Construction of the single-diamond-structured titania scaffold-Recreation of the holy grail photonic structure.

As one of the most stunning biological nanostructures, the single-diamond (SD) surface discovered in beetles and weevils exoskeletons possesses the widest complete photonic bandgap known to date and is renowned as the "holy grail" of photonic materials. However, the synthesis of SD is difficult due to its thermodynamical instability compared to the energetically favoured bicontinuous double diamond and other easily formed lattices; thus, the artificial fabrication of SD has long been a formidable challenge. Herein, we report a bottom-up approach to fabricate SD titania networks via a one-pot cooperative assembly scenario employing the diblock copolymer poly(ethylene oxide)-block-polystyrene as a soft template and titanium diisopropoxide bis(acetylacetonate) as an inorganic precursor in a mixed solvent, in which the SD scaffold was obtained by kinetically controlled nucleation and growth in the skeletal channels of the diamond minimal surface formed by the polymer matrix. Electron crystallography investigations revealed the formation of tetrahedrally connected SD frameworks with the space group Fd [Formula: see text] m in a polycrystalline anatase form. A photonic bandgap calculation showed that the resulting SD structure has a wide and complete bandgap. This work solves the complex synthetic enigmas and offers a frontier in hyperbolic surfaces, biorelevant materials, next-generation optical devices, etc.

Changes of neuroplasticity in cortical motor control of human masseter muscle related to orthodontic treatment.

BACKGROUND: Orthodontic treatment is a common clinical method of malocclusion. Studies have found that neurons in the sensorimotor cortex of the brain undergo adaptive remodeling in response to changes in oral behavior or occlusion. OBJECTIVE: To explore whether orthodontic treatment could be sufficient to cause neuroplastic changes in the corticomotor excitability of the masseter muscle. METHODS: Fifteen Angle Class II malocclusion patients who were receiving orthodontic treatment participated in the study. Cortical excitability was assessed by electromyographic activity changes evoked by transcranial magnetic stimulation. Four orthodontic time points were recorded, including baseline, day 1, day 7, and day 30. Motor evoked potentials (MEPs) were recorded in the masseter muscle and the first dorsal interosseous muscle (FDI) serving as a control. The data were analysed by stimulus-response curves and corticomotor mapping. Statistical analyses involved repeated measures analysis of variance, two-way ANOVA, and Tukey's post hoc tests. RESULTS: Motor evoked potentials (MEPs) of the masseter muscle were significantly decreased during orthodontic treatment compared with those of the baseline (p < .001). MEPs of the masseter muscle were dependent on session and stimulus intensity (p < .001), whereas MEPs of FDI were only dependent on stimulus intensity (p = .091). Finally, Tukey's post hoc tests demonstrated that MEPs of the masseter muscle on days 1 and 7, with 70%-90% stimulus intensities, were higher than those of baseline values (p < .001). CONCLUSIONS: The present study suggested that orthodontic treatment can lead to neuroplastic changes in the corticomotor control of the masseter muscle, which may add to our understanding of the adaptive response of subjects to changes of oral environment during the orthodontic treatment.

Self-Assembly of Single-Diamond-Surface Networks.

Biological scaffolds with hyperbolic surfaces, especially single gyroid and single-diamond structures, have sparked immense interest for creating novel materials due to their extraordinary physical properties. However, the ability of nature to create these unbalanced surfaces has not been achieved in either lyotropic liquid crystals or block copolymer phases due to their thermodynamical instability in these systems. Here, we report the synthesis of a porous silica scaffold with a single-diamond-surface structure fabricated by self-assembly of the poly(ethylene oxide)-b-polystyrene-b-poly(L-lactide) and silica precursors in a mixed solvent of tetrahydrofuran and water. The single-diamond structure with tetrahedral interconnected frameworks was revealed by the electron crystallographic reconstruction. We assume that the formation of single networks is induced by the structural transition and related to the energetic change due to the fluctuations of the Gaussian curvature. This work may provide new insights into these biologically relevant surfaces and related self-assembly systems.

ZIPK mediates endothelial cell contraction through myosin light chain phosphorylation and is required for ischemic-reperfusion injury.

