Sequences of intrafusal fiber formation are muscle-dependent in rat hindlimbs

High-speed melt spinning of thermotropic liquid crystalline polymer (TLCP) resin composed of 4-hydroxybenzoic acid (HBA) and 2-hydroxy-6-napthoic acid (HNA) monomers in a molar ratio of 73/27 was conducted to investigate the characteristic structure development of the fibers under industrial spinning conditions, and the obtained as-spun TLCP fibers were analyzed in detail. The tensile strength and modulus of the fibers increased with shear rate in nozzle hole, draft in spin-line and spinning temperature and exhibited the high values of approximately 1.1 and 63 GPa, respectively, comparable to those of industrial as-spun TLCP fibers, at a shear rate of 70,000 s−1 and a draft of 25. X-ray diffraction demonstrated that the mechanical properties of the fibers increased with the crystalline orientation factor (fc) and the fractions of highly oriented crystalline and non-crystalline anisotropic phases. The results of structure analysis indicated that a characteristic skin–core structure developed at high drafts (i.e., spinning velocity) and low spinning temperatures, which contributed to weakening the mechanical properties of the TLCP fibers. It is supposed that this heterogeneous structure in the cross-section of the fibers was induced by differences in the cooling rates of the skin and core of the fiber in the spin-line.

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EpCAM promotes endosomal modulation of the cortical RhoA zone for epithelial organization

Nature Communications ◽

10.1038/s41467-021-22482-9 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Cécile Gaston ◽

Simon De Beco ◽

Bryant Doss ◽

Meng Pan ◽

Estelle Gauquelin ◽

...

Keyword(s):

Cell Shape ◽

Specific Protein ◽

Cell Polarization ◽

Stress Fiber ◽

Fiber Formation ◽

Endosomal Trafficking ◽

Transient Zone ◽

And Behavior ◽

Fine Tune

AbstractAt the basis of cell shape and behavior, the organization of actomyosin and its ability to generate forces are widely studied. However, the precise regulation of this contractile network in space and time is unclear. Here, we study the role of the epithelial-specific protein EpCAM, a contractility modulator, in cell shape and motility. We show that EpCAM is required for stress fiber generation and front-rear polarity acquisition at the single cell level. In fact, EpCAM participates in the remodeling of a transient zone of active RhoA at the cortex of spreading epithelial cells. EpCAM and RhoA route together through the Rab35/EHD1 fast recycling pathway. This endosomal pathway spatially organizes GTP-RhoA to fine tune the activity of actomyosin resulting in polarized cell shape and development of intracellular stiffness and traction forces. Impairment of GTP-RhoA endosomal trafficking either by silencing EpCAM or by expressing Rab35/EHD1 mutants prevents proper myosin-II activity, stress fiber formation and ultimately cell polarization. Collectively, this work shows that the coupling between co-trafficking of EpCAM and RhoA, and actomyosin rearrangement is pivotal for cell spreading, and advances our understanding of how biochemical and mechanical properties promote cell plasticity.

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Functional Bionanocomposite Fibers of Chitosan Filled with Cellulose Nanofibers Obtained by Gel Spinning

Polymers ◽

10.3390/polym13101563 ◽

2021 ◽

Vol 13 (10) ◽

pp. 1563

Author(s):

Sofia Marquez-Bravo ◽

Ingo Doench ◽

Pamela Molina ◽

Flor Estefany Bentley ◽

Arnaud Kamdem Tamo ◽

...

Keyword(s):

Mechanical Properties ◽

Mechanical Performance ◽

Cellulose Nanofibers ◽

Microstructural Characterization ◽

Fiber Formation ◽

Fiber Direction ◽

Composite Fibers ◽

X Ray Diffraction ◽

Gel Spinning ◽

X Ray

Extremely high mechanical performance spun bionanocomposite fibers of chitosan (CHI), and cellulose nanofibers (CNFs) were successfully achieved by gel spinning of CHI aqueous viscous formulations filled with CNFs. The microstructural characterization of the fibers by X-ray diffraction revealed the crystallization of the CHI polymer chains into anhydrous chitosan allomorph. The spinning process combining acidic–basic–neutralization–stretching–drying steps allowed obtaining CHI/CNF composite fibers of high crystallinity, with enhanced effect at incorporating the CNFs. Chitosan crystallization seems to be promoted by the presence of cellulose nanofibers, serving as nucleation sites for the growing of CHI crystals. Moreover, the preferential orientation of both CNFs and CHI crystals along the spun fiber direction was revealed in the two-dimensional X-ray diffraction patterns. By increasing the CNF amount up to the optimum concentration of 0.4 wt % in the viscous CHI/CNF collodion, Young’s modulus of the spun fibers significantly increased up to 8 GPa. Similarly, the stress at break and the yield stress drastically increased from 115 to 163 MPa, and from 67 to 119 MPa, respectively, by adding only 0.4 wt % of CNFs into a collodion solution containing 4 wt % of chitosan. The toughness of the CHI-based fibers thereby increased from 5 to 9 MJ.m−3. For higher CNFs contents like 0.5 wt %, the high mechanical performance of the CHI/CNF composite fibers was still observed, but with a slight worsening of the mechanical parameters, which may be related to a minor disruption of the CHI matrix hydrogel network constituting the collodion and gel fiber, as precursor state for the dry fiber formation. Finally, the rheological behavior observed for the different CHI/CNF viscous collodions and the obtained structural, thermal and mechanical properties results revealed an optimum matrix/filler compatibility and interface when adding 0.4 wt % of nanofibrillated cellulose (CNF) into 4 wt % CHI formulations, yielding functional bionanocomposite fibers of outstanding mechanical properties.

