scholarly journals Silk Fibroin: An Ancient Material for Repairing the Injured Nervous System

Pharmaceutics ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 429
Author(s):  
Mahdi Yonesi ◽  
Mario Garcia-Nieto ◽  
Gustavo V. Guinea ◽  
Fivos Panetsos ◽  
José Pérez-Rigueiro ◽  
...  
Keyword(s):  
Nervous System ◽  
Textile Industry ◽  
Mechanical Performance ◽  
Antioxidant Properties ◽  
Natural Fibers ◽  
Clinical Settings ◽  
Stem And Progenitor Cells ◽  
Peripheral Trauma ◽  
Main Component ◽  
Silkworm Silk

Silk refers to a family of natural fibers spun by several species of invertebrates such as spiders and silkworms. In particular, silkworm silk, the silk spun by Bombyx mori larvae, has been primarily used in the textile industry and in clinical settings as a main component of sutures for tissue repairing and wound ligation. The biocompatibility, remarkable mechanical performance, controllable degradation, and the possibility of producing silk-based materials in several formats, have laid the basic principles that have triggered and extended the use of this material in regenerative medicine. The field of neural soft tissue engineering is not an exception, as it has taken advantage of the properties of silk to promote neuronal growth and nerve guidance. In addition, silk has notable intrinsic properties and the by-products derived from its degradation show anti-inflammatory and antioxidant properties. Finally, this material can be employed for the controlled release of factors and drugs, as well as for the encapsulation and implantation of exogenous stem and progenitor cells with therapeutic capacity. In this article, we review the state of the art on manufacturing methodologies and properties of fiber-based and non-fiber-based formats, as well as the application of silk-based biomaterials to neuroprotect and regenerate the damaged nervous system. We review previous studies that strategically have used silk to enhance therapeutics dealing with highly prevalent central and peripheral disorders such as stroke, Alzheimer’s disease, Parkinson’s disease, and peripheral trauma. Finally, we discuss previous research focused on the modification of this biomaterial, through biofunctionalization techniques and/or the creation of novel composite formulations, that aim to transform silk, beyond its natural performance, into more efficient silk-based-polymers towards the clinical arena of neuroprotection and regeneration in nervous system diseases.

scholarly journals Development and Characterization of Weft-Knitted Fabrics of Naturally Occurring Polymer Fibers for Sustainable and Functional Textiles

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 665
Author(s):  
Marcela Ferrándiz ◽  
Eduardo Fages ◽  
Sandra Rojas-Lema ◽  
Juan Ivorra-Martinez ◽  
Jaume Gomez-Caturla ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Textile Industry ◽  
Mechanical Performance ◽  
Natural Fibers ◽  
Antimicrobial Properties ◽  
Fiber Formation ◽  
Knitted Fabrics ◽  
Functional Textiles ◽  
Naturally Occurring ◽  
Bacteria And Fungi

This study focuses on the potential uses in textiles of fibers of soy protein (SP) and chitin, which are naturally occurring polymers that can be obtained from agricultural and food processing by-products and wastes. The as-received natural fibers were first subjected to a three-step manufacturing process to develop yarns that were, thereafter, converted into fabrics by weft knitting. Different characterizations in terms of physical properties and comfort parameters were carried out on the natural fibers and compared to waste derived fibers of coir and also conventional cotton and cotton-based fibers, which are widely used in the textile industry. The evaluation of the geometry and mechanical properties revealed that both SP and chitin fibers showed similar fineness and tenacity values than cotton, whereas coir did not achieve the expected properties to develop fabrics. In relation to the moisture content, it was found that the SP fibers outperformed the other natural fibers, which could successfully avoid variations in the mechanical performance of their fabrics as well as impair the growth of microorganisms. In addition, the antimicrobial activity of the natural fibers was assessed against different bacteria and fungi that are typically found on the skin. The obtained results indicated that the fibers of chitin and also SP, being the latter functionalized with biocides during the fiber-formation process, showed a high antimicrobial activity. In particular, reductions of up to 100% and 60% were attained for the bacteria and fungi strains, respectively. Finally, textile comfort was evaluated on the weft-knitted fabrics of the chitin and SP fibers by means of thermal and tactile tests. The comfort analysis indicated that the thermal resistance of both fabrics was similar to that of cotton, whereas their air permeability was higher, particularly for chitin due to its higher fineness, which makes these natural fibers very promising for summer clothes. Both the SP and chitin fabrics also presented relatively similar values of fullness and softness than the pure cotton fabric in terms of body feeling and richness. However, the cotton/polyester fabric was the only one that achieved a good range for uses in winter-autumn cloths. Therefore, the results of this work demonstrate that non-conventional chitin and SP fibers can be considered as potential candidates to replace cotton fibers in fabrics for the textile industry due to their high comfort and improved sustainability. Furthermore, these natural fibers can also serve to develop novel functional textiles with antimicrobial properties.

