This study reports the formation of biocompatible hydrogels using protein polymers from natural silk cocoon fibroins and sheep wool keratins. Silk fibroin protein contains β-sheet secondary structures, allowing for the formation of physical cross-linkers in the hydrogels. Comparative studies were performed on two groups of samples. In the first group, ultrasonication was used to induce a quick gelation of a protein aqueous solution, enhancing the ability of Bombyx mori silk fibroin chains to quickly entrap the wool keratin protein molecules homogenously. In the second group, silk/keratin mixtures were left at room temperature for days, resulting in naturally-assembled gelled solutions. It was found that silk/wool blended solutions can form hydrogels at different mixing ratios, with perfectly interconnected gel structure when the wool content was less than 30 weight percent (wt %) for the first group (ultrasonication), and 10 wt % for the second group (natural gel). Differential scanning calorimetry (DSC) and temperature modulated DSC (TMDSC) were used to confirm that the fibroin/keratin hydrogel system was well-blended without phase separation. Fourier transform infrared spectroscopy (FTIR) was used to investigate the secondary structures of blended protein gels. It was found that intermolecular β-sheet contents significantly increase as the system contains more silk for both groups of samples, resulting in stable crystalline cross-linkers in the blended hydrogel structures. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used to analyze the samples’ characteristic morphology on both micro- and nanoscales, which showed that ultrasonic waves can significantly enhance the cross-linker formation and avoid phase separation between silk and keratin molecules in the blended systems. With the ability to form cross-linkages non-chemically, these silk/wool hydrogels may be economically useful for various biomedical applications, thanks to the good biocompatibility of protein molecules and the various characteristics of hydrogel systems. 相似文献
The pine wood nematode, Bursaphelenchus xylophilus, causes huge economic losses in pine forests, has a complex life cycle, and shows the remarkable ability to survive under unfavorable and changing environmental conditions. This ability may be related to autophagy, which is still poorly understood in B. xylophilus and no autophagy-related genes have been previously characterized. In this study, transmission electron microscopy was used to confirm that autophagy exists in B. xylophilus. The full-length cDNAs of BxATG1 and BxATG8 were first cloned from B. xylophilus, and BxATG1 and BxATG8 were characterized using bioinformatics methods. The expression pattern of the autophagy marker BxATG8 was investigated using in situ hybridization (ISH). BxATG8 was expressed in esophageal gland and hypodermal seam cells. We tested the effects of RNA interference (RNAi) on BxATG1 and BxATG8. The results revealed that BxATG1 and BxATG8 were likely associated with propagation of nematodes on fungal mats. This study confirmed the molecular characterization and functions of BxATG1 and BxATG8 in B. xylophilus and provided fundamental information between autophagy and B. xylophilus. 相似文献
This paper is concerned with the application of energy efficient fluid power in mobile robots system and proposes a new fluid power converter system which is analogous to a boost converter in power electronics. The fluid power converter system is based on the principle of pulse-width modulation. The fluid power converter has an effect akin to an electrical switched inductance transformer, wherein the output pressure or flow rate can be stepped up or down. Using an inductive reactance device (an inertia mass-block), the output flow and pressure can be varied to meet the load by a means that does not rely on dissipation of power (the resistance control). The simulation model based on the mathematics models of the components is built to analyse the performance of the fluid power converter. It is clearly shown that the fluid power converter has higher energy efficiency than conventional resistance control manners.