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Pyridazine-3,6-diol-annulated Tetrathiafulvalene: Self-assembly and Fiber Formation Triggered by Diamine Addition

Chemistry Letters ◽

10.1246/cl.141165 ◽

2015 ◽

Vol 44 (4) ◽

pp. 448-450 ◽

Cited By ~ 5

Author(s):

Ryota Inoue ◽

Masashi Hasegawa ◽

Yasuhiro Mazaki

Keyword(s):

Self Assembly ◽

Fiber Formation

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Emerging Silk Material Trends: Repurposing, Phase Separation and Solution-Based Designs

Materials ◽

10.3390/ma14051160 ◽

2021 ◽

Vol 14 (5) ◽

pp. 1160

Author(s):

F. Philipp Seib

Keyword(s):

Phase Separation ◽

Recent Progress ◽

Fiber Formation ◽

Live Cells ◽

Specific Reference ◽

New Developments ◽

Silk Fabrics ◽

Induced Crystallization ◽

Liquid Liquid Phase Separation

Silk continues to amaze. This review unravels the most recent progress in silk science, spanning from fundamental insights to medical silks. Key advances in silk flow are examined, with specific reference to the role of metal ions in switching silk from a storage to a spinning state. Orthogonal thermoplastic silk molding is described, as is the transfer of silk flow principles for the triggering of flow-induced crystallization in other non-silk polymers. Other exciting new developments include silk-inspired liquid–liquid phase separation for non-canonical fiber formation and the creation of “silk organelles” in live cells. This review closes by examining the role of silk fabrics in fashioning facemasks in response to the SARS-CoV-2 pandemic.

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Coacervation of Tropoelastin Results in Fiber Formation

Journal of Biological Chemistry ◽

10.1016/s0021-9258(19)43030-5 ◽

1974 ◽

Vol 249 (3) ◽

pp. 997-998 ◽

Cited By ~ 2

Author(s):

Betty A. Cox ◽

Barry C. Starcher ◽

Dan W. Urry

Keyword(s):

Fiber Formation

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Fiber Formation of printED CF / PEEK with different Nozzle shapes

Polymer International ◽

10.1002/pi.6196 ◽

2021 ◽

Author(s):

Alexander Matschinski ◽

Philipp Ziegler ◽

Tobias Abstreiter ◽

Tobias Wolf ◽

Klaus Drechsler

Keyword(s):

Fiber Formation

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Clinical Relevance of Elastin in the Structure and Function of Skin

Aesthetic Surgery Journal Open Forum ◽

10.1093/asjof/ojab019 ◽

2021 ◽

Author(s):

Leslie Baumann ◽

Eric F Bernstein ◽

Anthony S Weiss ◽

Damien Bates ◽

Shannon Humphrey ◽

...

Keyword(s):

Wound Healing ◽

Clinical Relevance ◽

Structural Integrity ◽

Elastic Fiber ◽

Subcutaneous Fat ◽

Structure And Function ◽

Fiber Formation ◽

Elastic Fibers ◽

Superficial Dermis ◽

And Function

Abstract Elastin is the main component of elastic fibers, which provide stretch, recoil, and elasticity to the skin. Normal levels of elastic fiber production, organization, and integration with other cutaneous extracellular matrix proteins, proteoglycans, and glycosaminoglycans are integral to maintaining healthy skin structure, function, and youthful appearance. Although elastin has very low turnover, its production decreases after individuals reach maturity and it is susceptible to damage from many factors. With advancing age and exposure to environmental insults, elastic fibers degrade. This degradation contributes to the loss of the skin’s structural integrity; combined with subcutaneous fat loss, this results in looser, sagging skin, causing undesirable changes in appearance. The most dramatic changes occur in chronically sun-exposed skin, which displays sharply altered amounts and arrangements of cutaneous elastic fibers, decreased fine elastic fibers in the superficial dermis connecting to the epidermis, and replacement of the normal collagen-rich superficial dermis with abnormal clumps of solar elastosis material. Disruption of elastic fiber networks also leads to undesirable characteristics in wound healing, and the worsening structure and appearance of scars and stretch marks. Identifying ways to replenish elastin and elastic fibers should improve the skin’s appearance, texture, resiliency, and wound-healing capabilities. However, few therapies are capable of repairing elastic fibers or substantially reorganizing the elastin/microfibril network. This review describes the clinical relevance of elastin in the context of the structure and function of healthy and aging skin, wound healing, and scars and introduces new approaches being developed to target elastin production and elastic fiber formation.

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