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Cellulose nanofibril (CNF) aerogels have attracted great interests in recent years due to the low cost, sustainability and biocompatibility of raw CNF. However, the poor thermal stability and flammable feature of CNF aerogels have limited their wider applications. In this paper, polydopamine/CNF composite aerogels with good comprehensive properties are fabricated by modification of CNF with polydopamine and metal coordination bonds crosslinking. The microstructure and properties of composite aerogels are thoroughly characterized by a variety of tests. It is found that the microstructure of aerogels are more regular and the compressive strength of aerogels are enhanced by the incorporation of polydopamine and Fe3+ crosslinking. Importantly, the thermal stability and flame resistance of aerogels are significantly improved, which permit the application of composite aerogels in high-temperature thermal insulation. In addition, the reversible characteristic of metal coordination bonds allows the water induced healing of fractured composite aerogels. This study is expected to provide information for future development of green and high-performance aerogels.

Herein, carboxyl-rich cellulose nanocrystals (CNC) were obtained through a designed TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl) mediated oxidation process without any subsequent mechanical treatment, which was proved to be widely suitable for commonly used cellulosic sources, including fibril-like fibers and lignocellulose biomasses. CNC prepared from the acid-free process showed better dispersion stability, less aggregation, higher aqueous UV transmittance and crystallinity compared with that from sulfuric acid hydrolysis process. Furthermore, the residuals in the insoluble precipitate were further conducted ultrasonic treatment and extra CNC was obtained from the oxidized cotton and ramie cellulose while cellulose nanofibril (CNF) was extracted from rice straw and pine powder, attributing to their different native structures. The total yields of nanocelluloses (NCs) were up to 63.2–68.3 %, improving the utilization ratio of the raw materials. This work provided a widely applicable acid- and mechanic-free route in fabricating CNC with inherent carboxyl groups and described an understanding of the relationship between the native structure of raw materials and their products, which is beneficial for improving the application of NCs.

Although p21 activated kinase 5 (PAK5) is related to the progression of multiple cancers, its biological function in breast cancer remains unclear. Apoptosis-inducing factor (AIF) is a vital apoptosis factor in mitochondria, which can be released from mitochondria and enter the nucleus, causing caspase-independent apoptosis. In this study, we reveal that PAK5 inhibits apoptosis by preventing the nuclear translocation of AIF. PAK5 inhibits the release of AIF from mitochondria in breast cancer cells by decreasing the mitochondria membrane permeability and increasing the membrane potential. Furthermore, PAK5 phosphorylates AIF at Thr281 site to inhibit the formation of AIF/importin α3 complex, leading to decrease AIF nuclear translocation. Functionally, we demonstrate that PAK5-mediated AIF phosphorylation promotes the proliferation of breast cancer cells and accelerates the growth of breast cancer in vivo. Significantly, PAK5 and AIF expression in breast cancer are positively correlated with poor patient prognosis. PAK5 expression is negatively correlated with AIF nuclear translocation. These results suggest that PAK5-AIF signaling pathway may play an essential role in mammary tumorigenesis, providing a new therapeutic target for the treatment of breast cancer.

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Multifunctional materials for water purification have attracted great attention due to the increased water pollution problems. However, fabricating the low-cost and recyclable separation material is still a challenge. Herein, we developed an Ag/TiO2@PDMS coated cotton fabric with self-clean ability, high flux, superior visible-light photocatalysts ability, and recyclability via the “powder + glue” strategy. The composites exhibit superhydrophobic (water contact angle 157°), and high separation efficiency. The separation efficiency of 20 times of repeated use remains 16322 Lm−2h−1 and the degradation rate of methylene blue (MB) remains almost no change. The high oil purification, catalytic property, excellent stability in harsh condition and recyclability enables the material as a satisfactory candidate for water purification.

