Search results for: cochlear implant (CI)
100 Effects of Alkaline Pretreatment Parameters on the Corrosion Resistance and Wettability of Magnesium Implant
Authors: Mahtab Assadian, Mohd Hasbullah Idris, Mostafa Rezazadeh Shirdar, Mohammad Mahdi Taheri, S. Izman
Abstract:
Corrosion behaviour and surface roughness of magnesium substrate were investigated after NaOH pretreatment in different concentrations (1, 5, and 10 molar) and duration of (10 min, 30 min, 1 h, 3 h, 6 h and 24 h). Creation of Mg(OH)2 barrier layer after pretreatment enhanced corrostion resistance as well as wettability of substrate surface. Characterization including Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) was conducted to detect the existence of this barrier layer. Surface roughness and wettability of substrate was evaluated using atomic force microscopy (AFM) and contact angle measurement respectively. It is found that magnesium treated by 1M NaOH for 30 min reveals higher corrosion resistance and lower water contact angle of substrate surface. In addition, this investigation indicates that pH value of SBF solution is strongly influenced by different time and concentration of alkaline pretreatment.Keywords: magnesium, NaOH pretreatment, corrosion resistance, wettability
Procedia PDF Downloads 95699 A Virtual Electrode through Summation of Time Offset Pulses
Authors: Isaac Cassar, Trevor Davis, Yi-Kai Lo, Wentai Liu
Abstract:
Retinal prostheses have been successful in eliciting visual responses in implanted subjects. As these prostheses progress, one of their major limitations is the need for increased resolution. As an alternative to increasing the number of electrodes, virtual electrodes may be used to increase the effective resolution of current electrode arrays. This paper presents a virtual electrode technique based upon time-offsets between stimuli. Two adjacent electrodes are stimulated with identical pulses with too short of pulse widths to activate a neuron, but one has a time offset of one pulse width. A virtual electrode of twice the pulse width was then shown to appear in the center, with a total width capable of activating a neuron. This can be used in retinal implants by stimulating electrodes with pulse widths short enough to not elicit responses in neurons, but with their combined pulse width adequate to activate a neuron in between them.Keywords: electrical stimulation, neuroprosthesis, retinal implant, retinal prosthesis, virtual electrode
Procedia PDF Downloads 29698 Evaluation of the Efficacy of Titanium Alloy Dental Implants Coated by Bio-ceramic Apatite Wollastonite (Aw) and Hydroxyapatite (Ha) by Pulsed Laser Deposition
Authors: Betsy S. Thomas, Manjeet Marpara, K. M. Bhat
Abstract:
Introduction: After the initial enthusiasm and interest in hydroxyapatite products subsided due to dissolution of the coating and failure at the coating interface, this was a unique attempt to create a next generation of dental implant. Materials and Methods: The adhesion property of AW and HA coatings at various temperature by pulsed laser deposition was assessed on titanium plates. Moreover, AW/HA coated implants implanted in the femur of the rabbits was evaluated at various intervals. Results: Decohesion load was more for AW in scratch test and more bone formation around AW coated implants on histological evaluation. Discussion: AW coating by pulsed laser deposition was more adherent to the titanium surface and led to faster bone formation than HA. Conclusion: This experiment opined that AW coated by pulsed laser deposition seems to be a promising method in achieving bioactive coatings on titanium implants.Keywords: surface coating, dental implants, osseo integration, biotechnology
Procedia PDF Downloads 35997 The Role of Bone Marrow Stem Cells Transplantation in the Repair of Damaged Inner Ear in Albino Rats
Authors: Ahmed Gaber Abdel Raheem, Nashwa Ahmed Mohamed
Abstract:
Introduction: Sensorineural hearing loss (SNHL) is largely caused by the degeneration of the cochlea. Therapeutic options for SNHL are limited to hearing aids and cochlear implants. The cell transplantation approach to the regeneration of hair cells has gained considerable attention because stem cells are believed to accumulate in the damaged sites and have the potential for the repair of damaged tissues. The aim of the work: was to assess the use of bone marrow transplantation in repair of damaged inner ear hair cells in rats after the damage had been inflicted by Amikacin injection. Material and Methods: Thirty albino rats were used in this study. They were divided into three groups. Each group ten rats. Group I: used as control. Group II: Were given Amikacin- intratympanic injection till complete loss of hearing function. This could be assessed by Distortion product Otoacoustic Emission (DPOAEs) and / or auditory brain stem evoked potential (ABR). GroupIII: were given intra-peritoneal injection of bone marrow stem cell after complete loss of hearing caused by Amikacin. Clinical assessment was done using DPOAEs and / or auditory brain stem evoked potential (ABR), before and after bone marrow injection. Histological assessment of the inner ear was done by light and electron microscope. Also, Detection of stem cells in the inner ear by immunohistochemistry. Results: Histological examination of the specimens showed promising improvement in the structure of cochlea that may be responsible for the improvement of hearing function in rats detected by DPOAEs and / or ABR. Conclusion: Bone marrow stem cells transplantation might be useful for the treatment of SNHL.Keywords: amikacin, hair cells, sensorineural hearing loss, stem cells
Procedia PDF Downloads 44696 Static and Dynamic Load on Hip Contact of Hip Prosthesis and Thai Femoral Bones
Authors: K. Chalernpon, P. Aroonjarattham, K. Aroonjarattham
Abstract:
Total hip replacement had been one of the most successful operations in hip arthritis surgery. The purpose of this research had been to develop a dynamic hip contact of Thai femoral bone to analyze the stress distribution on the implant and the strain distribution on the bone model under daily activities and compared with the static load simulation. The results showed the different of maximum von Mises stress 0.14 percent under walking and 0.03 percent under climbing stair condition and the different of equivalent total strain 0.52 percent under walking and 0.05 percent under climbing stair condition. The muscular forces should be evaluated with dynamic condition to reduce the maximum von Mises stress and equivalent total strain.Keywords: dynamic loading, static load, hip prosthesis, Thai femur, femoral bone, finite element analysis
Procedia PDF Downloads 34495 Production and Characterization of Implant Material Produced by Using Electroless Ni Plated Al2O3-Co-Cr-Ti Powders
Authors: Ahmet Yonetken, Ayhan Erol
Abstract:
The microstructure, mechanical properties and corrosion characteristics of Ni plated %10Al2O3-%40Co-%20Cr and %10Ti powders were investigated using specimens produced by tube furnace sintering at 800-1200°C temperature. A uniform nickel layer on Al2O3-Co-Cr and Ti powders was deposited prior to sintering using electroless plating technique. A composite consisting of quintet additions, a metallic phase, Ti,Cr and Co including a ceramic phase, alumina, within a matrix of Ni has been prepared under Ar shroud and then tube furnace sintered. XRD, SEM (Scanning Electron Microscope), corrosion behavior in acidic media were investigated to characterize the properties of the specimens. Experimental results carried out for composition (%10Al2O3-%40Co-%20Cr- %10Ti)20Ni at 1200°C suggest that the best properties as 312.18HV were obtained at 1200°C.Keywords: sintering, intermetallic, Electroless nickel plating, composite
Procedia PDF Downloads 57094 Malposition of Femoral Component in Total Hip Arthroplasty
Authors: Renate Krassnig, Gloria M. Hohenberger, Uldis Berzins, Stefen Fischerauer
Abstract:
Background: Only a few reports discuss the effectiveness of intraoperative radiographs for placing femoral components. Therefore there is no international standard in using intraoperative imaging in the proceeding of total hip replacement. Method: Case report; an 84-year-old female patient underwent changing the components of the Total hip arthroplasty (THA) because of aseptic loosening. Due to circumstances, the surgeon decided to implant a cemented femoral component. The procedure was without any significant abnormalities. The first postoperative radiograph was planned after recovery – as usual. The x-ray imaging showed a misplaced femoral component. Therefore a CT-scan was performed additionally and the malposition of the cemented femoral component was confirmed. The patient had to undergo another surgery – removing of the cemented femoral component and implantation of a new well placed one. Conclusion: Intraoperative imaging of the femoral component is not a common standard but this case shows that intraoperative imaging is a useful method for detecting errors and gives the surgeon the opportunity to correct errors intraoperatively.Keywords: femoral component, intraoperative imaging, malplacement, revison
Procedia PDF Downloads 19393 Biological Evaluation of Some Modern Titanium Alloys for Dental Implants
Authors: Roxana Maria Angelescu, Raluca Ion, Anişoara Cîmpean, Doina Răducanu, Mariana Lucia Angelescu
Abstract:
In an attempt to find titanium alloys that fulfill the requirements for mechanical and biological compatibility, laboratory and material related tests were performed during the years, as well as preclinical and clinical trials. The multidisciplinary scientific research facilitates the global evaluation of biocompatibility and osseointegration regarding the dental implant alloys. The aim of this study was to determine the in vitro biocompatibility of three modern titanium alloys: Ti-31.7Nb-6.21Zr-1.4Fe-0.16O (wt%), Ti-36.5Nb-4.5Zr-3Ta-0.16O (wt%) and Ti-20Nb-5Ta (wt%), in order to establish whether the use of these titanium alloys can have any toxic or injurious effects on biological systems. The commonly used Ti-6Al-4V alloy was investigated as a reference material. The behavior of MC3T3-E1 pre-osteoblasts on all these four metallic surfaces was evaluated. The tests of immunofluorescence, cytotoxicity and cellular proliferation lead to the conclusion that the newly-developed titanium alloys elicit a good cellular response in terms of cellular survival, adhesion, morphology and proliferative potential as well.Keywords: biocompatibility tests, dental implants, titanium alloys, biomedical engineering
Procedia PDF Downloads 49692 Evaluation of Biological and Confinement Properties of a Bone Substitute to in Situ Preparation Based on Demineralized Bone Matrix for Bone Tissue Regeneration
Authors: Aura Maria Lopera Echavarria, Angela Maria Lema Perez, Daniela Medrano David, Pedronel Araque Marin, Marta Elena Londoño Lopez
Abstract:
Bone regeneration is the process by which the formation of new bone is stimulated. Bone fractures can originate at any time due to trauma, infections, tumors, congenital malformations or skeletal diseases. Currently there are different strategies to treat bone defects that in some cases, regeneration does not occur on its own. That is why they are treated with bone substitutes, which provide a necessary environment for the cells to synthesize new bone. The Demineralized Bone Matrix (DBM) is widely used as a bone implant due to its good properties, such as osteoinduction and bioactivity. However, the use of DBM is limited, because its presentation is powder, which is difficult to implant with precision and is susceptible to migrating to other sites through blood flow. That is why the DBM is commonly incorporated into a variety of vehicles or carriers. The objective of this project is to evaluate the bioactive and confinement properties of a bone substitute based on demineralized bone matrix (DBM). Also, structural and morphological properties were evaluated. Bone substitute was obtained from EIA Biomaterials Laboratory of EIA University and the DBM was facilitated by Tissue Bank Foundation. Morphological and structural properties were evaluated by scanning electron microscopy (SEM), X-ray diffraction (DRX) and Fourier transform infrared spectroscopy with total attenuated reflection (FTIR-ATR). Water absorption capacity and degradation were also evaluated during three months. The cytotoxicity was evaluated by the MTT test. The bioactivity of the bone substitute was evaluated through immersion of the samples in simulated body fluid during four weeks. Confinement tests were performed on tibial fragments of a human donor with bone defects of determined size, to ensure that the substitute remains in the defect despite the continuous flow of fluid. According of the knowledge of the authors, the methodology for evaluating samples in a confined environment has not been evaluated before in real human bones. The morphology of the samples showed irregular surface and presented some porosity. DRX confirmed a semi-crystalline structure. The FTIR-ATR determined the organic and inorganic phase of the sample. The degradation and absorption measurements stablished a loss of 3% and 150% in one month respectively. The MTT showed that the system is not cytotoxic. Apatite clusters formed from the first week were visualized by SEM and confirmed by EDS. These calcium phosphates are necessary to stimulate bone regeneration and thanks to the porosity of the developed material, osteinduction and osteoconduction are possible. The results of the in vitro evaluation of the confinement of the material showed that the migration of the bone filling to other sites is negligible, although the samples were subjected to the passage of simulated body fluid. The bone substitute, putty type, showed stability, is bioactive, non-cytotoxic and has handling properties for specialists at the time of implantation. The obtained system allows to maintain the osteoinductive properties of DBM and it can fill completely fractures in any way; however, it does not provide a structural support, that is, it should only be used to treat fractures without requiring a mechanical load.Keywords: bone regeneration, cytotoxicity, demineralized bone matrix, hydrogel
Procedia PDF Downloads 11391 Synthesis and Characterization of Akermanite Nanoparticles (AMN) as a Bio-Ceramic Nano Powder by Sol-Gel Method for Use in Biomedical
