Bio-Medical Materials and Engineering - Volume 29, issue 5
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The aim of
Bio-Medical Materials and Engineering is to promote the welfare of humans and to help them keep healthy. This international journal is an interdisciplinary journal that publishes original research papers, review articles and brief notes on materials and engineering for biological and medical systems.
Articles in this peer-reviewed journal cover a wide range of topics, including, but not limited to: Engineering as applied to improving diagnosis, therapy, and prevention of disease and injury, and better substitutes for damaged or disabled human organs; Studies of biomaterial interactions with the human body, bio-compatibility, interfacial and interaction problems; Biomechanical behavior under biological and/or medical conditions; Mechanical and biological properties of membrane biomaterials; Cellular and tissue engineering, physiological, biophysical, biochemical bioengineering aspects; Implant failure fields and degradation of implants. Biomimetics engineering and materials including system analysis as supporter for aged people and as rehabilitation; Bioengineering and materials technology as applied to the decontamination against environmental problems; Biosensors, bioreactors, bioprocess instrumentation and control system; Application to food engineering; Standardization problems on biomaterials and related products; Assessment of reliability and safety of biomedical materials and man-machine systems; and Product liability of biomaterials and related products.
Abstract: Alzheimer is a degenerative disorder that attacks neurons, resulting in loss of memory, thinking, language skills, and behavioral changes. Computer-aided detection methods can uncover crucial information recorded by electroencephalograms. A systematic literature search presents the wavelet transform as a frequently used technique in Alzheimer’s detection. However, it requires a defined basis function considered a significant problem. In this work, the concept of empirical mode decomposition is introduced as an alternative to process Alzheimer signals. The performance of empirical mode decomposition heavily relies on a parameter called threshold. In our previous works, we found that the existing thresholding techniques were not…able to highlight relevant information. The use of Tsallis entropy as a thresholder is evaluated through the combination of empirical mode decomposition and neural networks. Thanks to the extraction of better features that boost the classification accuracy, the proposed approach outperforms the state-of-the-art in terms of peak signal to noise ratio and root mean square error. Hence, our methodology is more likely to succeed than methods based on other landmarks such as Bayes, Normal and Visu shrink. We finally report an accuracy rate of 80%, while the aforementioned techniques only yield performances of 65%, 60% and 40%, respectively.
Abstract: Adipose tissue-derived stromal cells (ADSCs) contain lineage-committed progenitor cells that have the ability to differentiate into various cell types that may be useful for autologous cell transplantation to correct defects of skin, adipose, cartilage, bone, tendon, and blood vessels. The multipotent characteristics of ADSCs, as well as their abundance in the human body, make them an attractive potential resource for wound repair and applications to tissue engineering. ADSC transplantation has been used in combination with biomaterials, including cell sheets, hydrogel, and three-dimensional (3D) scaffolds based on chitosan, fibrin, atelocollagen, and decellularized porcine dermis, etc. Furthermore, low molecular weight heparin/protamine nanoparticles…(LH/P NPs) have been used as an inducer of ADSC aggregation. The tissue engineering potential of these biomaterials as cell carriers is increased by the synergistic relationship between ADSCs and the biomaterials, resulting in the release of angiogenic cytokines and growth factors. In this review article, we describe the advantages of ADSC transplantation for tissue engineering, focusing on biomaterials as cell carriers which we have studied.
Abstract: The incidence of heart disease increases with age. The typical method of monitoring arrhythmia is to use a body patch type sensor with a wet electrode. Even though this sensor is easy to use, it has several disadvantages such as problems caused by wet electrodes in tissues when they are monitored for long periods. Thus, a monitoring sensor integrated into clothes with a dry electrode is proposed. In this study, we developed a smart outdoor shirt equipped with a dry electrode electrocardiogram (ECG) sensor for a cardiac arrhythmia computer-aided diagnosis system. The sensor can be inserted in a console close…to the chest, charged, used to communicate wirelessly, and can be connected to a smartphone application. According to experiments, the ECG signals measured by the smart shirt indicated that 97.5 ± 1% of the signals could be measured in an immobile state and at least 85.2 ± 2% of the signals could be measured during movement. In addition, we propose a computer-aided diagnosis system for detecting cardiac arrhythmia. It was determined through experiments that the system can detect arrhythmia with an accuracy of 98.2 ± 2%.