Cellulose nanofibril (CNF) aerogels have attracted great interests in recent years due to the low cost, sustainability and biocompatibility of raw CNFs. However, the poor thermal stability and flammable feature of CNF aerogels have limited their wider applications. In this paper, polydopamine/CNF composite aerogels with good comprehensive properties are fabricated by modification of CNF with polydopamine and metal coordination bonds crosslinking. The microstructure and properties of composite aerogels are thoroughly characterized by a variety of tests. It is found that the microstructure of aerogels are more regular and the compressive strength of aerogels are enhanced by the incorporation of polydopamine and Fe3+ crosslinking. Importantly, the thermal stability and flame resistance of aerogels are significantly improved, which permit the application of composite aerogels in high-temperature thermal insulation. In addition, the reversible characteristic of metal coordination bonds allows the water induced healing of fractured composite aerogels. This study is expected to provide information for future development of green and high-performance aerogels.

P21-activated kinase 5 (PAK5) plays an important role in tumors. However, the functional role of PAK5 in mammary tumorigenesis in vivo remains unclear. Here, we show that PAK5 deficiency represses MMTV-PyVT-driven breast tumorigenesis. DEAD-box RNA helicase 5 (DDX5) is a substrate of PAK5, which is phosphorylated on threonine 69. PAK5-mediated DDX5 phosphorylation promotes breast cancer cell proliferation and metastasis. The increased expression levels of PAK5 and phospho-DDX5 threonine 69 are associated with metastasis and poor clinical outcomes of patients. PAK5 facilitates the phosphorylation-dependent sumoylation of DDX5 to stabilize DDX5. Both the phosphorylation and sumoylation of DDX5 enhance the formation of a DDX5/Drosha/DGCR8 complex, thus promoting microRNA-10b processing. Finally, we verify decreased expression of DDX5 phosphorylation and sumoylation and mature miR-10b in PAK5

The development of efficient electromagnetic interference (EMI) shielding materials with high electromagnetic waves (EMWs) absorption capacity is of great significance to alleviate secondary EMWs pollution. Herein, multilayered composites were prepared by stacking cellulose nanofibril (CNF)/reduced graphene oxide (rGO) aerogels and rGO film together. The porous aerogels and the dense film serve as the EMWs absorbing layer and reflecting layer, respectively. When the EMWs enter the multilayer composites, they go through the process of absorption-reflection-reabsorption, resulting in a high EMI shielding effectiveness (SE) of ~32 dB. Furthermore, both experimental and theoretical analyses were adopted to explore the effect of arrangement order of CNF/rGO aerogels on EMI shielding performance. The results indicate that composites with progressively higher graphene content exhibit a higher EMWs absorption capacity at the same total EMI SE. This work offers a feasible design for improving EMWs absorption without affecting the overall EMI shielding performance of the material.

Precise measurement of Polyester Filament Yarn (PFY) tension in the spinning process is critical to ensure good uniformity of product quality. A newly proposed real-time method is used to estimate the tension based on the natural frequencies extraction of the PFY. The theoretical relationship is established among the PFY tension, the spinning speed, and the first natural frequency based on the characteristics of the transverse dynamic vibration of the PFY in the spinning process. Then, an improved wavelet threshold denoising model has been applied to denoising the vibration signals, and the gravity center frequency of the denoised amplitude spectrum is used to extract the natural frequency of the PFY, and then the PFY tension can be estimated efficiently by employing the extracted natural frequencies. To monitor the uniformity of product quality, a new real-time evaluation index, namely the PFY tension fluctuation rate, is proposed to evaluate the overall fluctuation of PFY tension, which can be used for quantitative analysis and comparison of PFY tension. Additionally, the measurement data is of great significance to the evaluation and optimization of the performance of high-speed spinning equipment. The research intends to serve as a basis for the design of the spinning technology as well as its reliable operation.