Authors: Seyedmahdi Mousavihashemi
Abstract:
Natural Akermanite (NAM) has been successfully prepared by a modified sol-gel method. Optimization in calcination temperature and mechanical ball milling resulted in a pure and nano-sized powder which characterized by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM) and Fourier transform infrared Spectroscopy (FT–IR). We hypothesized that nano-sized Akermanite (AM) would mimic more efficiently the nanocrystal structure and function of natural bone apatite, owing to the higher surface area, compare to conventional micron-size Akermanite (AM). Accordingly, we used the unique advantage of nanotechnology to improve novel nano akermanite particles as a potential candidate for bone tissue regeneration whether as a per implant filling powder or in combination with other biomaterials as a composite scaffold. Pure Akermanite (PAM) powders were successfully obtained via a simple sol-gel method followed by calcination at 1250 °C. Mechanical grinding in a ceramic ball mill for 7 hours resulted in akermanite (AM) nanoparticles in the range of about 30- 45 nm.Keywords: biomedical engineering, nano composite, SEM, TEM
Procedia PDF Downloads 23190 Mastopexy with the "Dermoglandular Autоaugmentation" Method. Increased Stability of the Result. Personalized Technique
Authors: Maksim Barsakov
Abstract:
Introduction. In modern plastic surgery, there are a large number of breast lift techniques.Due to the spreading information about the "side effects" of silicone implants, interest in implant-free mastopexy is increasing year after year. However, despite the variety of techniques, patients sometimes do not get full satisfaction from the results of mastopexy because of the unexpressed filling of the upper pole, extended anchoring postoperative scars and sometimes because of obtaining an aesthetically unattractive breast shape. The stability of the result after mastopexy depends on many factors, including postoperative rehabilitation. Stability of weight and hormonal background, stretchability of tissues. The high recurrence rate of ptosis and short-term aesthetic effect of mastopexy indicate the urgency of improving surgical techniques and increasing the stabilization of breast tissue. Purpose of the study. To develop and introduce into practice a technique of mastopexy based on the use of a modified Ribeiro flap, as well as elements of tissue movement and fixation designed to increase the stability of postoperative mastopexy. In addition, to give indications for the application of this surgical technique. Materials and Methods. it operated on 103 patients aged 18 to 53 years from 2019 to 2023 according to the reported method. These were patients with primary mastopexy, secondary mastopexy, and also patient with implant removal and one-stage mastopexy. The patients were followed up for 12 months to assess the stability of the result. Results and their discussion. Observing the patients, we noted greater stability of the breast shape and upper pole filling compared to the conventional classical methods. We did not have to resort to anchoring scars. In 90 percent of cases, a inverted T-shape scar was used. In 10 percent, the J-scar was used. The quantitative distribution of complications identified among the operated patients is as follows: worsened healing of the junction of vertical and horizontal sutures at the period of 1-1.5 months after surgery - 15 patients; at treatment with ointment method healing was observed in 7-30 days; permanent loss of NAC sensitivity - 0 patients; vascular disorders in the area of NAC/areola necrosis - 0 patients; marginal necrosis of the areola-2 patients. independent healing within 3-4 weeks without aesthetic defects. Aesthetically unacceptable mature scars-3 patients; partial liponecrosis of the autoflap unilaterally - 1 patient. recurrence of ptosis - 1 patient (after weight loss of 12 kg). In the late postoperative period, 2 patients became pregnant, gave birth, and no lactation problems were observed. Conclusion. Thus, in the world of plastic surgery methods of breast lift continue to improve, which is especially relevant in modern times, due to the increased attention to this operation. The author's proposed method of mastopexy with glandular autoflap allows obtaining in most cases a stable result, a fuller breast shape, avoiding the presence of extended anchoring scars, and also preserves the possibility of lactation. The author of this article has obtained a patent for invention for this method of mastopexy.Keywords: mastopexy, mammoplasty, autoflap, personal technique
Procedia PDF Downloads 2489 Influence of Ligature Tightening on Bone Fracture Risk in Interspinous Process Surgery
Authors: Dae Kyung Choi, Won Man Park, Kyungsoo Kim, Yoon Hyuk Kim
Abstract:
The interspinous process devices have been recently used due to its advantages such as minimal invasiveness and less subsidence of the implant to the osteoporotic bone. In this paper, we have analyzed the influences of ligature tightening of several interspinous process devices using finite element analysis. Four types of interspinous process implants were inserted to the L3-4 spinal motion segment based on their surgical protocols. Inferior plane of L4 vertebra was fixed and 7.5 Nm of extension moment were applied on superior plane of L3 vertebra with 400N of compressive load along follower load direction and pretension of the ligature. The stability of the spinal unit was high enough than that of intact model. The higher value of pretension in the ligature led the decrease of dynamic stabilization effect in cases of the WallisTM, DiamTM, Viking, and Spear®. The results of present study could be used to evaluate surgical option and validate the biomechanical characteristics of the spinal implants.Keywords: interspinous process device, bone fracture risk, lumbar spine, finite element analysis
Procedia PDF Downloads 39888 A Novel Photocrosslinkable and Cytocompatible Chitosan Coating for TI6AL4V Surfaces
Authors: D. Zujur, J. Moret, D. Rodriguez, L. Cruz, J. Lira, L. Gil, E. Dominguez, J. F. Alvarez-Barreto
Abstract:
In this work, chitosan (CH) has been used to produce a novel coating for Ti6Al4V, the most widely used alloy in orthopedic implants, so as to improve the biological tissue response at the metallic surface. The Ti6Al4V surface was sandblasted with alumina particles and observed by SEM. Chitosan was chemically modified, via crodiimide chemistry, with lactobionic and 4-azidebenzoic acid to make it soluble at physiological pH and photo-crosslinkable, respectively. The reaction was verified by FTIR, NMR, and UV/vis spectroscopy. Ti6Al4V surfaces were coated with solutions of the modified CH and exposed to UV light, causing the polymer crosslinking, and formation of a hydrogel on the surface. The crosslinking reaction was monitored by FTIR at different exposure times. Coating morphology was observed by SEM. The coating´s cytocompatibility was determined in vitro through the culture of rat bone marrow´s mesenchymal stem cells, using an MTT assay. The results show that the developed coating is cytocompatible, easy to apply and could be used for further studies in the encapsulation of bioactive molecules to improve osteogenic potential at the tissue-implant interface.Keywords: chitosan, photo-crosslinking, Ti6Al4V, bioactive coating, hydrogel