The paracellular gap formed by endothelial cell (EC) contraction is fundamental for endothelium permeability, but the mechanism underlying EC contraction has yet to be determined. Here, we identified the zipper-interacting protein kinase (ZIPK) as the kinase for EC contraction and myosin light chain (MLC) phosphorylation. Inhibition of ZIPK activity by pharmacological inhibitors and small interfering RNAs led to a significant decrease in the mono- and diphosphorylation of MLCs along with a contractile response to thrombin, suggesting an essential role of ZIPK in EC paracellular permeability. To assess the role of ZIPK in vivo, we established mouse lines with conditional deletion of Zipk gene. The endothelium-specific deletion of Zipk led to embryonic lethality, whereas the UBC-CreERT2-mediated deletion of Zipk by tamoxifen induction at adulthood caused no apparent phenotype. The induced deletion of Zipk significantly inhibited ischemia-reperfusion-induced blood-brain barrier dysfunction and neuronal injuries from middle cerebral artery occlusion and reperfusion, as evidenced by reduced infarct and edema volume, attenuated Evans blue dye leakage, and improved neuronal behavior. We thus concluded that ZIPK and its phosphorylation of MLC were required for EC contraction and ischemic neuronal injuries. ZIPK may be a prospective therapeutic target for stroke.-Zhang, Y., Zhang, C., Zhang, H., Zeng, W., Li, S., Chen, C., Song, X., Sun, J., Sun, Z., Cui, C., Cao, X., Zheng, L., Wang, P., Zhao, W., Zhang, Z., Xu, Y., Zhu, M., Chen, H. ZIPK mediates endothelial cell contraction through myosin light chain phosphorylation and is required for ischemic-reperfusion injury.

Jatrorrhizine Hydrochloride Suppresses Proliferation, Migration, and Secretion of Synoviocytes In Vitro and Ameliorates Rat Models of Rheumatoid Arthritis In Vivo.

Jatrorrhizine hydrochloride (JH), an active component isolated from the traditional Chinese herb Coptis chinensis, has been reported to have antimicrobial, antitumor, antihypercholesterolemic, and neuroprotective activities. However, its antirheumatoid arthritis (RA) property remains unknown. In this study, a collagen-induced arthritis (CIA) rat model was used to evaluate the therapeutic effects of JH on RA by using arthritis score, radiological evaluation, and histopathological assessment. The in vitro effects of JH on proliferation, migration, and production of inflammatory mediators in RA-derived fibroblast-like synoviocyte MH7A cells were determined by the EdU incorporation assay, wound healing assay, real-time PCR, and ELISA, respectively. The in vivo studies showed that JH treatment significantly prevented the progression and development of RA in CIA rats through anti-inflammation and suppressing bone destruction. The in vitro studies revealed that JH could effectively attenuate the destructive phenotypes of MH7A cells, including inhibiting proliferation, migration, and production of inflammatory mediators. Further mechanistic analysis demonstrated that JH suppressed tumor necrosis factor alpha (TNFα)-stimulated activations of nuclear factor of kappaB (NF-κB) and mitogen-activated protein kinases (MAPKs) (ERK and p38) leading to the downregulation of proinflammatory cytokines, which might be beneficial to the antiproliferative and antimigratory activities of FLS cells. Collectively, our results demonstrated that JH has a great potential to be developed into a novel therapeutic agent for treating RA.

Strain-Specific Benefits of Bacillus on Growth, Intestinal Health, Immune Modulation, and Ammonia-Nitrogen Stress Resilience in Hybrid Grouper.

In the dynamic field of intensive aquaculture, the strategic application of probiotics has become increasingly crucial, particularly for enhancing resistance to environmental stressors such as ammonia-nitrogen. Over a 42-day period, this study investigated the effects of different probiotic strains-Bacillus subtilis (BS, 6-3-1, and HAINUP40)-on the health and resilience of hybrid groupers. Each strain, distinct in its origin, was assessed for its influence on growth performance, antioxidant capacity, immune gene expressions, and ammonia-nitrogen stress response in the hybrid grouper. The experimental design included a control group and three experimental groups, each supplemented with 1 × 108 CFU/g of the respective probiotic strains, respectively. Our results demonstrated notable differences in growth parameters, including final body weight (FBW) and feed conversion ratio (FCR). The 6-3-1 strain, originating from grouper, exhibited significant improvements in growth, oxidative capacity, and intestinal health. Conversely, the BS strain achieved the highest survival rates under ammonia-nitrogen stress, indicating its superior ability to regulate inflammatory responses despite its less pronounced growth-promoting effects. The HAINUP40 strain was distinguished for its growth enhancement and improvements in intestinal health, though it also showed significant activation of inflammatory genes and decreased resistance to ammonia-nitrogen stress after extended feeding. The uniqueness of this study lies in its detailed examination of the strain-specific effects of probiotics on fish in the context of ammonia-nitrogen stress, a significant challenge in contemporary aquaculture. The research revealed that host-derived probiotics, particularly the 6-3-1 strain, provided more comprehensive benefits for growth performance and stress resilience. In contrast, the BS and HAINUP40 strains exhibited varying efficiencies, with BS excelling in stress resistance and HAINUP40 promoting growth and gut health. In conclusion, this study underscores the complex roles of different probiotic strains in aquaculture, contributing to the understanding of probiotic applications and presenting new approaches to address the challenges of intensive farming.

