Abstract: COMTES FHT has been active in a field of research and development of high-strength wires for quite some time. The main material was pure titanium. The primary goal of this effort is to develop a continuous production process for ultrafine and nanostructured materials with the aid of severe plastic deformation (SPD). This article outlines mechanical and microstructural properties of the materials and the options available for testing the components made of these materials. Ti Grade 2 and Grade 4 wires are the key products of interest. Ti Grade 2 with ultrafine to nano-sized grain shows ultimate strength of up to 1050 MPa. Ti Grade 4 reaches ultimate strengths of up to 1250 MPa. These values are twice or three times as higher as those found in the unprocessed material. For those fields of medicine where implantable metallic materials are used, bulk ultrafine to nanostructured titanium is available. It is manufactured by SPD techniques. These processes leave the chemical properties of the initial material unchanged but markedly improve its final mechanical properties, in particular, the strength. Ultrafine to nanostructured titanium retains all the significant and, from the biological viewpoint, desirable properties that are important for its use in medicine, i.e. those properties which made pure titanium the preferred material also for dental implants.
Abstract: We investigated magneto-optical Kerr effect in transparent region of implanted ferrite-garnet films for the (YBiCa)3(FeGe)5O12. The implantation process was carried out at room temperature by Ne+ ions with energy of 100 KeV and with various doses (0.5-2.5) 1014 ion/cm2. We discovered that slight deviation of the plane of external alternating magnetic field from plane of sample leads to appearance intensive magneto-optical maximum in transparent region of garnet films ħω=0.5-2.0 eV. In the proceeding, we have also found that the deviation of polarization plane from P- component of incident light leads to the appearance of the similar magneto-optical effects in this region. The research of magnetization processes in transparent region of garnet films showed that the formation of magneto-optical effects in region ħω=0.5-2.3 eV has a rather complex character.
Abstract: Previously, some materials like solid metals and their alloys have been used as implants in human’s body. In order to amend fixation of these artificial hard human tissues, some porous structures have been introduced. In this way, tissues in vicinity of the porous structure can be attached more easily to the inserted implant. In particular, the porous bone scaffolds are useful since they can deliver important biomolecules like growth factors and proteins. This study focuses on the properties of the degradable porous hard tissues using a three-dimensional numerical Finite Element Method (FEM). The most important studied properties of these structures are diffusivity flux and concentration of different species like glucose, oxygen, and lactate. The process of cells migration into the scaffold is considered as a diffusion process, and related parameters are studied for different values of production/consumption rates.
Abstract: Nitrogen implantation in aluminum and its alloys is acquainted for the difficulties in obtaining modified layers deeper than 200 nm. The present work addresses a new method to overcome such a problem; although, the coating with nitrogen and oxygen obtained by plasma immersion ion implantation (PIII) into a 7075 aluminum alloy surface was too shallow. This alloy is commonly used for structural parts in aerospace applications. Such a layer was characterized by secondary ion mass spectroscopy, electron microscopy, and nanoindentation experiments reciprocating wear tests. From the results, one can assume that the wear of this aluminum alloy starts presenting severe abrasive wear followed by an additional adhesive mechanism. PIII produced a slight difference, as shown in all characterizations carried out in this work. The results shown here can be used as the scientific basis for further nitrogen PIII experiments in aluminum alloys which have the goal to produce thicker modified layers or to improve their surface properties.
Abstract: In this work, the hemodynamics in the sinuses of
Valsalva after Transcatheter Aortic Valve Implantation is numerically
examined. We focus on the physical results in the two-dimensional
case. We use a finite element methodology based on a Lagrange
multiplier technique that enables to couple the dynamics of blood
flow and the leaflets’ movement. A massively parallel implementation
of a monolithic and fully implicit solver allows more accuracy and
significant computational savings. The elastic properties of the aortic
valve are disregarded, and the numerical computations are performed
under physiologically correct pressure loads. Computational results
depict that blood flow may be subject to stagnation in the lower
domain of the sinuses of Valsalva after Transcatheter Aortic Valve
Implantation.
Abstract: Renewable energy recovery is an important domain of research in past few years in view of protection of our ecosystem. Several industrial companies are setting up widespread recovery systems to exploit wave energy. Most of them have a large size, are implanted near the shores and exploit current flows. However, as oceans represent 70% of Earth surface, a huge space is still unexploited to produce energy. Present analysis focuses on surface small scale wave energy recovery. The principle is exactly the opposite of wheel damper for a car on a road. Instead of maintaining the car body as non-oscillatory as possible by adapted control, a system is designed so that its oscillation amplitude under wave action will be maximized with respect to a boat carrying it in view of differential potential energy recuperation. From parametric analysis of system equations, interesting domains have been selected and expected energy output has been evaluated.