Procedia PDF Downloads 31587 The Implantable MEMS Blood Pressure Sensor Model With Wireless Powering And Data Transmission
Authors: Vitaliy Petrov, Natalia Shusharina, Vitaliy Kasymov, Maksim Patrushev, Evgeny Bogdanov
Abstract:
The leading worldwide death reasons are ischemic heart disease and other cardiovascular illnesses. Generally, the common symptom is high blood pressure. Long-time blood pressure control is very important for the prophylaxis, correct diagnosis and timely therapy. Non-invasive methods which are based on Korotkoff sounds are impossible to apply often and for a long time. Implantable devices can combine longtime monitoring with high accuracy of measurements. The main purpose of this work is to create a real-time monitoring system for decreasing the death rate from cardiovascular diseases. These days implantable electronic devices began to play an important role in medicine. Usually implantable devices consist of a transmitter, powering which could be wireless with a special made battery and measurement circuit. Common problems in making implantable devices are short lifetime of the battery, big size and biocompatibility. In these work, blood pressure measure will be the focus because it’s one of the main symptoms of cardiovascular diseases. Our device will consist of three parts: the implantable pressure sensor, external transmitter and automated workstation in a hospital. The Implantable part of pressure sensors could be based on piezoresistive or capacitive technologies. Both sensors have some advantages and some limitations. The Developed circuit is based on a small capacitive sensor which is made of the technology of microelectromechanical systems (MEMS). The Capacitive sensor can provide high sensitivity, low power consumption and minimum hysteresis compared to the piezoresistive sensor. For this device, it was selected the oscillator-based circuit where frequency depends from the capacitance of sensor hence from capacitance one can calculate pressure. The external device (transmitter) used for wireless charging and signal transmission. Some implant devices for these applications are passive, the external device sends radio wave signal on internal LC circuit device. The external device gets reflected the signal from the implant and from a change of frequency is possible to calculate changing of capacitance and then blood pressure. However, this method has some disadvantages, such as the patient position dependence and static using. Developed implantable device doesn’t have these disadvantages and sends blood pressure data to the external part in real-time. The external device continuously sends information about blood pressure to hospital cloud service for analysis by a physician. Doctor’s automated workstation at the hospital also acts as a dashboard, which displays actual medical data of patients (which require attention) and stores it in cloud service. Usually, critical heart conditions occur few hours before heart attack but the device is able to send an alarm signal to the hospital for an early action of medical service. The system was tested with wireless charging and data transmission. These results can be used for ASIC design for MEMS pressure sensor.Keywords: MEMS sensor, RF power, wireless data, oscillator-based circuit
Procedia PDF Downloads 58286 Electrochemical Corrosion Behavior of New Developed Titanium Alloys in Ringer’s Solution
Authors: Yasser M. Abd-elrhman, Mohamed A. Gepreel, Kiochi Nakamura, Ahmed Abd El-Moneim, Sengo Kobayashi, Mervat M. Ibrahim
Abstract:
Titanium alloys are known as highly bio compatible metallic materials due to their high strength, low elastic modulus, and high corrosion resistance in biological media. Besides other important material features, the corrosion parameters and corrosion products are responsible for limiting the biological and chemical bio compatibility of metallic materials that produce undesirable reactions in implant-adjacent and/or more distant tissues. Electrochemical corrosion behaviors of novel beta titanium alloys, Ti-4.7Mo-4.5Fe, Ti-3Mo-0.5Fe, and Ti-2Mo-0.5Fe were characterized in naturally aerated Ringer’s solution at room temperature compared with common used biomedical titanium alloy, Ti-6Al-4V. The corrosion resistance of titanium alloys were investigated through open circuit potential (OCP), potentiodynamic polarization measurements and optical microscope (OM). A high corrosion resistance was obtained for all alloys due to the stable passive film formed on their surfaces. The new present alloys are promising metallic biomaterials for the future, owing to their very low elastic modulus and good corrosion resistance capabilities.Keywords: titanium alloys, corrosion resistance, Ringer’s solution, electrochemical corrosion
Procedia PDF Downloads 64685 A Hardware-in-the-loop Simulation for the Development of Advanced Control System Design for a Spinal Joint Wear Simulator
Authors: Kaushikk Iyer, Richard M Hall, David Keeling
Abstract:
Hardware-in-the-loop (HIL) simulation is an advanced technique for developing and testing complex real-time control systems. This paper presents the benefits of HIL simulation and how it can be implemented and used effectively to develop, test, and validate advanced control algorithms used in a spinal joint Wear simulator for the Tribological testing of spinal disc prostheses. spinal wear simulator is technologically the most advanced machine currently employed For the in-vitro testing of newly developed spinal Discimplants. However, the existing control techniques, such as a simple position control Does not allow the simulator to test non-sinusoidal waveforms. Thus, there is a need for better and advanced control methods that can be developed and tested Rigorouslybut safely before deploying it into the real simulator. A benchtop HILsetupis was created for experimentation, controller verification, and validation purposes, allowing different control strategies to be tested rapidly in a safe environment. The HIL simulation aspect in this setup attempts to replicate similar spinal motion and loading conditions. The spinal joint wear simulator containsa four-Barlinkpowered by electromechanical actuators. LabVIEW software is used to design a kinematic model of the spinal wear Simulator to Validatehow each link contributes towards the final motion of the implant under test. As a result, the implant articulates with an angular motion specified in the international standards, ISO-18192-1, that define fixed, simplified, and sinusoid motion and load profiles for wear testing of cervical disc implants. Using a PID controller, a velocity-based position control algorithm was developed to interface with the benchtop setup that performs HIL simulation. In addition to PID, a fuzzy logic controller (FLC) was also developed that acts as a supervisory controller. FLC provides intelligence to the PID controller by By automatically tuning the controller for profiles that vary in amplitude, shape, and frequency. This combination of the fuzzy-PID controller is novel to the wear testing application for spinal simulators