Mildly delignified softwood holocellulose fibers featuring native tracheid fiber cell wall structure and high hemicellulose content are prominent building blocks for wood derived fiber-based materials. However, preserving the natural alignment of long softwood fiber is challenging since top-down structure-retaining delignified softwood is unstable as extensive removal of lignin from intercellular space induces cracking and disintegration of wood structure. Here we report the use of chemical crosslinking pretreatment to improve the intercellular bonding between softwood fibers, therefore preserving the integrity of the naturally aligned softwood fibers after delignification. The crosslinked softwood veneer was delignified with peracetic acid and further densified into transparent and high-density film by thermal compression. The obtained transparent film of naturally aligned softwood holocellulose fibers showed high optical transmittance of 71 %, high haze of 85 %, strong optical anisotropy, as well as high tensile strength of 449 ± 58 MPa and high Young's modulus of 49.9 ± 5.6 GPa. This study provides a facile approach to preserve the natural alignment of softwood fibers for the fabrication of high performance holocellulose fibers-based materials.
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http://dx.doi.org/10.1016/j.carbpol.2024.122722 | DOI Listing |
Adv Sci (Weinh)
January 2025
DP Technology, Beijing, 100080, China.
Powder X-ray diffraction (PXRD) is a prevalent technique in materials characterization. While the analysis of PXRD often requires extensive human manual intervention, and most automated method only achieved at coarse-grained level. The more difficult and important task of fine-grained crystal structure prediction from PXRD remains unaddressed.
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January 2025
Department of Physics, University of Ottawa, Ottawa, ON, K1N 6N5, Canada.
We report a nonlinear terahertz (THz) detection device based on a metallic bull's-eye plasmonic antenna. The antenna, fabricated with femtosecond laser direct writing and deposited on a nonlinear gallium phosphide (GaP) crystal, focuses incoming THz waveforms within the sub-wavelength bull's eye region to locally enhance the THz field. Additionally, the plasmonic structure minimizes diffraction effects allowing a relatively long interaction length between the transmitted THz field and the co-propagating near-infrared gating pulse used in an electro-optic sampling configuration.
View Article and Find Full Text PDFNat Commun
January 2025
Institute of Innovative Materials, Department of Chemistry, College of Science, Southern University of Science and Technology, Shenzhen, China.
Natural materials with highly oriented heterogeneous structures are often lightweight but strong, stiff but tough and durable. Such an integration of diverse incompatible mechanical properties is highly desired for man-made materials, especially weak hydrogels which are lack of high-precision structural design. Herein, we demonstrate the fabrication of hierarchically aligned heterogeneous hydrogels consisting of a compactly crosslinked sheath and an aligned porous core with alignments of nanofibrils at multi-scales by a sequential self-assembly assisted salting out method.
View Article and Find Full Text PDFCurr Biol
December 2024
Université Paris Cité, CNRS, Institut Jacques Monod, 75013 Paris, France; Equipe Labellisée LIGUE Contre le Cancer, 75013 Paris, France. Electronic address:
The regulation of mitotic spindle positioning and orientation is central to the morphogenesis of developing embryos and tissues. In many multicellular contexts, cell geometry has been shown to have a major influence on spindle positioning, with spindles that commonly align along the longest cell shape axis. To date, however, we still lack an understanding of how the nature and amplitude of intracellular forces that position, orient, or hold mitotic spindles depend on cell geometry.
View Article and Find Full Text PDFStud Hist Philos Sci
January 2025
Colby College, 4550 Mayflower Hill, Lovejoy 247, Waterville, ME, 04901, USA. Electronic address:
In this paper, I defend a non-mechanistic interpretation of Kant's philosophy of nature. My interpretation contradicts the robust tradition of reading Kant as a mechanist about nature - or as someone who endorses the view that we can know the internally purposive causality characteristic of organisms has no place in nature. By attending closely to Kant's remarks about the possibility of internal purposiveness in nature and to key premises from Kant's arguments in the Antinomy of Teleological Judgment, we shall see that it is not only plausible, but preferable, to believe that internally purposive things (i.
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