CXCL4/CXCR3 axis regulates cardiac fibrosis by activating TGF-ß1/Smad2/3 signaling in mouse viral myocarditis.

BACKGROUND: Severe myocarditis is often accompanied by cardiac fibrosis, but the underlying mechanism has not been fully elucidated. CXCL4 is a chemokine that has been reported to have pro-inflammatory and profibrotic functions. The exact role of CXCL4 in cardiac fibrosis remains unclear. METHODS: Viral myocarditis (VMC) models were induced by intraperitoneal injection of Coxsackie B Type 3 (CVB3). In vivo, CVB3 (100 TCID50) and CVB3-AMG487 (CVB3: 100 TCID50; AMG487: 5 mg/kg) combination were administered in the VMC and VMC+AMG487 groups, respectively. Hematoxylin and eosin staining, severity score, Masson staining, and immunofluorescence staining were performed to measure myocardial morphology in VMC. Enzyme-linked immunosorbent assay (ELISA) and quantitative reverse transcription polymerase chain reaction (qRT-PCR) were performed to quantify inflammatory factors (IL-1ß, IL-6, TNF-α, and CXCL4). Aspartate aminotransferase (AST), lactate dehydrogenase (LDH), and creatine kinase-myocardial band (CK-MB) levels were analyzed by commercial kits. CXCL4, CXCR3B, α-SMA, TGF-ß1, Collagen I, and Collagen III were determined by Western blot and immunofluorescence staining. RESULTS: In vivo, CVB3-AMG487 reduced cardiac injury, α-SMA, Collagen I and Collagen III levels, and collagen deposition in VMC+AMG487 group. Additionally, compared with VMC group, VMC+AMG group decreased the levels of inflammatory factors (IL-1ß, IL-6, and TNF-α). In vitro, CXCL4/CXCR3B axis activation TGF-ß1/Smad2/3 pathway promote mice cardiac fibroblasts differentiation. CONCLUSION: CXCL4 acts as a profibrotic factor in TGF-ß1/Smad2/3 pathway-induced cardiac fibroblast activation and ECM synthesis, and eventually progresses to cardiac fibrosis. Therefore, our findings revealed the role of CXCL4 in VMC and unveiled its underlying mechanism. CXCL4 appears to be a potential target for the treatment of VMC.

Nitrogen-doped carbon dots as fluorescent probes for sensitive and selective determination of Fe3.

At present, the contamination of water resources by heavy metal ions has posed a significant threat to human survival. Therefore, it is particularly critical to develop low-cost, easy-to-use, and highly efficient heavy metal detection technologies. In this work, a fast and cost-effective fluorescent probe for nitrogen-doped carbon dots (N-CDs) was prepared using one-step hydrothermal method with citric acid (CA) as carbon source, and melamine as nitrogen source. The structural and optical characterizations of the resulting N-CDs were investigated in details. The results showed that the quantum yield of the prepared fluorescent probe was as high as 45 %, and an average fluorescence lifetime was about 7.80 ns. N-CDs have excellent water solubility and dispersibility, with an average size of 2.58 nm. N-CDs exhibited excellent specific responsiveness to Fe3+ and can be used as an effective method for detecting Fe3+ at low-concentrations (the concentrations of N-CDs as low as 0.24 µg/mL) using fluorescent probes. The linear response of the fluorescent probe N-CDs to Fe3+ was formed in the concentration range of 20-80 µM, and the detection limit was 3.18 µM. In addition, in the actual water samples analysis, the recovery rate reached 97.05-100.58 %. The prepared of N-CDs provide available Fe3+ fluorescent probes in the environment.