Abstract: An ion implantation technique was used for designing the surface area of a titanium alloy and for irradiation-enhanced hardening of the surface. The Ti6Al4V alloy was treated by nitrogen ion implantation at fluences of 2·1017 and 4·1017 cm-2 and at ion energy 90 keV. The depth distribution of the nitrogen was investigated by Rutherford Backscattering Spectroscopy. The gradient of mechanical properties was investigated by nanoindentation. The continuous measurement mode was used to obtain depth profiles of the indentation hardness and the reduced storage modulus of the modified surface area. The reduced storage modulus and the hardness increase with increasing fluence. Increased fluence shifts the peak of the mechanical properties as well as the peak of nitrogen concentration towards to the surface. This effect suggests a direct relationship between mechanical properties and nitrogen distribution.
Abstract: There are many types of mechanical failure on the
dental implant. In this project, the failure that needs to take into
consideration is the bone resorption on the dental implant. Human
bone has its ability to remodel after the implantation. As the dental
implant is installed into the bone, the bone will detect and change the
bone structure to achieve new biomechanical environment. This
phenomenon is known as bone remodeling. The objective of the
project is to improve the performance of dental implant by using
different types of design. These designs are used to analyze and
predict the failure of the dental implant by using finite element
analysis (FEA) namely ANSYS. The bone is assumed to be fully
attached to the implant or cement. Hence, results are then compared
with other researchers. The results were presented in the form of Von
Mises stress, normal stress, shear stress analysis, and displacement.
The selected design will be analyzed further based on a theoretical
calculation of bone remodeling on the dental implant. The results
have shown that the design constructed passed the failure analysis.
Therefore, the selected design is proven to have a stable performance
at the recovery stage.
Abstract: Titanium and its alloys have been used extensively over the past 25 years as biomedical materials in orthopedic and dental applications because of their good mechanical properties, corrosion resistance, and biocompatibility. It is known that the surface properties of titanium implants can enhance the cellular response and play an important role in Osseo integration. The rate and quality of Osseo integration in titanium implants are related to their surface properties. The purpose of this investigation was to evaluate the effect of sandblasting and acid etching on surface morphology, roughness, the wettability of titanium. The surface properties will be characterized by scanning electron microscopy and contact angle and roughness measurements. The results show that surface morphology, roughness, and wettability were changed and enhanced by these treatments.
Abstract: Visual signal processing in human beings occurs in the occipital lobe of the brain. The signals that are generated in the brain are universal for all the human beings and they are called Visual Evoked Potential (VEP). Generally, the visually impaired people lose sight because of severe damage to only the eyes natural photo sensors, but the occipital lobe will still be functioning. In this paper, a technique of artificially generating VEP is proposed to enhance the visual ability of the subject. The system uses the electrical photoreceptors to capture image, process the image, to detect and recognize the subject or object. This voltage is further processed and can transmit wirelessly to a BIOMEMS implanted into occipital lobe of the patient’s brain. The proposed BIOMEMS consists of array of electrodes that generate the neuron potential which is similar to VEP of normal people. Thus, the neurons get the visual data from the BioMEMS which helps in generating partial vision or sight for the visually challenged patient.
Abstract: Present project consists in a study and a development
of piezoelectric devices for supplying power to new generation
pacemakers. They are miniaturized leadless implants without battery
placed directly in right ventricle. Amongst different acceptable
energy sources in cardiac environment, we choose the solution of a
device based on conversion of the energy produced by pressure
variation inside the heart into electrical energy. The proposed energy
harvesters can meet the power requirements of pacemakers, and can
be a good solution to solve the problem of regular surgical operation.
With further development, proposed device should provide enough
energy to allow pacemakers autonomy, and could be good candidate
for next pacemaker generation.
Abstract: In this paper, we present the results of a study of TiN thin films which are deposited by a Physical Vapour Deposition (PVD) and Ion Beam Assisted Deposition (IBAD). In the present investigation the subsequent ion implantation was provided with N5+ ions. The ion implantation was applied to enhance the mechanical properties of surface. The thin film deposition process exerts a number of effects such as crystallographic orientation, morphology, topography, densification of the films. A variety of analytic techniques were used for characterization, such as scratch test, calo test, Scanning electron microscopy (SEM), Atomic Force Microscope (AFM), X-ray diffraction (XRD) and Energy Dispersive X-ray analysis (EDAX).
Abstract: The first pn-type carrier-induced silicon Bragg-grating filter is demonstrated. The extinction-ratio modulations are 11.5 dB and 10 dB with reverse and forward biases, respectively. 8-Gpbs data rate is achieved with a reverse bias.