scholarly journals Mechanical Properties of Boehmeria nivea Natural Fabric Reinforced Epoxy Matrix Composite Prepared by Vacuum-Assisted Resin Infusion Molding

Polymers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1311 ◽  
Author(s):  
Fabio da Costa Garcia Filho ◽  
Fernanda Santos da Luz ◽  
Lucio Fabio Cassiano Nascimento ◽  
Kestur Gundappa Satyanarayana ◽  
Jaroslaw Wieslaw Drelich ◽  
...  
Keyword(s):  
Mechanical Performance ◽  
Volume Fraction ◽  
Natural Fibers ◽  
Ramie Fiber ◽  
Resin Infusion ◽  
Lignocellulosic Fibers ◽  
Boehmeria Nivea ◽  
Fabric Composites ◽  
Epoxy Matrix Composite ◽  
Efficient Alternative

Natural lignocellulosic fibers and corresponding fabrics have been gaining notoriety in recent decades as reinforcement options for polymer matrices associated with industrially applied composites. These natural fibers and fabrics exhibit competitive properties when compared with some synthetics such as glass fiber. In particular, the use of fabrics made from natural fibers might be considered a more efficient alternative, since they provide multidirectional reinforcement and allow the introduction of a larger volume fraction of fibers in the composite. In this context, it is important to understand the mechanical performance of natural fabric composites as a basic condition to ensure efficient engineering applications. Therefore, it is also important to recognize that ramie fiber exhibiting superior strength can be woven into fabric, but is the least investigated as reinforcement in strong, tough polymers to obtain tougher polymeric composites. Accordingly, this paper presents the preparation of epoxy composite containing 30 vol.% Boehmeria nivea fabric by vacuum-assisted resin infusion molding technique and mechanical behavior characterization of the prepared composite. Obtained results are explained based on the fractography studies of tested samples.

A new strategy to improve ramie degumming based on removal of the xylan branched structure

2021 ◽  
pp. 004051752110449
Author(s):  
Huihui Wang ◽  
Tong Shu ◽  
Pandeng Li ◽  
Yun Bai ◽  
Mengxiong Xiang ◽  
...  
Keyword(s):  
Removal Rate ◽  
Natural Fibers ◽  
Green Manufacturing ◽  
Operating Conditions ◽  
Ramie Fiber ◽  
Wild Type ◽  
Acetyl Xylan Esterase ◽  
Degumming Process ◽  
Main Component ◽  
Engineered Strain

Ramie fiber is known as the “king of natural fibers,” and the key to its wide application is efficient and green manufacturing. Microbial degumming has gradually become a hot area of research due to its environmental protection and mild operating conditions. However, some gummy materials remain after microbial degumming. Xylan is the main component of residual gums; its acetylated branched chains create the space barrier that makes the removal of hemicellulose difficult during ramie degumming. An acetyl xylan esterase (AXE) was obtained from Bacillus pumilus and characterized to solve this problem. Its optimum temperature and pH were 35°C and 8.0, respectively, and it had good temperature and pH stability. These properties were consistent with the conditions of ramie degumming and they laid a foundation for the application of AXE in ramie degumming. Besides, an engineered strain with a high activity of AXE was constructed successfully on the basis of the wild-type degumming strain Pectobacterium carotovorum HG-49 and used for ramie degumming. The removal rate of hemicellulose and total gums by the engineered strain increased by 4.89% and 2.53%, respectively, compared with that of the wild-type strain. Moreover, the role of this AXE in ramie degumming was further proven by X-ray diffraction and scanning electron microscopy. This study showed that AXE played an important role in the removal of hemicellulose in the degumming process of ramie fibers, thus providing a promising degumming strategy for ramie and other bast fiber plants.