Keywords: Cardiovascular devices, sports instrumentation and devices, sensors/actuators
Abstract: The crack propagation behavior near the initial crack were studied under the compact tension (CT) fracture toughness experiments test on bovine hip bone joint specimens. The bone specimens were prepared according to ASTM E-399 for plain fracture toughness tests. The specimens were cut from the hip joint both in the longitudinal and transverse direction to the collagen fiber orientation in the bone. The precrack or initial crack “a” were produced parallel and vertical to the lontudinal axis of bone in the longitudinal and transverse specimens respectively. The specimens were tested in the universal testing machine for finding fracture toughness and…crack propagation behavior due to different orientation of bone fibers. A camera attached to the machine recorded the crack propagation process. The results show a different crack propagation behavior in longitudinal specimens and transverse specimens. The toughness of the bone consistently changes with age both in longitudinal and transverse direction. Our experimental data matched with the previous published research.
Abstract: BACKGROUND: Various techniques have been developed in the treatment of fractures. One of these techniques is the internal fixation, which has an important place in practice. OBJECTIVE: In this study, fractured tibia bone has been treated with implants as numerically to investigate the stress behavior and the effect of plate material, shape and dimensions under pressure load. METHODS: The outer part of the bone is chosen as orthotropic and the inner part is chosen as isotropic material. The plate has been modeled to take the form of the bone surface and the finite element method has…been used for numerical analysis. The effect of stress on bones and implants has been examined for 1% healing by changing the plate length, plate width and plate material. RESULTS: It has been observed that the increase in plate length decreases cortical bone stress until a specific length. On the other hand, the increase in plate width has increased the stress on the bone. CONCLUSIONS: It is important to form the appropriate plate surface to the bone surface in terms of compliance with the bones.
Keywords: Internal fixation, implant, finite element analysis, crack, tibia
Abstract: The rehabilitation squeeze ball is a popular device to help strengthen the hand, fingers and forearm muscles. The distributions of the contact pressure in the interface between the therapy ball and hand/fingers can affect the joint moment of each of the individual fingers, thereby affecting rehabilitation effects. In the current study, we evaluated the contact force distributions on the fingers when gripping a spherical object. Eight female adults [age 29 (9.1) years, mass 64.6 (7.1) kg, height 163.5 (1.9) cm, hand length 17.2 (0.7) cm] participated in the study. Contact force sensors were attached to the middle of the palmar surfaces of the…distal, middle, and proximal phalanges of the four fingers in the longitudinal direction. In order to evaluate the effects of the ball stiffness on the contact force distributions on the fingers, subjects were requested to perform quasi-static gripping on a standard tennis ball and on a rehabilitation ball. The tennis ball is much stiffer and experiences smaller deformation under compression compared to the rehabilitation ball. We analyzed the force share among the distal, middle, and proximal finger segments, when subjects gripping balls of different stiffnesses (tennis ball vs. rehabilitation ball) and at three different grip efforts. Our results indicated that the grip force is contributed about 60% and 40% by the middle/ring fingers and by the index/little fingers, respectively. These characteristics are independent of the grip force levels and stiffness of the contact surface.
Abstract: BACKGROUND: Cellular treatments using mesenchymal stem cells (MSCs) cultured in 3D conditions constitute a solution to the classical surgery in treating abdominal aortic aneurysm (AAA). The recurrent question is: how this type of biotherapy changes the mechanical behavior of artery? METHODS: Experiments measurements based on xenograft rat model showed that the proposed cellular treatment leads to a decreasing radius and length of the AAA during its growth. An inverse finite element method was used to investigate the mechanical hyperelastic behavior of the AAA in the untreated case compared to the treated one. RESULTS: Although AAA leads…a loss anisotropy while the cellular treatment does not restore it, it was shown that the stiffness of the arterial wall was improved. The numerical analysis of the stress distributions permitted to localize the stress concentration through the arterial wall and the probable zone of the rupture of the aneurysm developed from the xenograft rat model. CONCLUSIONS: The treatment of AAA with MSCs cultured in a 3D conditions constitutes a new challenge. Based on xenograft rat model, this study shows the potential of this cellular treatment to reduce the variation of the growth, the stiffness and the stress distributions.
