Preparation and characterization of a polyvinyl alcohol/polyacrylamide hydrogel vascular graft reinforced with a braided fiber stent

2019 ◽  
Vol 90 (13-14) ◽  
pp. 1537-1548 ◽  
Author(s):  
Mei-yi Xing ◽  
Cheng-long Yu ◽  
Yu-fen Wu ◽  
Lu Wang ◽  
Guo-ping Guan
Keyword(s):  
Tensile Strength ◽  
Polyvinyl Alcohol ◽  
Vascular Graft ◽  
Small Diameter ◽  
Dynamic Compliance ◽  
Clinical Applications ◽  
Polyacrylamide Hydrogel ◽  
Mass Ratio ◽  
Overall Performance

A PVA/PAAm (polyvinyl alcohol/polyacrylamide) hydrogel vascular graft reinforced by a braided fiber stent was prepared in the present work, and a series of characterizations were carried out for evaluating the comprehensive performance of the reinforced hydrogel vascular graft (RHVG), including the morphology, the mechanical properties and the biocompatibility. The results show that hydrogel with a mass ratio of 5:8 (PVA:PAAm) is the best candidate for developing an implantation-oriented vascular graft, whose overall performance is the closest to the requirements of clinical applications. The surface of the PVA/PAAm hydrogel is smooth, and the porous structure is uniform and stable. When the longitudinal strain of the RHVG was 50%, the tensile strength reached 905.6 ± 63.1 kPa, much higher than that of a swine common carotid artery (185 kPa). Moreover, the circumferential tensile strength was significantly enhanced by the integration of the stent, and the circumferential compression recovery reached 93.4 ± 6.7%, showing satisfactory structural stability. Furthermore, the suture retention force approached (9.89 ± 0.64 N), higher than that of a canine femoral artery (7.90 ± 0.36 N). More importantly, the radial dynamic compliance reached 3.11 ± 0.09% under testing pressure of 80–120 mmHg, which is 6.9 times that of a commercial expanded polytetrafluoroethylene vascular graft. Lastly, the RHVG has satisfying cytocompatibility and a low hemolysis rate. In summary, the present work may pave the way for developing a novel small-diameter vascular graft for clinical implantation.

Characterization of silk sponge in the wet state using13C solid state NMR for development of a porous silk vascular graft with small diameter

RSC Advances ◽  
2014 ◽  
Vol 4 (9) ◽  
pp. 4427-4434 ◽  
Author(s):  
Tetsuo Asakura ◽  
Toshiki Saotome ◽  
Derya Aytemiz ◽  
Haruka Shimokawatoko ◽  
Takahito Yagi ◽  
...  
Keyword(s):  
Solid State ◽  
Solid State Nmr ◽  
Vascular Graft ◽  
Small Diameter

Development and Biomechanical Characterization of a Novel Bilayer Vascular Graft

2010 ◽  
Author(s):  
Krishna Madhavan ◽  
Walter Bonani ◽  
Craig Lanning ◽  
Wei Tan
Keyword(s):  
Blood Vessel ◽  
Vascular Graft ◽  
Bypass Surgery ◽  
Small Diameter ◽  
Native Artery ◽  
Vessel Lumen ◽  
Unmet Demand ◽  
Tissue Engineered Blood Vessels ◽  
Synthetic Grafts

Vascular grafts are currently used to treat cardiovascular diseases such as arthrosclerosis by bypass surgery and as vascular access in hemodialysis [1]. There are a number of types of grafts including autologous vessels (such saphenous vein), synthetic grafts (such as expanded polytetrafluoroethylene) and tissue engineered blood vessels. Currently synthetic grafts are most commonly used as blood vessel replacements and there are a number of problems associated with them. One main impediment is that these grafts are not suitable for small-diameter (less than 6mm) vessel replacement [1, 2], due to high occlusion rates. The major concern over the other alternatives such as autologous vessels and tissue engineered products is their availability. Thus, new approaches to constructing biomimetic small-diameter blood vessel equivalents, that are immediately available, may address the unmet demand in this area. Therefore, we have designed a novel bilayer vascular construct which is made up of a nanofibrous intimal-equivalent as thromboresistant vessel lumen and a mimetic extracellular matrix (ECM) as medial-equivalent for smooth muscle cells (SMC) from native artery to invade and remodel the ECM.

