in the ROS hydrogen peroxide-induced increase in intracellular calcium. This increased calcium inhibited cell proliferation and enhanced apoptosis. Pretreatment of cells with the anticancer agent 5-fluorouracil (5-FU) significantly increased ROS production, which potentiated TRPM2-mediated calcium signaling, decreased cell proliferation, and increased apoptosis in TE-1 cells, suggesting that the therapeutic effect of 5-FU in ESCC cells may be mediated by the TRPM2 channel-mediated calcium influx. These findings offer a potential treatment target and provide mechanistic insight into the therapeutic effects of 5-FU in patients with ESCC.

The study was to investigate whether immunoproteasome (i-proteasome) and its downstream pathway are related to the pathogenesis of Parkinson's disease (PD). Rats were treated with rotenone showed significant weight loss and dyskinesia, which is consistent with the degeneration of TH-positive neurons and the activation of Iba-1-positive microglia/macrophages. Two major catalytic subunits of i-proteasome (PSMB9 and PSMB8) were seldom expressed in rat substantia nigra (SN) under normal condition, but they were significantly up-regulated with the release of TNF-α and IFN-γ after exposure to rotenone. In addition, compared with control group, the antigen presentation-related proteins antigen peptide transporter (TAP) 1, TAP2, major histocompatibility complex (MHC)-I and MHC-II levels were significantly up-regulated in rotenone group, which was in line with the accumulation of α-syn. These findings suggested that i-proteasome and antigen presentation pathways (related proteins) were upregulated by rotenone in a PD rat model.

The novel hierarchical SiC nanowire-reinforced SiC/carbon foam composites (SnwSCF) were prepared for the first time by carbonization, CVD, and CVI processes. Morphological results demonstrated that the hierarchical structure, composed of carbon foam with a SiC coating and SiC nanowires, was fabricated successfully. The hierarchical structure significantly improved the microwave-absorbing performance of the carbon foam. The optimal reflection loss value of SnwSCF achieved −31.216 dB at 15.76 GHz with a 1.5 mm absorber thickness. The corresponding effective absorption bandwidth was 4.1 GHz. Furthermore, the microwave-absorption mechanism of SnwSCF is discussed in depth. The incident EM waves were trapped in the hierarchical structure and experienced multiple microwave energy attenuation processes including multiple reflections, interface polarization, and dipole polarization. As a result, SnwSCF is believed to be a superior candidate to its competitors as an ultralight, ultrathin, and highly efficient microwave absorber.

In this work, we prepared the bamboo-like SiC nanowires reinforced SiC coating and studied the frictional wear properties under low applied load (6 N) and high applied load (30 N), aiming to enhance the wear resistance of the pure SiC coating. After introducing bamboo-like SiC nanowires, the fracture toughness and bonding strength of the composite coating were increased by 63.18% and 9.9 times, respectively, which meaned that high load was needed to cause the coating to break. Under the applied load of 6 N, the wear extents of both the pure SiC coating and the composite coating were relatively low, but the high hardness of the composite coating made the wear even lower. As the applied load increased to 30 N, the wear rate of the pure SiC coating was 0.217%, while that of the composite coating was just 0.043%. This should be ascribed to that the improved fracture toughness could hinder brittle fracture and grain extraction, and the bamboo-like SiC nanowires could absorb a great deal of fracture energy.

To design a lightweight and high-performance absorber, this work introduced a novel three-dimensional interconnected SiC foam with double-layer hollow skeleton (3D-ISF), which was prepared by depositing SiC, pyrolytic carbon, and SiC layer on interconnected carbon foam, followed by oxidation of carbon. SEM results showed the interconnected hollow structure had been successfully synthesized, which was beneficial for microwave absorbing efficiency, and numerous columnar SiC defects were observed and played a critical role in the microwave absorption properties. The electromagnetic performances of 3D-ISF-I and 3D-ISF-II were investigated in depth. With the increase of thickness of SiC layer, 3D-ISF-II exhibited a better microwave absorption property, which could be ascribed to the higher impedance matching ratio (Z r ) and attenuation constant (α). The optimum reflection loss value of 3D-ISF-II could reach −45.649 dB while that of 3D-ISF-I was just −32.070 dB. There is no doubt that the prepared materials have tunable microwave absorbing properties, which can promote the development of SiC-based absorbing materials to a certain extent. Finally, it was confirmed that the Z r played a dominant role in 3D-ISF, which provided practical guidance for the design of porous materials.