MECHANICAL CHARACTERIZATION OF SPINAL DURA USING A PD-CONTROLLED BIAXIAL TENSILE TESTER

2020 ◽  
Vol 20 (05) ◽  
pp. 2050023
Author(s):  
ATSUTAKA TAMURA ◽  
WATARU YANO ◽  
DAICHI YOSHIMURA ◽  
SOICHIRO NISHIKAWA
Keyword(s):  
Dura Mater ◽  
Mechanical Response ◽  
Longitudinal Direction ◽  
Mechanical Tests ◽  
Circumferential Direction ◽  
Lumbar Region ◽  
Biaxial Tensile ◽  
Tensile Tester ◽  
Significant Difference ◽  
Upper Thoracic

In this study, we developed an equi-load biaxial tensile tester and applied it to a series of mechanical tests using specimens obtained from the porcine spinal dura mater. The dural sample exhibited a nonlinear and anisotropic behavior as it was more deformable in the longitudinal direction rather than in the circumferential direction at lower strains; i.e., mechanical response of the longitudinal direction was significantly compliant in the Toe region compared to that of the circumferential direction under 1:1 biaxial stretching. However, we have not observed a significant difference with respect to the resultant strain and Young’s modulus between the longitudinal and circumferential directions at higher strains or in the Linear region. Our results also indicated that the upper thoracic region (T1) was relatively compliant compared to the lumbar region (L), where the failure load was almost equal between them because the dural thickness of T1 was five-fold greater than that of L; i.e., spinal dura mater became stiffer and stronger at further distances from the brain. This shows structural effectiveness and may be preferable to mechanically protect the vulnerable spinal cord from externally applied impact loads.

Effect of Anatomical Sites On the Mechanical Properties of Spinal Dura Subjected to Biaxial Stretching

2021 ◽  
Author(s):  
Atsutaka Tamura ◽  
Soichiro Nishikawa
Keyword(s):  
Mechanical Properties ◽  
Dura Mater ◽  
Longitudinal Direction ◽  
Ventral Side ◽  
Dorsal Side ◽  
Tensile Tester ◽  
Material Stiffness ◽  
Cerebrospinal Fluid Leaks ◽  
Physiological Motion

Abstract The spinal cord is encased by spinal meninges called the pia, arachnoid, and dura maters. Among these membranes, the dura mater is the thick and outermost layer and is the toughest and strongest. Thus, mechanical failure of the dura mater can lead to spontaneous cerebrospinal fluid leaks or hypovolemia, resulting in a complication or exacerbation of unfavorable symptoms involved in a mild traumatic brain injury. To develop protective equipment that can help prevent such injuries, accurate characterization of the spinal dura mater is required, especially regarding the mechanical properties at different anatomical sites. In this study, we used an equiload biaxial tensile tester to investigate the mechanical properties of porcine meningeal dura mater along the whole length of the spine. The resultant strain of the dorsal side was greater than that of the ventral side (P < 0.01), while the circumferential direction was significantly stiffer than the longitudinal direction (P < 0.01) at lower strains regardless of the spinal level. We also found that the material stiffness progressively increased from the cervical level to the thoracolumbar level at lower strains, which implies that the dura mater inherently possesses structurally preferred features or functions because the neck requires sufficient flexibility for daily activities. Further, Young's modulus was significantly less on the dorsal side than on the ventral side at higher strains (P < 0.05), suggesting that the dorsal side is readily elongated by spinal flexion even within the range of physiological motion.

Study of effect of waste tire rubber which is a recycling material in production of laminated veneer lumber (LVL) boards

2021 ◽  
pp. 147776062110194
Author(s):  
Kadir Özkaya ◽  
Taner Dizel ◽  
Hasan Özgür Imirzi
Keyword(s):  
Environmental Problem ◽  
Forest Products ◽  
Longitudinal Direction ◽  
Mechanical Tests ◽  
Pinus Silvestris ◽  
Forest Products Industry ◽  
Scotch Pine ◽  
Laminated Veneer Lumber ◽  
Waste Tire ◽  
Different Types

