Knitted Tube Research Articles

Characterization and promotion of endothelialization of Bombyx mori silk fibroin functionalized with REDV peptide

In the development of small-diameter vascular grafts, it is crucial to achieve early-stage endothelialization to prevent thrombus formation and intimal hyperplasia. Silk fibroin (SF) from Bombyx mori is commonly used for such grafts. However, there is a need to expedite endothelialization post-implantation. In this study, we functionalized SF with Arg-Glu-Asp-Val (REDV) (SF + REDV) using cyanuric chloride to enhance endothelialization. The immobilization of REDV onto SF was confirmed and the amount of immobilized REDV could be calculated by 1H NMR. Furthermore, the conformational changes in Tyr, Ser, and Ala residues in [3-13C]Tyr- and [3-13C]Ser-SF due to REDV immobilization were monitored using 13C solid-state NMR. The REDV immobilized onto the SF film was found to be exposed on the film's surface, as confirmed by biotin-avidin system. Cell culture experiments, including adhesiveness, proliferation, and extensibility, were conducted using normal human umbilical vein endothelial cells (HUVEC) and normal human aortic smooth muscle cells (HAoSMC) on both SF and SF + REDV films to evaluate the impact of REDV on endothelialization. The results indicated a trend towards promoting HUVEC proliferation while inhibiting HAoSMC proliferation. Therefore, these findings suggest that SF + REDV may be more suitable than SF alone for coating small-diameter SF knitted tubes made of SF threads.

Knitted tube reinforced chitosan/β‐cyclodextrin composite ultrafiltration membrane for removing copper ions from water

AbstractIndustrial development has brought about serious water pollution problems, and the removal of heavy metals from water to obtain clean water is essential for human survival. Therefore, in this study, a knitted tube reinforced chitosan (CS)/β‐cyclodextrin (CD) composite ultrafiltration membrane was prepared for the removal of Cu2+ from water by a non‐solvent induced phase separation method, and the membrane forming property of CS was improved by using knitted tubes. The removal of Cu2+ by the composite ultrafiltration membrane followed the Langmuir isothermal model and the pseudo‐second‐order kinetic equation, mainly through the complexation between the amino group on CS and the hydroxyl group on β‐CD and Cu2+. Under static conditions, the removal rate of the prepared ultrafiltration membrane for Cu2+ was 97%, and the removal rate increased with the increase of pH and decreased with the increase of temperature. The removal of Cu2+ by the ultrafiltration membrane during filtration was 100% and the regeneration rate was over 95%. This study provided a practical basis for the separation membrane preparation of CS and provided a perspective for the removal of heavy metals by separation membranes.

Effect of Dry Relaxation on Lengthwise Measurement Deviation of Polyester/Spandex Plated Knitted Tubes after Dyeing

Effect of Dry Relaxation on Lengthwise Measurement Deviation of Polyester/Spandex Plated Knitted Tubes after Dyeing

Interface treatment and performance study on fiber tube reinforced polyvinylidene fluoride hollow fiber membranes

The fiber tube reinforced hollow fiber membranes are widely used in membrane bioreactor (MBR) due to their excellent mechanical and filtered properties. However, the poor adhesive power between fiber tubes and membranes restricted their service life in practice applications. Herein, we supply a facile and feasible surface coating modification methods for optimizing the interfacial bonding ability. The outer surfaces of the braided and knitted tubes were modified with silane coupling agent KH570 and acrylate adhesive before the fiber tube reinforced hollow fiber membranes were fabricated. The effects of different modifiers dosages on the morphology, tensile strength, bursting strength, pure water flux, porosity and mean pore size of the braided and knitted tubes reinforced hollow fiber membranes were evaluated respectively. Moreover, the effects of different modifiers on the fabric tubes with different structure were analysed. The results showed that the optimum dosage of the two modifiers was 3 g/5m. It is revealed that the minute quantities of modifiers applied to the tubes could improve not only the interfacial combination of the reinforced membrane, but also their strength and penetration performance.