Strain-Specific Benefits of Bacillus Probiotics in Hybrid Grouper: Growth Enhancement, Metabolic Health, Immune Modulation, and Vibrio harveyi Resistance.

In the realm of modern aquaculture, the utilization of probiotics has gained prominence, primarily due to their ability to enhance growth, boost immunity, and prevent diseases in aquatic species. This study primarily investigates the efficacy of Bacillus subtilis strains, both host-derived and from other sources, in influencing fish growth, immunity, lipid metabolism, and disease resistance. Employing a 42-day feeding trial, we divided hybrid grouper into four distinct groups: a control group on a basal diet and three experimental groups supplemented with 1 × 108 CFU/g of different Bacillus subtilis strains-BS, 6-3-1, and HAINUP40. Remarkably, the study demonstrated that the 6-3-1 and HAINUP40 groups exhibited significant enhancements across key growth parameters: final body weight (FBW), weight gain rate (WGR), feed intake (FI), feed efficiency ratio (FER), and feed conversion ratio (FCR). The investigation into lipid metabolism revealed that the 6-3-1 strain upregulated seven metabolism-related genes, HAINUP40 affected four metabolism-related genes, and the BS strain influenced two metabolism-related genes, indicating diverse metabolic impacts by different strains. Further, a notable reduction in liver enzymes AST and ALT was observed across all supplemented groups, implying improved liver health. Noteworthy was the BS strain's superior antioxidative capabilities, positively affecting all four measured parameters (CAT, GSH-Px, MDA). In the sphere of immune-related gene expression, the BS strain significantly decreased the expression of both inflammation and apoptosis-related genes, whereas the HAINUP40 strain demonstrated an upregulation in these genes. The challenge test results were particularly telling, showcasing improved survival rates against Vibrio harveyi infection in the BS and 6-3-1 groups, unlike the HAINUP40 group. These outcomes highlight the strain-specific nature of probiotics and their varying mechanisms of action within the host. In conclusion, this study reveals that probiotic strains, varying by source, demonstrate unique, strain-specific effects in promoting growth and modulating immunity in hybrid grouper. This research highlights the promise of tailored probiotic applications in improving aquaculture practices. Such advancements contribute to more sustainable and efficient fish farming methods.

Toward Ultrahigh Rate and Cycling Performance of Cathode Materials of Sodium Ion Battery by Introducing a Bicontinuous Porous Structure.

The emerging sodium-ion batteries (SIBs) are one of the most promising candidates expected to complement lithium-ion batteries and diversify the battery market. However, the exploitation of cathode materials with high-rate performance and long-cycle stability for SIBs has remained one of the major challenges. To this end, an efficient approach to enhance rate and cycling performance by introducing an ordered bicontinuous porous structure into cathode materials of SIBs is demonstrated. Prussian blue analogues (PBAs) are selected because they are recognized as a type of most promising SIB cathode materials. Thanks to the presence of 3D continuous channels enabling fast Na+ ions diffusion as well as the intrinsic mechanical stability of bicontinuous architecture, the resultant PBAs exhibit excellent rate capability (80 mAh g-1 at 2.5 A g-1) and ultralong cycling life (>3000 circulations at 0.5 A g-1), reaching the top performance of the reported PBA-based cathode materials. This study opens a new avenue for boosting sluggish ion diffusion kinetics in electrodes of rechargeable batteries and also provides a new paradigm for solving the dilemma that electrodes' failure due to high-stress concentration upon ion storage.

Amino acids as methyl donors for the formation of N,N-dimethylpiperidinium (mepiquat) in model systems and cooked mushrooms.

In the present study, new methylating agents for the formation of N,N-dimethylpiperidinium (mepiquat) were evaluated in both model and mushroom systems. Mepiquat levels were monitored using five model systems; alanine (Ala)/pipecolic acid (PipAc), methionine (Met)/PipAc, valine (Val)/PipAc, leucine (Leu)/PipAc, and isoleucine (Ile)/PipAc. The highest level of mepiquat was 1.97% at 260 °C for 60 min (Met/PipAc model system). Piperidine can actively combine with methyl groups in thermal reactions to form N-methylpiperidine and mepiquat. Additionally, mushrooms rich in amino acids were oven baked, pan cooked, and deep fried, respectively, to investigate the formation of mepiquat. Oven baking led to the highest mepiquat content of 63.22 ± 0.88 µg/kg. In summary, food constituents are the main source of precursors for mepiquat formation, the mechanism of which has been presented in both model systems and mushroom matrices rich in amino acids.