The amount of waste produced by people increases with the increasing population in the world. Especially non-recyclable wastes have become a major environmental problem. Waste tires that emerge as car demands of people increase are one of the non-recyclable wastes. In this study, the usage possibilities of powder rubbers obtained from waste car tires were examined in the production of laminated veneer lumber (LVL) boards, which are preferred as furniture and decoration material in the forest products industry. For this, three different tree species (Scotch Pine— Pinus silvestris L., Oriental Beech— Fagus orientalis L., Stinking Juniper— Juniperus foetidissima Wild.) and two different types of glue (UF and PVAc glues) were used. Waste tire rubbers (WTR) were mixed into the glue in different proportions (0%, 10%, 20%, 30%). Physical (full dry and equilibrium moisture density, contraction in the transversal and longitudinal direction) and mechanical tests (MoR, MoE, bonding resistance) were performed on the LVL samples prepared. According to the results obtained, it has been seen that the mixtures of 10% and 20% WTR increase the LVL resistance. An eco-friendly building material has been obtained by using WTR produced from waste car tires in production of LVL.

scholarly journals Effect of alkaline solutions on the tensile properties of glass-polyester pipes

2011 ◽  
pp. 185-195 ◽  
Author(s):  
Slavisa Putic ◽  
Marina Stamenovic ◽  
Jelena Petrovic ◽  
Marko Rakin ◽  
Bojan Medjo
Keyword(s):  
Tensile Properties ◽  
Construction Materials ◽  
Ammonium Hydroxide ◽  
Longitudinal Direction ◽  
Testing Procedure ◽  
Circumferential Direction ◽  
Process Equipment ◽  
Alkaline Solutions ◽  
Ph Values ◽  
Definite Structure

Construction materials, traditionally used in process equipment, are today successfully replaced by composite materials. Hence, many pipes are made of these materials. The subject of this study was the influence of liquids on the state of stresses and tensile strengths in the longitudinal and circumferential direction of glass-polyester pipes of a definite structure and known fabrication process. These analyses are of great importance for the use of glass-polyester pipes in the chemical industry. The tensile properties (the ultimate tensile strength and the modulus of elasticity) were tested and determined for specimens cut out of the pipes; flat specimens for the tensile properties in the longitudinal direction and ring specimens for the tensile properties in the circumferential direction. First, the tension test was performed on virgin samples (without the influence of any liquid), to obtain knowledge about the original tensile properties of the material composite studied. Subsequently, the specimens were soaked in alkaline solutions: sodium hydroxide (strong alkali) and ammonium hydroxide (weak alkali). These solutions were selected because of their considerable difference in pH values. The specimens and rings were left for 3, 10, 30 and 60 days in each liquid at room temperature. Then, the samples were tested on tension by the standard testing procedure. A comparison of the obtained results was made based on the pH values of the aggressive media in which the examined material had been soaked, as well as based on the original tensile properties and the number of days of treatment. Micromechanical analyses of sample breakage helped in the elucidation of the influence of the liquids on the structure of the composite pipe and enabled models and mechanisms that produced the change of strength to be proposed.

scholarly journals Optimal Design and Testing of a Thermoplastic Pressurized Passenger Door Manufactured Using Thermoforming

Polymers ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 3394
Author(s):  
Roman Růžek ◽  
Josef Křena ◽  
Radek Doubrava ◽  
Josef Tkadlec ◽  
Martin Kadlec ◽  
...  
Keyword(s):  
Numerical Simulations ◽  
Impact Damage ◽  
Research Work ◽  
Variable Cross Section ◽  
Mechanical Tests ◽  
Point Of View ◽  
Topological Optimization ◽  
Variable Cross ◽  
Thermoplastic Resin ◽  
Significant Difference

The present paper documents and discusses research work associated with a newly designed passenger door structure demonstrator. The composite structure was manufactured from carbon-fiber-reinforced thermoplastic resin. A composite frame with a variable cross-section was designed, optimized, and fabricated using thermoforming technology. Both numerical simulations and experiments supported structural verification according to the damage tolerance philosophy; i.e., impact damage is presented. The Tsai-Wu and maximal stress criteria were used for damage analysis of the composite parts. Topological optimization of the metal hinges from the point of view of weight reduction was used. All expected parameters and proposed requirements of the mechanical properties were proved and completed. The door panel showed an expected numerically evaluated residual strength (ultimate structure load) as well as meeting airworthiness requirements. No impact damage propagation in the composite parts was observed during mechanical tests, even though visible impact damage was introduced into the structure. No significant difference between the numerical simulations and the experimentally measured total deformation was observed. Repeated deformation measurements during fatigue showed a nonlinear structure behavior. This can be attributed to the relaxation of thermoplastics.