Preparation and Characterization of Alginate/Polyvinyl Alcohol Composite Fibers Containing Copper Ions

2013 ◽  
Vol 652-654 ◽  
pp. 1562-1565 ◽  
Author(s):  
Jing Guo ◽  
Qian He Chen ◽  
Yu Yan Zhang ◽  
Yu Mei Gong ◽  
Hong Zhang
Keyword(s):  
Tensile Strength ◽  
Polyvinyl Alcohol ◽  
Copper Ions ◽  
Fiber Surface ◽  
Coagulation Bath ◽  
Wet Spinning ◽  
Composite Fibers ◽  
Pseudoplastic Fluid ◽  
Cu Ions

Alginate/polyvinyl alcohol (PVA) composite fibers containing copper ions were prepared by wet spinning. The spinning solution and manufacturing process were researched. The composite fibers were characterized by Tensile Strength Tester, SEM and TGA. This report shows that the spinning solution is a typical kind of pseudoplastic fluid. Adding boric acid to coagulation bath and putting Cu ions into composite fibers can improve the strength. The structure of composite fibers with Cu ions is denser and there are grooves on the fiber surface. In addition, the thermal property of composite fibers is steady.

Fabrication and characterization of a novel compliant small-diameter PET/PU/PCL triad-hybrid vascular graft

2020 ◽  
Vol 15 (5) ◽  
pp. 055004
Author(s):  
Nafiseh Jirofti ◽  
Davod Mohebbi-Kalhori ◽  
Abdolreza Samimi ◽  
Afra Hadjizadeh ◽  
Gholam Hossein Kazemzadeh
Keyword(s):  
Vascular Graft ◽  
Small Diameter ◽  
Fabrication And Characterization

Applications of SIMS to electronic materials and devices

1992 ◽  
Vol 50 (2) ◽  
pp. 1682-1683
Author(s):  
S.F. Corcoran
Keyword(s):  
Depth Distribution ◽  
Secondary Ion Mass Spectrometry ◽  
Semiconductor Device ◽  
Electronic Materials ◽  
Profile Analysis ◽  
Semiconductor Industry ◽  
Small Diameter ◽  
Depth Resolution ◽  
Detection Sensitivity

Over the past decade secondary ion mass spectrometry (SIMS) has played an increasingly important role in the characterization of electronic materials and devices. The ability of SIMS to provide part per million detection sensitivity for most elements while maintaining excellent depth resolution has made this technique indispensable in the semiconductor industry. Today SIMS is used extensively in the characterization of dopant profiles, thin film analysis, and trace analysis in bulk materials. The SIMS technique also lends itself to 2-D and 3-D imaging via either the use of stigmatic ion optics or small diameter primary beams.By far the most common application of SIMS is the determination of the depth distribution of dopants (B, As, P) intentionally introduced into semiconductor materials via ion implantation or epitaxial growth. Such measurements are critical since the dopant concentration and depth distribution can seriously affect the performance of a semiconductor device. In a typical depth profile analysis, keV ion sputtering is used to remove successive layers the sample.

A Possible Basis for Nondestructive Characterization of Ropes of Nylon 6

1997 ◽  
Vol 503 ◽  
Author(s):  
H. Jiang ◽  
M. K. Davis ◽  
R. K. Eby ◽  
P. Arsenovic
Keyword(s):  
Tensile Strength ◽  
Service Life ◽  
Fiber Diameter ◽  
Structural Parameters ◽  
Crystal Form ◽  
Nylon 6 ◽  
Remaining Service Life ◽  
Nondestructive Characterization ◽  
Fractional Content

ABSTRACTPhysical properties and structural parameters have been measured for ropes of nylon 6 as a function of the number of use operations. The fractional content of the α crystal form, sound velocity, birefringence, tensile strength and length all increase systematically and significantly with increasing the number of use operations. The fractional content of the γ crystal form and fiber diameter decrease with use. These trends indicate that the measurement of such properties and structural parameters, especially the length, provide a possible basis for establishing a reliable, rapid, and convenient nondestructive characterization method to predict the remaining service life of nylon 6 ropes.

Highly Fluorescent Au25-xAgx Nanoclusters Protected with Poly(ethylene glycol) - and Zwitterion-Modified Thiolate Ligands

2018 ◽  
Author(s):  
Dinesh Mishra ◽  
Sisi Wang ◽  
Zhicheng Jin ◽  
Eric Lochner ◽  
Hedi Mattoussi
Keyword(s):  
Quantum Yield ◽  
Near Infrared ◽  
Small Diameter ◽  
Binding Energies ◽  
Thiolate Ligands ◽  
Nir Emission ◽  
Thiolate Complexes ◽  
Long Lifetime ◽  
Poly Ethylene