Trx CDSP32-overexpressing tobacco plants improves cadmium tolerance by modulating antioxidant mechanism.

The effects of overexpression of the thioredoxin-like protein CDSP32 (Trx CDSP32) on reactive oxygen species (ROS) metabolism in tobacco leaves exposed to cadmium (Cd) were studied by combining physiological measures and proteomics technology. Thus, the number of differentially expressed proteins (DEPs) in plants overexpressing the Trx CDSP32 gene in tobacco (OE) was observed to be evidently lower than that in wild-type (WT) tobacco under Cd exposure, especially the number of down-regulated DEPs. Cd exposure induced disordered ROS metabolism in tobacco leaves. Although Cd exposure inhibited the activities of superoxide dismutase (SOD), catalase (CAT), and l-ascorbate peroxidase (APX) and the expression of proteins related to the thioredoxin-peroxiredoxin (Trx-Prx) pathway, the increase in the activities of peroxidase (POD), monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), glutathione reductase (GR), glutathione peroxidase (GPX), and glutathione S-transferase (GST) and their protein expression levels played an important role in the physiological response to Cd exposure. Notably, Trx CDSP32 was observed to alleviate the decrease in the expression and activities of SOD and CAT caused by Cd exposure and enhance the function of POD. Trx CDSP32 was observed to increase the H2O2 scavenging capacity of the ascorbic acid-glutathione (AsA-GSH) cycle and Trx-Prx pathway under Cd exposure, and it can especially regulate 2-Cys peroxiredoxin (2-Cys Prx) protein expression and thioredoxin peroxidase (TPX) activity. Thus, overexpression of the Trx CDSP32 gene can alleviate the oxidative damage that occurs in tobacco leaves under Cd exposure by modulating antioxidant defense systems.

Triggering Pt Active Sites in Basal Plane of Van der Waals PtTe2 Materials by Amorphization Engineering for Hydrogen Evolution.

Exposing active sites and optimizing their binding strength to reaction intermediates are two essential strategies to significantly improve the catalytic performance of 2D materials. However, pursuing an efficient way to achieve these goals simultaneously remains a considerable challenge. Here, using 2D PtTe2 van der Waals material with a well-defined crystal structure and atomically thin thickness as a model catalyst, it is observed that a moderate calcination strategy can promote the structural transformation of 2D crystal PtTe2 nanosheets (c-PtTe2 NSs) into oxygen-doped 2D amorphous PtTe2 NSs (a-PtTe2 NSs). The experimental and theoretical investigations cooperatively reveal that oxygen dopants can break the inherent Pt-Te covalent bond in c-PtTe2 NSs, thereby triggering the reconfiguration of interlayer Pt atoms and exposing them thoroughly. Meanwhile, the structural transformation can effectively tailor the electronic properties (e.g., the density of state near the Fermi level, d-band center, and conductivity) of Pt active sites via the hybridization of Pt 5d orbitals and O 2p orbitals. As a result, a-PtTe2 NSs with large amounts of exposed Pt active sites and optimized binding strength to hydrogen intermediates exhibit excellent activity and stability in hydrogen evolution reaction.

Heterologous expression of Zygophyllum xanthoxylon zinc finger protein gene (ZxZF) enhances the tolerance of poplar photosynthetic function to drought stress.