Development of Banana/Coir Natural Fibers Reinforced Polypropylene Hybrid Composites: The Effect of MA-g-PP (Maleic Anhydride Grafted Polypropylene) on Mechanical Properties and Thermal Properties

2021 ◽  
Vol 32 ◽  
pp. 85-97
Author(s):  
Gunturu Bujjibabu ◽  
Vemulapalli Chittaranjan Das ◽  
Malkapuram Ramakrishna ◽  
Konduru Nagarjuna
Keyword(s):  
Mechanical Properties ◽  
Impact Strength ◽  
Coupling Agent ◽  
Mechanical Performance ◽  
Hybrid Composites ◽  
Natural Fibers ◽  
Mechanical Tests ◽  
Coir Fiber ◽  
Banana Fiber ◽  
C Fibers

Banana/Coir fiber reinforced polypropylene hybrid composites was formulated by using twin screw extruder and injection molding machine. Specimens were prepared untreated and treated B/C Hybrid composites with 4% and 8% of MA-g-PP to increase its compatibility with the polypropylene matrix. Both the without MA-g-PP and with MA-g-PP B/C hybrid composites was utilized and three levels of B/C fiber loadings 15/5, 10/10 and 5/15 % were used during manufacturing of B/C reinforced polypropylene hybrid composites. In this work mechanical performance (tensile, flexural and impact strengths) of untreated and treated (coupling agent) with 4% and 8% of MA-g-PP B/C fibers reinforced polypropylene hybrid composite have been investigated. Treated with MA-g-PP B/C fibers reinforced specimens explored better mechanical properties compared to untreated B/C fibers reinforced polypropylene hybrid composites. Mechanical tests represents that tensile, flexural and impact strength increases with increase in concentration of coupling agent compared to without coupling agent MA-g-PP hybrid composites . B/C fibers reinforced polymer composites exhibited higher tensile, flexural and impact strength at 5% of Banana fiber, 15% of fiber Coir in the presence of 8% of MA-g-PP compared to 4% of MA-g-PP and untreated hybrid composites. The percentage of water absorption in the B/C fibers reinforced polypropylene hybrid composites resisted due to the presence of coupling agent MA-g-PP and thermogravimetry analysis (TGA) also has done.

scholarly journals Dual cholinergic signals regulate daily migration of hematopoietic stem cells and leukocytes

Blood ◽  
2019 ◽  
Vol 133 (3) ◽  
pp. 224-236 ◽  
Author(s):  
Andrés García-García ◽  
Claudia Korn ◽  
María García-Fernández ◽  
Olivia Domingues ◽  
Javier Villadiego ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Nervous System ◽  
Adrenergic Receptor ◽  
Leukocyte Trafficking ◽  
Vascular Cell Adhesion ◽  
Cholinergic Activity ◽  
Vascular Cell ◽  
Hematopoietic Stem ◽  
Stem And Progenitor Cells

AbstractHematopoietic stem and progenitor cells (HSPCs) and leukocytes circulate between the bone marrow (BM) and peripheral blood following circadian oscillations. Autonomic sympathetic noradrenergic signals have been shown to regulate HSPC and leukocyte trafficking, but the role of the cholinergic branch has remained unexplored. We have investigated the role of the cholinergic nervous system in the regulation of day/night traffic of HSPCs and leukocytes in mice. We show here that the autonomic cholinergic nervous system (including parasympathetic and sympathetic) dually regulates daily migration of HSPCs and leukocytes. At night, central parasympathetic cholinergic signals dampen sympathetic noradrenergic tone and decrease BM egress of HSPCs and leukocytes. However, during the daytime, derepressed sympathetic noradrenergic activity causes predominant BM egress of HSPCs and leukocytes via β3–adrenergic receptor. This egress is locally supported by light-triggered sympathetic cholinergic activity, which inhibits BM vascular cell adhesion and homing. In summary, central (parasympathetic) and local (sympathetic) cholinergic signals regulate day/night oscillations of circulating HSPCs and leukocytes. This study shows how both branches of the autonomic nervous system cooperate to orchestrate daily traffic of HSPCs and leukocytes.

