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All-cellulosic materials called vulcanized fibers, in which cellulose fibers are gelatinized and adhered to each other by zinc chloride, have been known for more than 150 years. However, the swelling and adhesion mechanisms have not yet been clarified. In this study, X-ray diffraction, scanning electron microscopy (SEM) ，and specific surface area(SSA)analyses of cellulose sheets treated with different concentrations of aqueous zinc chloride solutions were performed to elucidate the behavior and mechanism of cellulose fibers adhering to one another during ZnCl 2 treatment. The X-ray diffraction analysis revealed that the ZnCl 2 treatment caused swelling of intercrystalline regions but did not significantly change the original crystal structure of cellulose I. The SEM observation of the freeze-dried sheets revealed less aggregated structures of the fine fibers and the existence of three-dimensionally entangled cellulose nanofibrils(CNFs)between the cellulose microfibers. The increased SSA values of the freeze-dried sheets supported the formation of CNFs during the ZnCl 2 treatment. These results indicate that in these all-cellulosic materials, CNFs are entangled and form dense networks that are not completely detached in water. In addition, the presence of moisture leads to more viscoelastic behavior as a result of slip between the CNFs during tensile testing.

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Background: Bipolar disorder (BD) is a serious psychiatric disorder that is associated with a high suicide rate, and for which no clinical biomarker has yet been identified. To address this issue, we investigated the use of magnetoencephalography (MEG) as a new prospective tool. MEG has been used to evaluate frequency-specific connectivity between brain regions; however, no previous study has investigated the frequencyspecific resting-state connectome in patients with BD. This resting-state MEG study explored the oscillatory representations of clinical symptoms of BD via graph analysis. Methods: In this prospective case-control study, 17 patients with BD and 22 healthy controls (HCs) underwent resting-state MEG and evaluations for depressive and manic symptoms. After estimating the source current distribution, orthogonalized envelope correlations between multiple brain regions were evaluated for each frequency band. We separated regions-of-interest into seven left and right network modules, including the frontoparietal network (FPN), limbic network (LM), salience network (SAL), and default mode network (DMN), to compare the intra-and inter-community edges between the two groups. Results: In the BD group, we found significantly increased inter-community edges of the right LM-right DMN at the gamma band, and decreased inter-community edges of the right SAL-right FPN at the delta band and the left SAL-right SAL at the theta band. Intracommunity edges in the left LM at the high beta band were significantly higher in the BD group than in the HC group. The number of connections in the left LM at the high beta band showed positive correlations with the subjective and objective depressive symptoms in the BD group. Conclusion: We introduced graph theory into resting-state MEG studies to investigate the functional connectivity in patients with BD. To the best of our knowledge, this is a novel approach that may be beneficial in the diagnosis of BD. This study describes the