The ZxZF transcription factor (TF) of Zygophyllum xanthoxylon (Bunge) Maxim, an extremely drought-resistant woody plant, is a C2H2 zinc finger protein. Studies have shown that C2H2 zinc finger proteins play important roles in activating stress-related genes and enhancing plant resistance. However, their function in regulating plant photosynthesis under drought stress is not well understood. Since poplar is an important greening and afforestation tree species, it is particularly important to cultivate excellent drought-tolerant varieties. The ZxZF transcription factor (TF) was heterogeneously expressed in Euroamerican poplar (Populus × euroameracana cl.'Bofengl') by genetic transformation. Based on the mechanism and potential function of poplar photosynthesis regulated by ZxZF under drought stress, transcriptomic and physiological determinations were used to reveal the important role of this gene in improving the drought resistance of poplar. The results showed that the overexpression of ZxZF TF in transgenic poplars could improve the inhibition of Calvin cycle by regulating stomatal opening and increasing the concentration of intercellular CO2. The chlorophyll content, photosynthetic performance index, and photochemical efficiency of transgenic lines under drought stress were significantly higher than those of the wild type (WT). The overexpression of ZxZF TFs could alleviate the degree of photoinhibition of photosystems II and I under drought stress and maintain the efficiency of light energy capture and the photosynthetic electron transport chain. The transcriptomic data also showed that differentially expressed genes between the transgenic poplar and WT under drought stress were primarily enriched in metabolic pathways related to photosynthesis, such as photosynthesis, photosynthesis-antenna protein, porphyrin and chlorophyll metabolism, and photosynthetic carbon fixation, and the downregulation of genes related to chlorophyll synthesis, photosynthetic electron transport and Calvin cycle were alleviated. In addition, the overexpression of ZxZF TF can alleviate the inhibition of NADH dehydrogenase-like (NDH) cyclic electron flow of the poplar NDH pathway under drought stress, which plays an important role in reducing the excess pressure of electrons on the photosynthetic electron transport chain and maintaining the normal photosynthetic electron transport. In summary, the overexpression of ZxZF TFs can effectively alleviate the inhibition of drought on the assimilation of carbon in poplar and have a positive impact on light energy capture, the orderly transport of photosynthetic electron transport chain and the integrity of the photosystem, which is highly significant to acheivean in-depth understanding of the function of ZxZF TFs. This also provides an important basis for the breeding of new transgenic poplar varieties.

Overexpression of 2-Cys Peroxiredoxin alleviates the NaHCO3 stress-induced photoinhibition and reactive oxygen species damage of tobacco.

Plant 2-cysteine peroxiredoxin (2-Cys Prx) is a mercaptan peroxidase localized in chloroplasts and has unique catalytic properties. To explore the salt stress tolerance mechanisms of 2-Cys Prx in plants, we analyzed the effects of overexpressing the 2-CysPrx gene on the physiological and biochemical metabolic processes of tobacco under NaHCO3 stress through joint physiological and transcriptomic analysis. These parameters included growth phenotype, chlorophyll, photosynthesis, and antioxidant system. After NaHCO3 stress treatment, a total of 5360 differentially expressed genes (DEGs) were identified in 2-Cysprx overexpressed (OE) plants, and the number of DEGs was significantly lower than 14558 in wild-type (WT) plants. KEGG enrichment analysis showed that DEGs were mainly enriched in photosynthetic pathways, photosynthetic antenna proteins, and porphyrin and chlorophyll metabolism. Overexpressing 2-CysPrx significantly reduced the growth inhibition of tobacco induced by NaHCO3 stress, alleviating the down-regulation of the DEGs related to chlorophyll synthesis, photosynthetic electron transport and the Calvin cycle and the up-regulation of those related to chlorophyll degradation. In addition, it also interacted with other redox systems such as thioredoxins (Trxs) and the NADPH-dependent Trx reductase C (NTRC), and mediated the positive regulation of the activities of antioxidant enzymes such as peroxidase (POD) and catalase (CAT) and the expression of related genes, thereby reducing the accumulation of superoxide anion (O2·-), hydrogen peroxide (H2O2) and malondialdehyde (MDA). In conclusion, 2-CysPrx overexpression could alleviate the NaHCO3 stress-induced photoinhibition and oxidative damage by regulating chlorophyll metabolism, promoting photosynthesis and participating in the regulation of antioxidant enzymes, and thus improve the ability of plants to resist salt stress damage.

Microstructure Evolution and Performance Improvement of Silicon Carbide Ceramics via Impregnation Method.