and demonstrated superior performance against PIDwhen tested for a spectrum of frequency. Kaushikk Iyer is a Ph.D. Student at the University of Leeds and an employee at Key Engineering Solutions, Leeds, United Kingdom, (e-mail: [email protected], phone: +44 740 541 5502). Richard M Hall is with the University of Leeds, the United Kingdom as a professor in the Mechanical Engineering Department (e-mail: [email protected]). David Keeling is the managing director of Key Engineering Solutions, Leeds, United Kingdom (e-mail: [email protected]). Results obtained are successfully validated against the load and motion tolerances specified by the ISO18192-1 standard and fall within limits, that is, ±0.5° at the maxima and minima of the motion and ±2 % of the complete cycle for phasing. The simulation results prove the efficacy of the test setup using HIL simulation to verify and validate the accuracy and robustness of the prospective controller before its deployment into the spinal wear simulator. This method of testing controllers enables a wide range of possibilities to test advanced control algorithms that can potentially test even profiles of patients performing various dailyliving activities.Keywords: Fuzzy-PID controller, hardware-in-the-loop (HIL), real-time simulation, spinal wear simulator
Procedia PDF Downloads 16484 A Textile-Based Scaffold for Skin Replacements
Authors: Tim Bolle, Franziska Kreimendahl, Thomas Gries, Stefan Jockenhoevel
Abstract:
The therapeutic treatment of extensive, deep wounds is limited. Autologous split-skin grafts are used as a so-called ‘gold standard’. Most common deficits are the defects at the donor site, the risk of scarring as well as the limited availability and quality of the autologous grafts. The aim of this project is a tissue engineered dermal-epidermal skin replacement to overcome the limitations of the gold standard. A key requirement for the development of such a three-dimensional implant is the formation of a functional capillary-like network inside the implant to ensure a sufficient nutrient and gas supply. Tailored three-dimensional warp knitted spacer fabrics are used to reinforce the mechanically week fibrin gel-based scaffold and further to create a directed in vitro pre-vascularization along the parallel-oriented pile yarns within a co-culture. In this study various three-dimensional warp knitted spacer fabrics were developed in a factorial design to analyze the influence of the machine parameters such as the stitch density and the pattern of the fabric on the scaffold performance and further to determine suitable parameters for a successful fibrin gel-incorporation and a physiological performance of the scaffold. The fabrics were manufactured on a Karl Mayer double-bar raschel machine DR 16 EEC/EAC. A fine machine gauge of E30 was used to ensure a high pile yarn density for sufficient nutrient, gas and waste exchange. In order to ensure a high mechanical stability of the graft, the fabrics were made of biocompatible PVDF yarns. Key parameters such as the pore size, porosity and stress/strain behavior were investigated under standardized, controlled climate conditions. The influence of the input parameters on the mechanical and morphological properties as well as the ability of fibrin gel incorporation into the spacer fabric was analyzed. Subsequently, the pile yarns of the spacer fabrics were colonized with Human Umbilical Vein Endothelial Cells (HUVEC) to analyze the ability of the fabric to further function as a guiding structure for a directed vascularization. The cells were stained with DAPI and investigated using fluorescence microscopy. The analysis revealed that the stitch density and the binding pattern have a strong influence on both the mechanical and morphological properties of the fabric. As expected, the incorporation of the fibrin gel was significantly improved with higher pore sizes and porosities, whereas the mechanical strength decreases. Furthermore, the colonization trials revealed a high cell distribution and density on the pile yarns of the spacer fabrics. For a tailored reinforcing structure, the minimum porosity and pore size needs to be evaluated which still ensures a complete incorporation of the reinforcing structure into the fibrin gel matrix. That will enable a mechanically stable dermal graft with a dense vascular network for a sufficient nutrient and oxygen supply of the cells. The results are promising for subsequent research in the field of reinforcing mechanically weak biological scaffolds and develop functional three-dimensional scaffolds with an oriented pre-vascularization.Keywords: fibrin-gel, skin replacement, spacer fabric, pre-vascularization
Procedia PDF Downloads 25083 Piezosurgery in Periodontics and Oral Implantology
Authors: Neelesh Papineni
Abstract:
Aim: Piezosurgery is a relatively new technique for osteotomy and osteoplasty that uses ultrasonic vibration. The conventional method of treating periodontal cases are by conventional surgeries. However, in this advancing field the use of motor-driven instruments is being considered less invasive. Out of these motor-driven instruments, piezo-electric device has been introduced to the field of periodontics and oral implantology. This article discusses about the wide range of application of piezo-electric device in periodontology, its advantages over conventional surgical therapies and other motor-driven instruments. Results: Piezo- electric has shown better results in aspect of osteotomy, osteoplasty, implants, and any procedure which includes conserving the bone. Also piezo-electric does not cause any kind of damage to the surrounding soft tissue and eliminates the risk of bone necrosis which is a risk factor in other motor driven instruments. Conclusion: In this era of modern dentistry , a successful periodontal and implant surgery requires a sound osseous support. This review gives a pictorial representation about the wide range of application of piezo-electric device in periodontology.Keywords: piezo-electric, osteotomy, osteoplasty, implantology
Procedia PDF Downloads 37082 Comparison of the Effects of Rod Types of Rigid Fixation Devices on the Loads in the Lumbar Spine: A Finite Element Analysis
Authors: Bokku Kang, Changsoo Chon, Han Sung Kim
Abstract:
We developed new design of rod of pedicle screw system that is beneficial in maintaining the spacing between the vertebrae and assessed the performance of the posterior fixation screw systems by numerical analysis according to the range of motion (flexion, extension, lateral bending, and axial rotation) of the vertebral column after inserting the pedicle screws. The simulation results showed that the conventional rod was the most low equivalent stress value among implant units in the case of flexion, extension and lateral bending of the vertebrae. In all cases except the torsional rotation, the results showed that the stress level of the single and double rounded rod exceeded about 30% to 70% compare to the conventional rod. Therefore, this product is not suitable for actual application in the field yet and it seems that product design optimization is necessary. Acknowledgement: This research was supported by the Ministry of Trade, Industry & Energy (MOTIE), Korea Institute for Advancement of Technology (KIAT) through the Encouragement Program for The Industries of Economic Cooperation Region.Keywords: lumber spine, internal fixation device, finite element method, biomechanics