scholarly journals Biaxial Tensile Tester for Flat Plates

1968 ◽  
Vol 17 (175) ◽  
pp. 356-360 ◽  
Author(s):  
Kazuhiko SAKAGUCHI ◽  
Sueo KAWABATA ◽  
Hiromichi KAWAI ◽  
Nobuo HAZAMA
Keyword(s):  
Flat Plates ◽  
Biaxial Tensile ◽  
Tensile Tester

scholarly journals Experimental investigations of the human oesophagus: anisotropic properties of the muscular layer in large deformation

2021 ◽  
Author(s):  
Ciara Durcan ◽  
Mokarram Hossain ◽  
Gregory Chagnon ◽  
Djordje Peric ◽  
Lara Bsiesy ◽  
...  
Keyword(s):  
Strain Rate ◽  
Ex Vivo ◽  
Longitudinal Direction ◽  
Tensile Tests ◽  
Endoscopic Biopsy ◽  
Circumferential Direction ◽  
Experimental Investigations ◽  
Uniaxial Tensile ◽  
Rate Dependency ◽  
Muscular Layer

Technological advancements in the field of robotics have led to endoscopic biopsy devices able to extract diseased tissue from between the layers of the gastrointestinal tract. Despite this, the layer-dependent properties of these tissues have yet to be mechanically characterised using human tissue. In this study, the ex vivo mechanical properties of the passive muscularis propia layer of the human oesophagus were extensively investigated. For this, a series of uniaxial tensile tests were conducted. The results displayed hyperelastic behaviour, while the differences between loading the tissue in both the longitudinal and circumferential directions showcased its anisotropy. The anisotropy of the muscular layer was present at different strain rates, with the longitudinal direction being consistently stiffer than the circumferential one. The circumferential direction was found to have little strain-rate dependency, while the longitudinal direction results suggest pronounced strain-rate-dependent behaviour. The repeated trials showed larger variation in terms of stress for a given strain in the longitudinal direction compared to the circumferential direction. The possible causes of variation between trials are discussed, and the experimental findings are linked to the histological analysis which was carried out via various staining methods. Finally, the direction-dependent experimental data was simulated using an anisotropic, hyperelastic model.

scholarly journals Experimental skin wound treatment with Copaifera langsdorffii Desf Kuntze (Leguminosae) extract and oil-resin in horses

2020 ◽  
Vol 57 (3) ◽  
pp. e166095
Author(s):  
Débora Perrone Kauer ◽  
Juliana de Moura Alonso ◽  
Lucas Fernando Sergio Gushiken ◽  
Marivane Lemos ◽  
Carlos Roberto Padovani ◽  
...  
Keyword(s):  
Wound Healing ◽  
Small Area ◽  
Healing Process ◽  
Skin Lesions ◽  
Lumbar Region ◽  
Skin Wounds ◽  
Native Plant ◽  
Chronic Inflammatory Response ◽  
Significant Difference ◽  
Copaifera Langsdorffii

Copaifera langsdorffii is a Brazilian native plant that is used for wound healing or as an anti-inflammatory agent. Non-healing wounds are an important health problem, particularly in horses, because they can cause the animal invalidity or even lead to death. In addition, horses respond to skin wounds with chronic inflammatory response and intense wound granulation, thereby delaying the healing process. By this way, our aim was to evaluate the healing potential of Copaifera langsdorffii hydroalcoholic extract (HE) and oil-resin creams (OR) in horse skin wounds. Four wounds were performed bilaterally in the lumbar region of six horses with a 2 cm punch and treated daily with the respective treatments: saline solution, vehicle, 10% HE creams or 10% OR cream. Daily planimetry analyses were performed to measure the wound area and clinical parameters. In four different experimental periods (3, 7, 14 and 21 d), wound biopsies were removed and used for microscopic analyses. SS wounds presented a significant small area at day 3 and 7, OR wounds presented significant small area in comparison with HE at 14 d, and no significant difference was observed between treatments at 21 d. A better microscopic and clinical healing activity of HE and OR was identified in comparison with the controls. The OR group showed better healing quality, specifically after 7 d of treatment. Therefore, Copaifera langsdorffii formulations demonstrated their wound healing potential in horse skin lesions, exhibiting an improvement of the macro- and microscopic parameters.