The high topological silicon carbide (SiC) ceramics can be prepared by stereolithography (SLA) combined with liquid silicon infiltration (LSI) techniques. This paper aims to enhance the performance of SiC ceramics prepared by SLA and LSI techniques via the cyclic impregnation/carbonization of the precursor of carbon source solution before LSI. The effects of impregnation/carbonization cycles on the microstructure and properties of C/SiC preform and sintered body were analyzed in detail. The results show that, with the increase of impregnation/carbonization cycles, the porosity in the C/SiC preform decreases obviously and the content of secondary SiC in the sintered body increases effectively. Especially, when the impregnation/carbonization cycle was performed twice, the sintered body had the optimal mechanical properties. The value of flexural strength, bulk density and elastic modulus were 258.63 ± 8.33 MPa, 2.95 ± 0.02 g/cm3 and 425.16 ± 14.15 GPa, respectively. In addition, the thermal dimensional stability of sintered body was also improved by this method. This method proves that SiC ceramics prepared by SLA combined with LSI have the potential of applications in space optical mirrors.

Structure Evolution and Properties Modification for Reaction-Bonded Silicon Carbide.

Complex structure reaction-bonded silicon carbide (RB-SiC) can be prepared by reactive melt infiltration (RMI) and digital light processing (DLP). However, the strength and modulus of RB-SiC prepared by DLP are not sufficient, due to its low solid content (around 40 vol.%), compared with the traditional fabrication techniques (solid content > 60 vol.%). With this understanding, a new method to improve the properties of RB-SiC was proposed, by the impregnation of composite precursor into the porous preform. The composite precursor was composed of phenolic (PF) resin and furfuryl alcohol (FA). PF and FA were pyrolyzed at 1850 °C to obtain amorphous carbon and graphite into the porous preform, respectively. The effects of multiphase carbon on the microstructure and performance of RB-SiC was studied. When the mass ratio of PF to FA was 1/4, the solid content of RB-SiC increased from 40 vol.% to 68.6 vol.%. The strength, bulk density and modulus were 323.12 MPa, 2.94 g/cm3 and 348.83 Gpa, respectively. This method demonstrated that the reaction process between liquid Si and carbon could be controlled by the introduction of multiphase carbon into the porous preforms, which has the potential to regulate the microstructure and properties of RB-SiC prepared by additive manufacturing or other forming methods.

Challenges and strategies in high-accuracy manufacturing of the world's largest SiC aspheric mirror.

In the process of manufacturing the world's largest silicon carbide (SiC) aspheric mirror, the primary difficulties are mirror blank preparation, asphere fabrication, and testing, as well as cladding and coating. Specifically, the challenges include the homogeneity of the complicated structure casting, accuracy and efficiency of the fabrication process, print-through effect, fidelity and precision of test procedure, stress and denseness of cladding process, the dynamic range of interferometric measurement, and air turbulence error due to the long optical path. To break through such a barrier of difficulties, we proposed the water-soluble room temperature vanishing mold and gel casting technology, homogeneous microstructure reaction-formed joint technology, nano-accuracy efficient compound fabrication, gravity unloading technology, high-denseness low-defect physical vapor deposition (PVD) Si-cladding technology, test data fusion method, and time-domain averaging method, etc. Based on the proposed technologies and methods, we have accomplished the world's largest SiC aspheric mirror with a size of ⌀4.03 m. The impressive performance of the SiC aspheric mirror is validated by the characteristics of the fabricated SiC aspheric mirror. The aerial density of the SiC blank is less than 120 kg/m2, surface shape test accuracy is better than 6 nm RMS, thickness inhomogeneity of the cladding layer is less than 5%, and the final surface figure error and roughness are 15.2 nm RMS and 0.8 nm RMS, respectively.

Intracellular TMEM16A is necessary for myogenesis of skeletal muscle.

Transmembrane protein 16A (TMEM16A) localizes at plasma membrane and controls chloride influx in various type of cells. We here showed an intracellular localization pattern of TMEM16A molecules. In myoblasts, TMEM16A was primarily localized to the cytosolic compartment and partially co-localized with intracellular organelles. The global deletion of TMEM16A led to severe skeletal muscle developmental defect. In vitro observation showed that the proliferation of Tmem16a-/- myoblasts was significantly promoted along with activated ERK1/2 and Cyclin D expression; the myogenic differentiation was impaired accompanied by the enhanced caspase 12/3 activation, implying enhanced endoplasmic reticulum (ER) stress. Interestingly, the bradykinin-induced Ca2+ release from ER calcium store was significantly enhanced after TMEM16A deletion. This suggested a suppressing role of intracellular TMEM16A in ER calcium release whereby regulating the flux of chloride ion across the ER membrane. Our findings reveal a unique location pattern of TMEM16A in undifferentiated myoblasts and its role in myogenesis.