Study on Preparation and Separation and Adsorption Performance of Knitted Tube Composite β-Cyclodextrin/Chitosan Porous Membrane.

In order to obtain membranes with both organic separation and adsorption functions, knitted tube composite β-cyclodextrin/chitosan (β-CD/CS) porous membranes were prepared by the non-solvent induced phase separation (NIPS) method using CS and β-CD as a membrane-forming matrix, glutaraldehyde as crosslinking agent to improve water stability, and knitted tube as reinforcement to enhance the mechanical properties. Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), contact angle, water flux, bovine serum albumin (BSA) rejection and tensile test were carried out. The FTIR demonstrated that the β-CD and CS had been successfully crosslinked. With the crosslinking time increased, the membrane structure became denser, the contact angle and the rejection rate increased, while the water flux decreased. The strength and elongation at a break were 236 and 1.7 times higher than these of bare β-CD/CS porous membranes, respectively. The strength of crosslinking membranes increased further. The adsorption performance of composite membranes was investigated for the removal of phenolphthalein (PP) from aqueous solution. The adsorption process followed the Langmuir isotherm model, and the kinetic behavior was accorded with the Double constant equation and the Elovich equation. The adsorption mechanism could be explained by the synergistic effect of host-guest interaction from β-cyclodextrin, non-uniform diffusion and porous network capture.

Tensile and electrical properties of carbon nanotube yarns and knitted tubes in pure or composite form

Carbon Nanotubes (CNTs) have exceptionally high strength and high elastic modulus, as well as good electrical and thermal conductivity. The objective of current research is to develop new lightweight, strong, and conductive materials by using CNTs primarily in pure form. Recently, we have developed a solid-state processing method that enables the CNTs to be assembled into pure yarns and webs, avoiding the problems associated with the presence of a binder, and improving the exploitation of the inherent properties of the individual CNTs. In this paper will report on recent experience with spinning CNT yarns and the effect of twist on selected properties. We also report our results on knitted tubes, in both pure and composite form.

Evaluation of Morphological and Functional Nerve Recovery of Rat Sciatic Nerve with a Hyaff11-Based Nerve Guide

Application of a Hyaff11-based nerve guide was studied in rats. Functional tests were performed to study motor nerve recovery. A withdrawal reflex test was performed to test sensory recovery. Morphology was studied by means of histology on explanted tissue samples. Motor nerve recovery was established within 7 weeks. Hereafter, some behavioral parameters like alternating steps showed an increase in occurence, while others remained stable. Sensory function was observed within the 7 weeks time frame. Nerve tissue had bridged the 10-mm gap within 7 weeks. The average nerve fiber surface area increased significantly in time. In situ degradation of the nerve conduit was fully going on at week 7 and tubes had collapsed by then. At weeks 15 and 21, the knitted tube wall structure was completely surrounded by macrophages and giant cells, and matrix was penetrating the tube wall. We conclude that a Hyaff11-based nerve guide can be used to bridge short peripheral nerve defects in rat. However, adaptations need to be made.

A BIPOTENTIOMETRIC FIA SYSTEM FOR DETERMINATION OF VITAMIN C

A bipotentiometric FIA system has been developed for the determination of vitamin C. The system was a single stream manifold, which consisted of a peristaltic pump, a self made injector with internal loop and two Pt-electrodes connected to a PC by serial ADC or parallel ADC interface card. One of the Ptelectrodes was located in the injector before the internal loop, while the other electrodes at the end of the TEFLON reaction tube. The PC was supported with a self-made software for controlling the pump, signal acquisition, processing, and visualisation, and further peak determination, followed by calibration of standard solutions and calculation of sample concentrations. The above FIA-system configuration was applied to determine vitamin C by the injection of sample solution into a stream of potassium hexacyanoferrate (III) solution. The optimum result was achieved with knitted tube reaction of 0.8 mm i.d., 50 cm length, at flow rate 0,64 ml/minute, and consumed 3.6 ml of carrier solution per five injection, and gave linearity range at 0.001 – 0.100 N vitamin C, with the coefficient of correlation 0.9999, RSD peak to peak better than 3.0% and the error of artificial samples were less than 3.4 %. Key Words : Bipotentiometric-FIA, injector with internal loop, module-program, vitamin C