Procedia PDF Downloads 37381 Differential Survival Rates of Pseudomonas aeruginosa Strains on the Wings of Pantala flavescens
Authors: Banu Pradheepa Kamarajan, Muthusamy Ananthasubramanian
Abstract:
Biofilm forming Pseudomonads occupy the top third position in causing hospital acquired infections. P. aeruginosa is notoriously known for its tendency to develop drug resistance. Major classes of drug such as β-lactams, aminoglycosides, quinolones, and polymyxins are found ineffective against multi-drug resistance Pseudomonas. To combat the infections, rather than administration of a single antibiotic, use of combinations (tobramycin and essential oils from plants and/or silver nanoparticles, chitosan, nitric oxide, cis-2-decenoic acid) in single formulation are suggested to control P. aeruginosa biofilms. Conventional techniques to prevent hospital-acquired implant infections such as coatings with antibiotics, controlled release of antibiotics from the implant material, contact-killing surfaces, coating the implants with functional DNase I and, coating with glycoside hydrolase are being followed. Coatings with bioactive components besides having limited shelf-life, require cold-chain and, are likely to fail when bacteria develop resistance. Recently identified nano-scale physical architectures on the insect wings are expected to have potential bactericidal property. Nanopillars are bactericidal to Staphylococcus aureus, Bacillus subtilis, K. pnuemoniae and few species of Pseudomonas. Our study aims to investigate the survival rate of biofilm forming Pseudomonas aeruginosa strain over non-biofilm forming strain on the nanopillar architecture of dragonfly (Pantala flavescens) wing. Dragonflies were collected near house-hold areas and, insect identification was carried out by the Department of Entomology, Tamilnadu Agricultural University, Coimbatore, India. Two strains of P. aeruginosa such as PAO1 (potent biofilm former) and MTCC 1688 (non-weak biofilm former) were tested against the glass coverslip (control) and wings of dragonfly (test) for 48 h. The wings/glass coverslips were incubated with bacterial suspension in 48-well plate. The plates were incubated at 37 °C under static condition. Bacterial attachment on the nanopillar architecture of the wing surface was visualized using FESEM. The survival rate of P. aeruginosa was tested using colony counting technique and flow cytometry at 0.5 h, 1 h, 2 h, 7 h, 24 h, and 48 h post-incubation. Cell death was analyzed using propidium iodide staining and DNA quantification. The results indicated that the survival rate of non-biofilm forming P. aeruginosa is 0.2 %, whilst that of biofilm former is 45 % on the dragonfly wings at the end of 48 h. The reduction in the survival rate of biofilm and non-biofilm forming P. aeruginosa was 20% and 40% respectively on the wings compared to the glass coverslip. In addition, Fourier Transformed Infrared Radiation was used to study the modification in the surface chemical composition of the wing during bacterial attachment and, post-sonication. This result indicated that the chemical moieties are not involved in the bactericidal property of nanopillars by the conserved characteristic peaks of chitin pre and post-sonication. The nanopillar architecture of the dragonfly wing efficiently deters the survival of non-biofilm forming P. aeruginosa, but not the biofilm forming strain. The study highlights the ability of biofilm formers to survive on wing architecture. Understanding this survival strategy will help in designing the architecture that combats the colonization of biofilm forming pathogens.Keywords: biofilm, nanopillars, Pseudomonas aeruginosa, survival rate
Procedia PDF Downloads 17080 Wireless Capsule Endoscope - Antenna and Channel Characterization
Authors: Mona Elhelbawy, Mac Gray
Abstract:
Traditional wired endoscopy is an intrusive process that requires a long flexible tube to be inserted through the patient’s mouth while intravenously sedated. Only images of the upper 4 feet of stomach, colon, and rectum can be captured, leaving the remaining 20 feet of small intestines. Wireless capsule endoscopy offers a painless, non-intrusive, efficient and effective alternative to traditional endoscopy. In wireless capsule endoscopy (WCE), ingestible vitamin-pill-shaped capsules with imaging capabilities, sensors, batteries, and antennas are designed to send images of the gastrointestinal (GI) tract in real time. In this paper, we investigate the radiation performance and specific absorption rate (SAR) of a miniature conformal capsule antenna operating at the Medical Implant Communication Service (MICS) frequency band in the human body. We perform numerical simulations using the finite element method based commercial software, high-frequency structure simulator (HFSS) and the ANSYS human body model (HBM). We also investigate the in-body channel characteristics between the implantable capsule and an external antenna placed on the surface of the human body.Keywords: IEEE 802.15.6, MICS, SAR, WCE
Procedia PDF Downloads 12579 Influence of Ball Milling Time on Mechanical Properties of Porous Ti-20Nb-5Ag Alloy
Authors: M. J. Shivaram, Shashi Bhushan Arya, Jagannath Nayak, Bharat Bhooshan Panigrahi
Abstract:
Titanium and its alloys have become more significant implant materials due to their mechanical properties, excellent biocompatibility and high corrosion resistance. Biomaterials can be produce by using the powder metallurgy (PM) methods and required properties can tailored by varying the processing parameters, such as ball milling time, space holder particles, and sintering temperature. The desired properties such as, structural and mechanical properties can be obtained by powder metallurgy method. In the present study, deals with fabrication of solid and porous Ti-20Nb-5Ag alloy using high energy ball milling for different times (5 and 20 h). The resultant powder particles were used to fabricate solid and porous Ti-20Nb-5Ag alloy by adding space holder particles (NH4HCO3). The resultant powder particles, fabricated solid and porous samples were characterized by scanning electron microscopy (SEM). The compressive strength, elastic modulus and microhardness properties were investigated. Solid and porous Ti-20Nb-5Ag alloy samples showed good mechanical properties for 20 h ball milling time as compare to 5 h ball milling.Keywords: ball milling, compressive strengths, microstructure, porous titanium alloy
Procedia PDF Downloads 29378 Multidisciplinary Rehabilitation Algorithm after Mandibular Resection for Ameloblastoma
Authors: Joaquim de Almeida Dultra, Daiana Cristina Pereira Santana, Fátima Karoline Alves Araújo Dultra, Liliane Akemi Kawano Shibasaki, Mariana Machado Mendes de Carvalho, Ieda Margarida Crusoé Rocha Rebello
Abstract:
Defects originating from mandibular resections can cause significant functional impairment and facial disharmony, and they have complex rehabilitation. The aim of this report is to demonstrate the authors' experience facing challenging rehabilitation after mandibular resection in a patient with ameloblastoma. Clinical and surgical steps are described simultaneously, highlighting the adaptation of the final fixed prosthesis, reported in an unprecedented way in the literature. A 37-year-old male patient was seen after a sports accident, where a pathological fracture in the symphysis and left mandibular body was identified, where a large radiolucent lesion was found. The patient underwent resection, bone graft, distraction osteogenesis, rehabilitation with dental implants, prosthesis, and finally, orofacial harmonization, in an interval of six years. Rehabilitation should consider the patient's needs individually and should have as the main objective to provide similar aesthetics and function to that present before the disease. We also emphasize the importance of interdisciplinary work during the course of rehabilitation.Keywords: ameloblastoma, mandibular reconstruction, distraction osteogenesis, dental implants. dental prosthesis, implant-supported, treatment outcome
Procedia PDF Downloads 10377 Comparing Implications of Manual and ROSA-assisted Total Knee Replacements on Patients and Physicians: A Scoping Review
Authors: Bassem M. Darwish, Robert H. Ablove
Abstract:
Introduction: Total knee arthroscopy (TKA) is a commonly performed procedure in patients with end-stage osteoarthritis and inaccuracy of component alignment in TKA has been shown to have many adverse post-operative outcomes such as accelerated implant wear, reduced functional outcomes, and shorter overall implant survival. Robotic surgical systems have been introduced to try and improve joint alignment and functional outcomes in knee arthroscopy, one recent iteration is the ROSA knee system, released to the market in 2019. The objective of this scoping review is to map the available evidence, identify the current types of evidence, and identify knowledge gaps to guide future studies on patient outcomes following ROSA-assisted total knee arthroplasties. Methods: An electronic search was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) extension for scoping reviews. Search terms included ROSA, knee arthroscopy, osteoarthritis, robotic, and malalignment. Types of study participants included patients with osteoarthritis, ages 18 and older, male or female, who received manual TKA (mTKA) or ROSA-assisted TKA (rTKA), and human patients or cadavers. Published, peer-reviewed controlled trials, observational studies, and case series were included. Case reports were not included in article review. Resulting articles were first screened based on title and abstract. Articles meeting inclusion criteria based on title and abstract review then underwent full-text review by the same reviewer. Results: This scoping review identified 11 total studies, 3 prospective observational studies, and 8 retrospective observational studies - a total of 970 rTKA patients and 1745 mTKA patients. There were no case series or randomized controlled trials comparing rTKA and mTKA. Patient-centered outcomes showed promise for rTKA, where it frequently showed significantly favorable functional outcomes, measured via KOOS-JR, VAS, KSS, OKS, FJS, and PROMIS scores, at various times postoperatively. However, there was much discrepancy about which score yielded significance at which postoperative follow-up. Complication rates, reoperation rates, and LOS were very similar between mTKA and rTKA groups. Studies also showed rTKA had more accurate joint alignment within the 0 ± 3o corridor and had significantly higher rates of achieving postoperative joint angles similar to the preoperative plan. Finally, there was major agreement that rTKA cases take significantly longer time at the start, however, there is a rapid learning curve. Once past the learning curve, rTKA cases are performed in a similar time to mTKA and reduced physician stress and strain. Conclusion: The ROSA knee system represents a promising option for the management of osteoarthritis via total knee arthroscopy. The studies reviewed in this paper favor the patient-centered function outcomes, joint alignments, and physician health implications of the ROSA knee system to conventional total knee arthroscopy. Further study is warranted, however, to better understand recovery periods, longer-term functional outcomes, operative fatigue, and reduction in radiation exposure.Keywords: arthroplasty, knee, robotics, malalignment
Procedia PDF Downloads 1276 UV Enhanced Hydrophilicity of the Anodized Films Formed at Low Current Density and Low Voltage
Authors: Phanawan Whangdee, Tomoaki Watanabe, Viritpon Srimaneepong, Dujreutai Pongkao Kashima
Abstract:
The anodized films formed at high current density or high voltage have been widely prepared for dental implant because it can improve the hydrophilicity to the film. Our attempt is exploring whether low current density and low voltage could enhance the good hydrophilicity to the anodized films or not. Furthermore, UV irradiation would be one of the key factor to enhance their hydrophilicity. The anodized films were performed at low current density of 2 mA/cm2 in 1M H3PO4, 1 mA/cm2 in 1M MCPM and low voltage of 6 V in either 1M H3PO4 or 1M MCPM. All samples were treated with UV for various times up to 24 h. After UV irradiation, the contact angle decreased, the chemical species changed. The Ti 2p and O 1s peaks increased, while the C 1s peak decreased which might be due to removal of hydrocarbon. The functional groups of the films shown as the change of OH groups appeared at wave number 3700 cm-1 and 2900-3000 cm-1, however, the peak of H2O at 1630 cm-1disappeared. It is indicated that UV irradiation might change the stretching modes of OH groups coordinated to surface Ti4+ cation but UV did not affect to the changes in surface morphologies. The surface energies increased after UV irradiation resulting in improving of the hydrophilicity. The anodized films formed at low current density or low voltage after UV irradiation showed a low contact angle as well as the film formed at high current density or high voltage.Keywords: hydrophilicity, low current density, low voltage, UV irradiation
Procedia PDF Downloads 49475 External Retinal Prosthesis Image Processing System Used One-Cue Saliency Map Based on DSP
Authors: Yili Chen, Jixiang Fu, Zhihua Liu, Zhicheng Zhang, Rongmao Li, Nan Fu, Yaoqin Xie
Abstract:
Retinal prothesis is designed to help the blind to get some sight.It is made up of internal part and external part.In external part ,there is made up of camera, image processing, and RF transmitter.In internal part, there is RF receiver, implant chip,micro-electrode.The image got from the camera should be processed by suitable stragies to corresponds to stimulus the electrode.Nowadays, the number of the micro-electrode is hundreds and we don’t know the mechanism how the elctrode stimulus the optic nerve, an easy way to the hypothesis is that the pixel in the image is correspondence to the electrode.So it is a question how to get the important information of the image captured from the picture.There are many strategies to experimented to get the most important information as soon as possible, due to the real time system.ROI is a useful algorithem to extract the region of the interest.Our paper will explain the details of the orinciples and functions of the ROI.And based on this, we simplified the ROI algrithem,and used it in outside image prcessing DSP system of the retinal prothesis.Results show that our image processing stratiges is suitable for real-time retinal prothesis and can cut redundant information and help useful information to express in the low-size image.Keywords: image processing, region of interest, saliency map, low-size image, useful information express, cut redundant information in image