Ionic liquid-based lignocellulose aerogel systems have attracted significant focus in advanced material research due to their intrinsic environment-friendly properties. Use of co-solvent is deemed useful in improving these systems efficiency without affecting reaction dynamics. Herein, a green synthesis strategy is reported to produce highly porous, physically cross-linked lignocellulose aerogel by dissolving lignocellulose biomass obtained from the cotton stalk in 1-allyl-3-methylimidazolium chloride/dimethyl sulfoxide (AmimCl/DMSO) co-solvent system. Samples with different concentrations were treated under both cyclic conventional freezing-thawing conditions (−20 °C to 20 °C) and liquid nitrogen freezing-thawing conditions (−196 °C to 20 °C) followed by solvent exchange and freeze drying. Scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) analysis of these lignocellulose samples showed that conventional freezing-thawing treated samples exhibit hierarchical 3D open porous “web-like” structure with a low specific surface area and larger dominant pore diameter. On the other hand, use of liquid nitrogen freezing-thawing treatment resulted in the creation of “film-like” porous structure with a higher specific surface area and relatively smaller dominant pore diameter. Quantitative analysis through Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and thermo-gravimetric analysis (TGA) verified that cyclic freezing-thawing treatment has potential to fix all major components of lignocellulose in a matrix. The proposed strategy is not only environmentally benign but also the cost-effective making an ionic liquid-based system more commercially viable.

Attributed to low cost, renewable, and high availability, cellulose-based aerogels are desirable materials for various applications. However, mechanical robustness and functionalization remain huge challenges. Herein, we synthesized a recoverable, anisotropic cellulose nanofiber (CNF) / chitosan (CS) aerogel via directional freeze casting and chemical cross-link process. The chitosan was performed as strength polymers to prohibits the shrinkage and retains the structural stability of 3D cellulose nanofiber skeleton, endowing the composite aerogel with satisfactory deformation recovery ability (without loss under 60 % stress cycled 100 times). The CNF/CS composite aerogel has ultralow density (∼8.4 mg/cm3), high temperature-invariant (above 300 °C) and high porosity (98 %). The CNF/CS aerogel demonstrates anisotropic thermal insulation properties with low thermal conductivity (28 mWm−1 K−1 in rational direction and 36 mW m−1 K−1 in the axial direction). Moreover, the composite aerogel (water contact angle ∼148°) exhibited outstanding oil/water selectivity and high absorption capacity (82–253 g/g) for various oils and organic solvents. Therefore, the multifunctional CNF/CS composite aerogels are potential materials for thermal management and oil absorption applications.

The aim of this work is to improve the economic value of corn husk, and to make better use of corn husk nanocellulose (NC). Corn husk NC was extracted via acid hydrolysis, TEMPO oxidation and high intensity ultrasonication methods, which was named AH-NC, TO-NC and US-NC, respectively. The NC was carefully characterized by transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis and particle size and zeta potential analyzer. The results showed the preparation methods didn’t change the main chemical structure of cellulose. The crystallographic form of the three kinds of NC still was cellulose I. However, the effects of preparation methods on the morphology and properties were obvious. Among the three kinds of NC, TO-NC had the largest aspect ratio, and the best dispersion stability in diameter, but very low thermal stability. The AH-NC exhibited the highest crystallinity and best thermal stability, but a small aspect ratio. US-NC possessed low crystallinity and poor dispersion stability.

Cellulose nanocrystal (CNC) was extracted from Carex meyeriana Kunth (CMK) by a combination of TEMPO oxidation and mechanical homogenization method, and used to remove methylene blue (MB) from aqueous solution. After alkali-oxygen treatment, the aqueous biphasic system (polyethylene glycol/inorganic salt) was applied to further remove lignin from CMK. The characteriazation of CNC, and the effects of H2O2 dosage, CNC dosage, adsorption time, and initial MB concentration on the MB removal capacity of CNC were investigated. The results showed that the removal percentage of MB by CNC was raised with the increase of H2O2 and CNC dosage. The adsorption kinetics of prepared CNC followed the pseudo-second-order model, and the adsorption isotherms fitted well to the Langmuir model with a calculated maximum adsoption capacity of 217.4mg/g, which was higher than those of CNC extracted by acid hydrolysis method, indicating CNC extracted from CMK had promising potentials in the field of MB adsorption.

This thesis summarizes the author's research into the uniaxial stretch process of ultra-strength steel, which was made by means of sound emission and fracture surface observation. In the article, the author suggests a new idea for the sectionalized power hardening and the division of the specimen fracture surface. To confirm this new idea, a theoretical explanation is given. Also included is a physical graph of the deformation and fracture during the uniaxial stretch.