Evaluation of Morphological and Functional Nerve Recovery of Rat Sciatic Nerve with a Hyaff11‐Based Nerve Guide

Application of a Hyaff11‐based nerve guide was studied in rats. Functional tests were performed to study motor nerve recovery. A withdrawal reflex test was performed to test sensory recovery. Morphology was studied by means of histology on explanted tissue samples. Motor nerve recovery was established within 7 weeks. Hereafter, some behavioral parameters like alternating steps showed an increase in occurence, while others remained stable. Sensory function was observed within the 7 weeks time frame. Nerve tissue had bridged the 10‐mm gap within 7 weeks. The average nerve fiber surface area increased significantly in time. In situ degradation of the nerve conduit was fully going on at week 7 and tubes had collapsed by then. At weeks 15 and 21, the knitted tube wall structure was completely surrounded by macrophages and giant cells, and matrix was penetrating the tube wall. We conclude that a Hyaff11‐based nerve guide can be used to bridge short peripheral nerve defects in rat. However, adaptations need to be made.

Fluorescence detection of cardenolides in reversed-phase high-performance liquid chromatography after post-column derivatization

Methods for the fluorescence derivatization of cardiac glycosides with concentrated acids from TLC are adopted to HPLC for post-column derivatization. The column effluent is blended with concentrated acids in a knitted tube reactor, which enables derivatization with negligible increase in chromatographic peak width. The selectivity of the reaction is temperature-dependent and influenced by the respective acid. Reactivity increases from H 3PO 4→CH 3SO 3H ≡ H 2SO 4. The conversion of digoxigenin, digitoxigenin and their digitoxosides is accelerated by Cu(II) acetate or Co(II) nitrate in H 2SO 4. Combined with a new two-mode, single-column solid-phase sample preparation, cardiac glycoside levels of less than 100 pg/glycoside in 1 ml plasma are detectable.

Long-term results of fourth ventriculo-cisternostomy in complex versus simplex atresias of the fourth ventricle outlets.

Twelve cases of atresia of the fourth ventricle outlets are presented and they are classified into 2 types: simplex versus complex. Fourth ventriculo-cisternostomy is the treatment of choice. Based on the surgical experiences in simplex cases, new technical modifications were developed to make it applicable to the complex cases as well. The advantages and limitations of such operative approaches over other conventional shunt procedures are compared and the long-term postoperative results are listed. Hopefully, the surgical intervention described here may have opened a reasonable method for treating certain cases of the trapped fourth ventricle as a special variant of the complex atresia type. It is important to realize that knitted tubes are categorically unqualified for the surgical use like this.

Limitations to knitted synthetic tubes as vascular prostheses.

Since the report by Voorhees and associates in 1952 of the use of a weave of Vinyon-N as an artery substitute⁷several materials have been used with good results. One of the common disadvantages is the lack of elasticity. To overcome this, Sanger and associates^5,6advocated knitting the grafts and have reported good results with knitted tubes of Orlon. The equivocal results obtained in this laboratory with knitted Orlon tubes replacing segments of the thoracic and abdominal aortas in 24 dogs have prompted this report. <h3>Materials</h3> Knitted Orion tubes * of three types were used. The abdominal aortic grafts were of two types. One was knitted with 48 stitches per inch of a 200 denier Orion (Fig. 1<i>A</i>) and had an air porosity † of 250. The other was knitted with 56 stitches per inch of a 200 denier Orlon and had an air porosity of 76 (Fig.