Different Conformations of Surface Cellulose Molecules in Native Cellulose Microfibrils Revealed by Layer-by-Layer Peeling

Layer-by-layer peeling of surface molecules of native cellulose microfibrils was performed using a repeated sequential process of 2,2,6,6-tetramethylpiperidine-1-oxyl radical-mediated oxidation followed by hot alkali extraction. Both highly crystalline algal and tunicate celluloses and low-crystalline cotton and wood celluloses were investigated. Initially, the C6-hydroxy groups of the outermost surface molecules of each algal cellulose microfibril facing the exterior had the gauche–gauche (<i>gg</i>) conformation, whereas those facing the interior had the gauche–trans (<i>gt</i>) conformation. All the other C6-hydroxy groups of the cellulose molecules inside the microfibrils contributing to crystalline cellulose I had the trans–gauche (<i>tg</i>) conformation. After surface peeling, the originally second-layer molecules from the microfibril surface became the outermost surface molecules, and the original <i>tg</i> conformation changed to <i>gg</i> and <i>gt</i> conformations. The plant cellulose microfibrils likely had disordered structures for both the outermost surface and second-layer molecules, as demonstrated using the same layer-by-layer peeling technique

Supplementary_material_789453 – Supplemental material for Intra-individual biomechanical effects of a non-microprocessor-controlled stance-yielding prosthetic knee during ramp descent in persons with unilateral transfemoral amputation

<p>Supplemental material, Supplementary_material_789453 for Intra-individual biomechanical effects of a non-microprocessor-controlled stance-yielding prosthetic knee during ramp descent in persons with unilateral transfemoral amputation by Yusuke Okita, Nobuya Yamasaki, Takashi Nakamura, Tomoki Mita, Tsutomu Kubo, Atsuko Mitsumoto and Toru Akune in Prosthetics and Orthotics International</p