Procedia PDF Downloads 27574 TiO2 Formation after Nanotubes Growth on Ti-15Mo Alloy Surface for Different Annealing Temperatures
Authors: A. L. R. Rangel, J. A. M. Chaves, A. P. R. Alves Claro
Abstract:
Surface modification of titanium and its alloys using TiO2 nanotube growth has been widely studied for biomedical field due to excellent interaction between implant and biological environment. The success of this treatment is directly related to anatase phase formation (TiO2 phase) which affects the cells growth. The aim of this study was to evaluate the phases formed in the nanotubes growth on the Ti-15Mo surface. Nanotubes were grown by electrochemical anodization of the alloy in ammonium fluoride based glycerol electrolyte for 24 hours at 20V. Then, the samples were annealed at 200°,400°, 450°, 500°, 600°, and 800° C for 1 hour. Contact angles measurements, scanning electron microscopy images and X rays diffraction analysis (XRD) were carried out for all samples. Raman Spectroscopy was used to evaluate TiO2 phases transformation in nanotubes samples as well. The results of XRD showed anatase formation for lower temperatures, while at 800 ° C the rutile phase was observed all over the surface. Raman spectra indicate that this phase transition occurs between 500 and 600 °C. The different phases formed have influenced the nanotubes morphologies, since higher annealing temperatures induced agglutination of the TiO2 layer, disrupting the tubular structure. On the other hand, the nanotubes drastically reduced the contact angle, regardless the annealing temperature.Keywords: nanotubes, TiO2, titanium alloys, Ti-15Mo
Procedia PDF Downloads 37973 Tool Wear Analysis in 3D Manufactured Ti6AI4V
Authors: David Downey
Abstract:
With the introduction of additive manufacturing (3D printing) to produce titanium (Ti6Al4V) components in the medical/aerospace and automotive industries, intricate geometries can be produced with virtually complete design freedom. However, the consideration of microstructural anisotropy resulting from the additive manufacturing process becomes necessary due to this design flexibility and the need to print a geometric shape that can consist of numerous angles, radii, and swept surfaces. A femoral knee implant serves as an example of a 3D-printed near-net-shaped product. The mechanical properties of the printed components, and consequently, their machinability, are affected by microstructural anisotropy. Currently, finish-machining operations performed on titanium printed parts using selective laser melting (SLM) utilize the same cutting tools employed for processing wrought titanium components. Cutting forces for components manufactured through SLM can be up to 70% higher than those for their wrought counterparts made of Ti6Al4V. Moreover, temperatures at the cutting interface of 3D printed material can surpass those of wrought titanium, leading to significant tool wear. Although the criteria for tool wear may be similar for both 3D printed and wrought materials, the rate of wear during the machining process may differ. The impact of these issues on the choice of cutting tool material and tool lifetimes will be discussed.Keywords: additive manufacturing, build orientation, microstructural anisotropy, printed titanium Ti6Al4V, tool wear
Procedia PDF Downloads 8572 Microstructural and Corrosion Analysis of a Ti-Nb-Ta Biocompatible Dental Implant Alloy
Authors: Roxana Maria Angelescu, Doina Răducanu, Mariana Lucia Angelescu, Ion Cincă, Vasile Dănuţ Cojocaru, Cosmin Cotruț, Şerban Nicolae
Abstract:
Titanium alloys are often used for biomedical applications as hard tissue replacements, such as: orthopedic implants, spinal fixation devices and dental implants. Their advantages are well known and demonstrated: excellent mechanical properties, biocompatibility and good corrosion resistance, but it is also known that the main disadvantage of the metallic materials is their tendency of corrosion in in-vivo environments. In 1987, titanium was found to be the only metallic biomaterial that osseointegrates. The aim of this study was to investigate the microstructure and the corrosion behavior of the Ti-20Nb-5Ta wt% alloy. In this case Nb stabilizes the β-Ti structure and Ta is a highly passivating metal. The as studied alloy was melt under argon protective atmosphere in a levitation induction melting furnace, type FIVE CELES - MP25, with a nominal power of 25 kW and a melting capacity of 30 cm3. The microstructure of the as studied alloy was analyzed by using the electronic microscope Tescan Vega II-XMU. The phase structure of the as studied alloy was determined, as well as the crystalline grain size (100-200µ). To determine the corrosion behavior of the as studied alloy, the technique used was the linear polarization, with the PARSTAT 4000 potentiostat, produced by Princeton Applied Research; potentiodynamic curves were obtained with the VeraStudio v.2.4.2 software.Keywords: corrosion resistance, microstructure, titanium alloys
Procedia PDF Downloads 53471 Social Collaborative Learning Model Based on Proactive Involvement to Promote the Global Merit Principle in Cultivating Youths' Morality
Authors: Wera Supa, Panita Wannapiroon
Abstract:
This paper is a report on the designing of the social collaborative learning model based on proactive involvement to Promote the global merit principle in cultivating youths’ morality. The research procedures into two phases, the first phase is to design the social collaborative learning model based on proactive involvement to promote the global merit principle in cultivating youths’ morality, and the second is to evaluate the social collaborative learning model based on proactive involvement. The sample group in this study consists of 15 experts who are dominant in proactive participation, moral merit principle and youths’ morality cultivation from executive level, lecturers and the professionals in information and communication technology expertise selected using the purposive sampling method. Data analyzed by arithmetic mean and standard deviation. This study has explored that there are four significant factors in promoting the hands-on collaboration of global merit scheme in order to implant virtues to adolescences which are: 1) information and communication Technology Usage; 2) proactive involvement; 3) morality cultivation policy, and 4) global merit principle. The experts agree that the social collaborative learning model based on proactive involvement is highly appropriate.Keywords: social collaborative learning, proactive involvement, global merit principle, morality
Procedia PDF Downloads 379