scholarly journals Mechanical Properties of a Biocomposite Based on Carbon Nanotube and Graphene Nanoplatelet Reinforced Polymers: Analytical and Numerical Study

2021 ◽  
Vol 5 (9) ◽  
pp. 234
Author(s):  
Marwane Rouway ◽  
Mourad Nachtane ◽  
Mostapha Tarfaoui ◽  
Nabil Chakhchaoui ◽  
Lhaj El Hachemi Omari ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
Mechanical Performance ◽  
Volume Fraction ◽  
Numerical Study ◽  
Turbine Blades ◽  
Natural Fibers ◽  
Computational Method ◽  
Wind Turbine Blades ◽  
Reinforced Polymer ◽  
Analytical Approaches

Biocomposites based on thermoplastic polymers and natural fibers have recently been used in wind turbine blades, to replace non-biodegradable materials. In addition, carbon nanofillers, including carbon nanotubes (CNTs) and graphene nanoplatelets (GNPs), are being implemented to enhance the mechanical performance of composites. In this work, the Mori–Tanaka approach is used for homogenization of a polymer matrix reinforced by CNT and GNP nanofillers for the first homogenization, and then, for the second homogenization, the effective matrix was used with alfa and E-glass isotropic fibers. The objective is to study the influence of the volume fraction Vf and aspect ratio AR of nanofillers on the elastic properties of the composite. The inclusions are considered in a unidirectional and random orientation by using a computational method by Digimat-MF/FE and analytical approaches by Chamis, Hashin–Rosen and Halpin–Tsai. The results show that CNT- and GNP-reinforced nanocomposites have better performance than those without reinforcement. Additionally, by increasing the volume fraction and aspect ratio of nanofillers, Young’s modulus E increases and Poisson’s ratio ν decreases. In addition, the composites have enhanced mechanical characteristics in the longitudinal orientation for CNT- reinforced polymer and in the transversal orientation for GNP-reinforced polymer.

scholarly journals Mechanical Performance Under Various Conditions of 3D Printed Polylactide Composites With Natural Fibers

2021 ◽  
Author(s):  
Karolina E. Mazur ◽  
Aleksandra Borucka ◽  
Paulina Kaczor ◽  
Szymon Gądek ◽  
Stanislaw Kuciel
Keyword(s):  
Elevated Temperatures ◽  
Mechanical Performance ◽  
Natural Fibers ◽  
Crystallization Rate ◽  
Mechanical Tests ◽  
Hydrothermal Degradation ◽  
3D Printed ◽  
The Impact ◽  
Different Levels ◽  
Additive Methods

Abstract In the study, polylactide-based (PLA) composites modified with natural particles (wood, bamboo, and cork) and with different levels of infilling (100%, 80%, and 60%) obtained by additive methods were tested. The effect of type fiber, infill level and crystallization rate on the mechanical properties were investigated by using tensile, flexural, and impact tests. The materials were subjected to mechanical tests carried out at 23 and 80 °C. Furthermore, hydrothermal degradation was performed, and its effect on the properties was analyzed. The addition of natural fillers and different level of infilling result in a similar level of reduction in the properties. Composites made of PLA are more sensitive to high temperature than to water. The decrease in Young's modulus of PLA at 80 °C was 90%, while after 28 days of hydrodegradation ~ 9%. The addition of fibers reduced this decrease at elevated temperatures. Moreover, the impact strength has been improved by 50% for composites with cork particles and for other lignocellulosic composites remained at the same level as for resin.

