Fabrication of high performance silk fibroin fibers via stable jet electrospinning for potential use in anisotropic tissue regeneration

The high performance of SF fibers is attributed to the high fiber alignment, molecular orientation and contents of the β-pleated sheet.

2D and 3D Supramolecular Structures of trans- and cis-Octahedral Coordination Compounds of Ethyl-5-methyl-4-imidazolecarboxylate with Transition Metal Ions

Ethyl-5-methyl-4-imidazolecarboxylate (emizco) is an important intermediate in the synthesis of pharmacological active compounds. In this work, there were synthetized and characterized the following coordination compounds with emizco: <em>trans</em>-[Co(emizco)₂(H₂O)₂](NO₃)₂ <strong>1</strong>, <em>trans</em>-[Ni(emizco)₂(H₂O)₂](NO₃)₂ <strong>2</strong>, <em>trans</em>-[Cd(emizco)₂(H₂O)₂](NO₃)₂ (<strong>3</strong>) and <em>cis</em>-[Cd(emizco)₂Br₂] (<strong>4</strong>). 2D or 3D supramolecular arrangements were stabilized. All nitrate <em>trans</em> octahedral compounds stabilized a 3D supramolecular arrangement <em>via</em> hydrogen bonding, throughout the nitrate anions, the ligand and the coordinated water molecules; the <em>cis</em>-octahedral halide complex formed a 2D pleated sheet arrangement, by intermolecular π stacking and halide-hydrogen bonding.

rac-5-Bromo-N-benzylisatincreatinine ethanol monosolvate

In the title compound [systematic name:rac-1-benzyl-5-bromo-3-hydroxy-3-(2-imino-3-methyl-5-oxoimidazolidin-4-yl)-2,3-dihydro-1H-indol-2-one ethanol monosolvate], C19H17BrN4O3·C2H5OH, which crystallized as a racemate (RRandSS), the isatin ring is almost planar, with an r.m.s. deviations from the mean plane of 0.0276 (14) Å. The phenyl ring of the benzyl group makes a dihedral angle with the mean plane of the isatin ring of 87.40 (5)° and the dihedral angle between the imidazole and isatin rings is 58.56 (7)°. In the crystal, molecules are linked into two-dimensional pleated-sheet networks in theacplane formed by O—H...O, N—H...O and O—H...N hydrogen bonds; within these sheets there areR44(10) rings that involve three molecules of the title compound and a single ethanol solvent molecule. In addition, there are π–π interactions between inversion-related benzyl groups, with an interplanar spacing of 3.444 (3) Å.

Characterization of Secondary Structure Transformation of Stretched and Slenderized Wool Fibers with FTIR Spectra

Characterizations of wool fibers were performed with FTIR testing technology for two categories of stretched wool fibers, i.e., the OPTIMTM-Fine wool, and the stretched wool processed on TJGD-ERDOS 02 stretching equipment, developed at College of Textile Engineering, Tianjin Polytechnic University, Tianjin, China. It was observed that the two types of stretched wool fibers could be characterized by the IR transmittance peaks at 1620 ∼ 1630 cm-1 and 1510 ∼ 1520 cm-1. It was evidenced that upon stretching the secondary structure of the wool fibers transformed from alpha helix, the typical secondary structure of raw wool, to beta pleated sheet, the typical secondary structure of native silk, which was supported by the change in cross-sectional morphology and stress-strain curve.