Treatment of fresh thoracolumbar vertebral burst fracture based on intraoperative CT scan

2020 ◽  
Author(s):  
yuwei li ◽  
wei cui ◽  
Peng Zhou ◽  
Cheng Li ◽  
Wei Xiao ◽  
...  
Keyword(s):  
Treatment Group ◽  
Ct Scan ◽  
Cobb Angle ◽  
Dura Mater ◽  
Spinal Canal ◽  
Control Group ◽  
Intraoperative Ct ◽  
Bleeding Volume ◽  
Significant Difference ◽  
Cord Injury

Abstract ObjectiveTo evaluate the value of intraoperative CT scanning in the treatment of fresh thoracolumbar burst fractures .MethodThe data of patients with thoracolumbar fractures from January 2008 to January 2015 were analyzed retrospectively,79 cases were treatment group which were treated with intraoperative CT scan and decompression mode was determined according to CT scan results during the period from October 2012 to January 2015; 82 patients as the observation group were treated without intraoperative CT scan and direct laminectomy were performed during the period from January 2008 to October 2012. In the treatment group, it is no further decompression of the spinal canal when the CT showed a reduction of the fracture block into the spinal canal, If the intraoperative CT showed that the fractures still occupied the spinal dura mater according to the three-dimensional CT information, The position and the size of the fracture of the spinal canal were determined, and the unilateral laminectomy was performed corresponding to the position of the lamina and intervertebral ligamentum flavum. The operative time, bleeding volume, neurological function, height of the anterior vertebral compression and Cobb angle were compared between the two groups.ResultIn the treatment group, CT scan showed 48 cases (60.8%) entered the spinal canal fracture completely or basically reset .31 cases (39.2%) still occupied the spinal canal compression spinal dura mater. There were significant differences in the operation time and bleeding volume between the two groups. The treatment group was less than the control group. There was no infection, secondary spinal cord injury, loose fixation and other complications. There was no difference in the ASIA classification before and after operation. The anterior vertebral height and COBB angle of the two groups were significantly improved compared with those before operation. There was no significant difference between the two groups in the postoperative height and COBB angle, but after 2 years the difference was statistically significant between the two groups, to retain the rear ligament complex treatment group was significantly better than the control group.ConclusionPatients of thoracolumbar vertebral fracture in hyperextension position combined with internal fixation can achieve good correction effect. Orthopedic postoperative CT scan and according to the results of the scan precision treatment can simplify the operation, there was no difference in clinical efficacy compared with total laminectomy, but some patients avoid the spinal canal decompression and part were treated by small fenestration laminectomy decompression, which is conducive to the protection of spinouts ligament complex integrity.

scholarly journals Mechanical Characterization of Nanocomposite Joints Based on Biomedical Grade Polyethylene under Cyclical Loads

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2681
Author(s):  
Annamaria Visco ◽  
Cristina Scolaro ◽  
Antonino Quattrocchi ◽  
Roberto Montanini
Keyword(s):  
Titanium Dioxide ◽  
Mechanical Response ◽  
Mechanical Characterization ◽  
Laser Light ◽  
Mechanical Tests ◽  
Fatigue Tests ◽  
Weight Content ◽  
Percentage Weight ◽  
Static Mechanical

Polymeric joints, made of biomedical polyethylene (UHMWPE) nanocomposite sheets, were welded with a diode laser. Since polyethylene does not absorb laser light, nanocomposites were prepared containing different percentages by weight of titanium dioxide as it is a laser absorbent. The joints were first analyzed with static mechanical tests to establish the best percentage weight content of filler that had the best mechanical response. Then, the nanocomposites containing 1 wt% titanium dioxide were selected (white color) to be subjected to fatigue tests. The experimental results were also compared with those obtained on UMMWPE with a different laser light absorbent nano filler (carbon, with greater laser absorbing power, gray in color), already studied by our research team. The results showed that the two types of joints had an appreciable resistance to fatigue, depending on the various loads imposed. Therefore, they can be chosen in different applications of UHMWPE, depending on the stresses imposed during their use.

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