<p>We describe the growth and characterization of highly fluorescing, near-infrared-emitting nanoclusters made of bimetallic Au<sub>25-x</sub>Ag<sub>x</sub> cores, prepared using various monothiol-appended hydrophobic and hydrophilic ligands. The reaction uses well-defined triphenylphosphine-protected Au<sub>11</sub> clusters (as precursors), which are reacted with Ag(I)-thiolate complexes. The prepared nanoclusters are small (diameter < 2nm, as characterized by TEM) with emission peak at 760 nm and long lifetime (~12 µs). The quantum yield measured for these materials was 0.3 - 0.4 depending on the ligand. XPS measurements show the presence of both metal atoms in the core, with measured binding energies that agree with reported values for nanocluster materials. The NIR emission combined with high quantum yield, small size and ease of surface functionalization afforded by the coating, make these materials suitable to implement investigations that address fundamental questions and potentially useful for biological sensing and imaging applications.<br></p>

CARPENTER CUSTOM 475

Alloy Digest ◽  
2006 ◽  
Vol 55 (9) ◽  
Keyword(s):  
Tensile Strength ◽  
Stainless Steel ◽  
Corrosion Resistance ◽  
Small Diameter ◽  
High Strength ◽  
Heat Treating ◽  
Good Corrosion Resistance ◽  
Technology Corporation ◽  
Peak Aged ◽  
Carpenter Technology Corporation

Abstract Custom 475 stainless is a premium melted, high-strength, martensitic, precipitation-hardenable stainless steel. It provides good corrosion resistance and was designed to achieve a tensile strength up to 2000 MPa (290 ksi), combined with good toughness and ductility when in the H975 condition, peak aged at 525 deg C (975 deg F). Other combinations of strength are possible by applying aging temperatures up to 595 deg C (1100 deg F). The alloy is available in strip, wire, and small diameter bar. This datasheet provides information on composition, physical properties, hardness, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, and machining. Filing Code: SS-974. Producer or source: Carpenter Technology Corporation.

Preparation and Characterization of β-glucosidase Films for Stabilization and Handling in Dry Configurations

2020 ◽  
Vol 21 (8) ◽  
pp. 741-747
Author(s):  
Liguang Zhang ◽  
Yanan Shen ◽  
Wenjing Lu ◽  
Lengqiu Guo ◽  
Min Xiang ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Protein Function ◽  
Protein Stabilization ◽  
Functional Protein ◽  
Elongation At Break ◽  
Gelatin Films ◽  
The Stability ◽  
And Function ◽  
General Method

Background: Although the stability of proteins is of significance to maintain protein function for therapeutical applications, this remains a challenge. Herein, a general method of preserving protein stability and function was developed using gelatin films. Method: Enzymes immobilized onto films composed of gelatin and Ethylene Glycol (EG) were developed to study their ability to stabilize proteins. As a model functional protein, β-glucosidase was selected. The tensile properties, microstructure, and crystallization behavior of the gelatin films were assessed. Result: Our results indicated that film configurations can preserve the activity of β-glucosidase under rigorous conditions (75% relative humidity and 37°C for 47 days). In both control films and films containing 1.8 % β-glucosidase, tensile strength increased with increased EG content, whilst the elongation at break increased initially, then decreased over time. The presence of β-glucosidase had a negligible influence on tensile strength and elongation at break. Scanning electron-microscopy (SEM) revealed that with increasing EG content or decreasing enzyme concentrations, a denser microstructure was observed. Conclusion: In conclusion, the dry film is a promising candidate to maintain protein stabilization and handling. The configuration is convenient and cheap, and thus applicable to protein storage and transportation processes in the future.

Fabrication and Characterization of Biocomposite Using Grewia Optiva Fibre (i.e. Bhimal) Reinforced Polyvinyl Alcohol (PVA)

2015 ◽  
Vol 1105 ◽  
pp. 51-55 ◽  
Author(s):  
K.M. Gupta ◽  
Kishor Kalauni
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Natural Fibre ◽  
Fabrication Method ◽  
View Point ◽  
Engineering Material ◽  
Fibre Composites ◽  
Grewia Optiva ◽  
Fabrication And Characterization

Bhimal fibres are quite a newer kind of bio-degradable fibres. They have never been heard before in literatures from the view point of their utility as engineering material. These fibres have been utilized for investigation of their properties. Characterization of this fibre is essential to determine its properties for further use as reinforcing fibre in polymeric, bio-degradable and other kinds of matrix. With this objective, the fabrication method and other mechanical properties of Bhimal-reinforced-PVA biocomposite have been discussed. The stress-strain curves and load-deflection characteristics are obtained. The tensile, compressive, flexure and impact strengths have been calculated. The results are shown in tables and graphs. The results obtained are compared with other existing natural fibre biocomposites. From the observations, it has been concluded that the tensile strength of Bhimal-reinforced-PVA biocomposite is higher than other natural fibre composites. Hence these can be used as reinforcement to produce much lighter weight biocomposites.

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