Keywords: Abdominal aortic aneurysm, cellular therapy, inverse finite element method, loss of anisotropy
Abstract: BACKGROUND: Medial unicompartmental knee arthroplasty (UKA) could be concerned with wear of the cartilage or the wear in the polyethylene (PE) insert. Mechanical alignment determines the biomechanical effect in the long term. However, previous computational studies all found that femoral and tibial components alignment in the UKA were rare, and the results varied. OBJECTIVE: The purpose of this study was to evaluate the biomechanical effect of the femoral and tibial component coronal alignment in varus and valgus conditions through computational simulation. METHODS: A three-dimensional finite element model of the intact knee was constructed from medical image…data of one healthy subject. A medial UKA model of neutral position and various coronal components was developed from the intact knee joint model. The tibial varus-femoral valgus and tibial valgus-femoral varus conditions were analyzed with parallel component angles of 3°, 6° and 9° by using validated finite element models. We considered the contact stresses in the PE inserts and articular cartilage and the force on collateral ligament under gait cycle condition. RESULTS: Compared to the contact stress in the neutral position model, the contact stress on the PE insert increased in both tibial varus-femoral valgus and tibial valgus-femoral varus models. These trends were also observed in the case of the articular cartilage in remain compartment. However, the contact stress on the PE insert and articular cartilage increased largely in the tibial valgus-femoral varus model than in the tibial varus-femoral valgus model. The forces on the medial and lateral collateral ligaments increased in the tibial valgus-femoral varus model, whereas in the tibial varus-femoral valgus model, the forces decreased compared to the forces in the neutral position. The force on the anterior lateral ligament and popliteofibular ligament increased in the tibial varus-femoral valgus model as compared to the neutral position. CONCLUSIONS: Our study suggests that neutral alignment or less than 3° tibial varus-femoral valgus alignment in the coronal plane can be recommended in medial UKA to reduce the postoperative complications and to enhance the life expectancy of implants.
Abstract: This study aimed to investigate the in vivo tissue response of the Biosilicate® scaffolds in a model of tibial bone defect. Sixty male Wistar rats were distributed into bone defect control group (CG) and Biosilicate® scaffold group (BG). Animals were euthanized 15, 30 and 45 days post-surgery. Stereomicroscopy, scanning electron microscopy, histopathological, immunohistochemistry and biomechanical analysis were used. Scaffolds had a total porosity of 44%, macroporosity of 15% with pore diameter of 230 μm. Higher amount of newly formed bone was observed on days 30 and 45 in BG. Immunohistochemistry analysis showed that the COX-2 expression was significantly higher on days 15 and 30…in BG compared with the CG. RUNX-2 immunoexpression was significantly higher in BG on days 15 and 45. No statistically significant difference was observed in RANKL immunoexpression in all experimental groups. BMP-9 immunoexpression was significantly upregulated in the BG on day 45. Biomechanical analysis showed a decrease in the biomechanical properties of the bone callus on days 30 and 45. The implantation of the Biosilicate® scaffolds was effective in stimulating newly bone formation and produced an increased immunoexpression of markers related to the bone repair.
Keywords: Biosilicate®, glass-ceramic, scaffold, bone repair, rats
Abstract: BACKGROUND: Electrospinning is a highly effective method in order to generate nano-scaled fibers. In conventional electrospinning technique, geometry of nanofibers are mostly random due to the chaotic behavior of polymer jet. OBJECTIVE: Purpose of this study is to produce aligned nanofibers from PVP polymers with advanced electrospinning technique in order to be used in a potential novel sensor applications, tissue regeneration and engineering. METHODS: In this study, by using finite hollow cylinder focusing electrodes, an external electrostatic field is created. With these electrodes, it is aimed to decrease whipping instability of polymer jet. In addition, it…is also investigated that the alignment ratio of nanofibers by using conductive parallel electrodes which placed through jet trajectory. RESULTS: In conclusion, with the effect of electrical field created by cylinder electrodes, radius of the fiber dispersion on the collector was able to be reduced and aligned nanofibers were successfully produced by using electrical field generated from the parallel plates. CONCLUSIONS: Radius of the fiber dispersion on the collector is 9.95 mm and fiber diameters varied between 800 nm and 3 μm. Additionally, alignment ratio of the fibers is determined with ImageJ software. These alignment of nanofibers can be used in tissue engineering applications and sensor applications.