Essential oil of Citrus lumia Risso: Phytochemical profile, antioxidant properties and activity on the central nervous system

2018 ◽  
Vol 119 ◽  
pp. 407-416 ◽  
Author(s):  
Antonella Smeriglio ◽  
Susanna Alloisio ◽  
Francesco Maria Raimondo ◽  
Marcella Denaro ◽  
Jianbo Xiao ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Essential Oil ◽  
Antioxidant Properties ◽  
The Central Nervous System ◽  
Phytochemical Profile

scholarly journals Polyphenols in the Aqueous Extracts of Garden Thyme (Thymus vulgaris) Chemotypes Cultivated in Hungary

2013 ◽  
Vol 8 (5) ◽  
pp. 1934578X1300800
Author(s):  
Blanka Szilvássy ◽  
Gábor Rak ◽  
Szilvia Sárosi ◽  
Ildikó Novák ◽  
Zsuzsanna Pluhár ◽  
...  
Keyword(s):  
Phenolic Acids ◽  
Rosmarinic Acid ◽  
High Performance ◽  
Screening Method ◽  
Antioxidant Properties ◽  
Syringic Acid ◽  
Thymus Vulgaris ◽  
Aqueous Extracts ◽  
Main Component ◽  
Volatile Aromatic Compounds

Thyme is used worldwide both as a spice and crude drug. In addition, nowadays in the food industry it has increasing significance as a natural antioxidant. Volatile aromatic compounds of thyme have been thoroughly characterized; however, the non-volatile compounds may also contribute to the organoleptic quality and antioxidant properties. The aim of this work is to determine the phenolic acids and to profile the flavonoid compounds in the aqueous extract of two chemotypes of Thymus vulgaris L. Experiments were carried out using high performance liquid chromatography-electrospray ionization-tandem mass spectrometry (HPLC-ESI-MS/MS). Predefined phenolic acids were quantified in untreated and alkaline hydrolyzed aqueous extracts. Flavonoid derivatives were qualitatively analyzed by a non-targeted screening method. Our results showed that among the phenolic acids rosmarinic acid was the main component (882-1677 μg g−1 fresh weight) and in the thymol-type samples the amount of syringic acid and rosmarinic acid was predominantly higher compared with the non-thymol type sample. Apigenin and luteolin were the major flavonoids in the extracts, which were present in the form of hexopyranuronic acid conjugates.

scholarly journals Mechanical Performance of Unstitched and Silk Fiber-Stitched Woven Kenaf Fiber-Reinforced Epoxy Composites

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4801
Author(s):  
Yasir Khaleel Kirmasha ◽  
Mohaiman J. Sharba ◽  
Zulkiflle Leman ◽  
Mohamed Thariq Hameed Sultan
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Mechanical Performance ◽  
Mechanical Test ◽  
Natural Fibers ◽  
Silk Fiber ◽  
Epoxy Composites ◽  
Test Results ◽  
The Impact ◽  
Woven Kenaf

Fiber composites are known to have poor through-thickness mechanical properties due to the absence of a Z-direction binder. This issue is more critical with the use of natural fibers due to their low strength compared to synthetic fibers. Stitching is a through-thickness toughening method that is used to introduce fibers in the Z-direction, which will result in better through-thickness mechanical properties. This research was carried out to determine the mechanical properties of unstitched and silk fiber-stitched woven kenaf-reinforced epoxy composites. The woven kenaf mat was stitched with silk fiber using a commercial sewing machine. The specimens were fabricated using a hand lay-up method. Three specimens were fabricated, one unstitched and two silk-stitched with deferent stitching orientations. The results show that the stitched specimens have comparable in-plane mechanical properties to the unstitched specimens. For the tensile mechanical test, stitched specimens show similar and 17.1% higher tensile strength compared to the unstitched specimens. The flexural mechanical test results show around a 9% decrease in the flexural strength for the stitched specimens. On the other hand, the Izod impact mechanical test results show a significant improvement of 33% for the stitched specimens, which means that stitching has successfully improved the out-of-plane mechanical properties. The outcome of this research indicates that the stitched specimens have better mechanical performance compared to the unstitched specimens and that the decrease in the flexural strength is insignificant in contrast with the remarkable enhancement in the impact strength.

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