Abstract: Autologous Chondrocyte Implantation (ACI) is used worldwide since 1998 to treat cartilage defect. GEL based ACI is a new tissue-engineering technique to treat full thickness cartilage defect with fibrin and thrombin as scaffold for chondrocytes. Purpose of this study is to see safety and efficacy of gel based ACI for knee cartilage defect in multiple centres with different surgeons. Gel-based Autologous Chondrocyte Implantation (GACI) has shown effectiveness in treating isolated cartilage defect of knee joint. Long term results are still needed to be studied. This study was followed-up up to two years and showed benefit to patients. All enrolled patients with a mean age of 28.5 years had an average defect size of3 square centimeters, and were grade IV as per ICRS grading. All patients were followed up several times and at several intervals at 6th week, 8th week, 11th week, 17th week, 29th week, 57th week after surgery. The outcomes were measured based on the IKDC (subjective and objective) and MOCART scores.
Abstract: Myoelectric control system is the fundamental
component of modern prostheses, which uses the myoelectric signals
from an individual’s muscles to control the prosthesis movements.
The surface electromyogram signal (sEMG) being noninvasive has
been used as an input to prostheses controllers for many years.
Recent technological advances has led to the development of
implantable myoelectric sensors which enable the internal
myoelectric signal (MES) to be used as input to these prostheses
controllers. The intramuscular measurement can provide focal
recordings from deep muscles of the forearm and independent signals
relatively free of crosstalk thus allowing for more independent
control sites. However, little work has been done to compare the two
inputs. In this paper we have compared the classification accuracy of
six pattern recognition based myoelectric controllers which use
surface myoelectric signals recorded using untargeted (symmetric)
surface electrode arrays to the same controllers with multichannel
intramuscular myolectric signals from targeted intramuscular
electrodes as inputs. There was no significant enhancement in the
classification accuracy as a result of using the intramuscular EMG
measurement technique when compared to the results acquired using
the surface EMG measurement technique. Impressive classification
accuracy (99%) could be achieved by optimally selecting only five
channels of surface EMG.
Abstract: Objective: Safety and efficacy of Ahmed glaucoma
valve implantation for the management of uveitis induced glaucoma
evaluated on the five dogs with uncontrollable glaucoma. Materials
and Methods: Ahmed Glaucoma Valve (AGV®; New World
Medical, Rancho Cucamonga, CA, USA) is a flow restrictive, nonobstructive
self-regulating valve system. Preoperative ocular
evaluation included direct ophthalmoscopy and measurement of the
intraocular pressure (IOP). The implant was examined and primed
prior to implantation. The selected site of the valve implantation was
the superior quadrant between the superior and lateral rectus muscles.
A fornix-based incision was made through the conjunectiva and
Tenon’s capsule. A pocket is formed by blunt dissection of Tenon’s
capsule from the episclera. The body of the implant was inserted into
the pocket with the leading edge of the device around 8-10 mm from
the limbus. Results: No post-operative complications were detected
in the operated eyes except a persistent corneal edema occupied the
upper half of the cornea in one case. Hyphaema was very mild and
seen only in two cases which resolved quickly two days after surgery.
Endoscopical evaluation for the operated eyes revealed a normal
ocular fundus with clearly visible optic papilla, tapetum and retinal
blood vessels. No evidence of hemorrhage, infection, adhesions or
retinal abnormalities was detected. Conclusion: Ahmed glaucoma
valve is safe and effective implant for treatment of uveitic glaucoma
in dogs.
Abstract: Cochlear Implantation (CI) which became a routine
procedure for the last decades is an electronic device that provides a
sense of sound for patients who are severely and profoundly deaf.
The optimal success of this implantation depends on the electrode
technology and deep insertion techniques. However, this manual
insertion procedure may cause mechanical trauma which can lead to
severe destruction of the delicate intracochlear structure.
Accordingly, future improvement of the cochlear electrode implant
insertion needs reduction of the excessive force application during
the cochlear implantation which causes tissue damage and trauma.
This study is examined tool-tissue interaction of large prototype scale
digit embedded with distributive tactile sensor based upon cochlear
electrode and large prototype scale cochlea phantom for simulating
the human cochlear which could lead to small scale digit
requirements. The digit, distributive tactile sensors embedded with
silicon-substrate was inserted into the cochlea phantom to measure
any digit/phantom interaction and position of the digit in order to
minimize tissue and trauma damage during the electrode cochlear
insertion. The digit have provided tactile information from the digitphantom
insertion interaction such as contact status, tip penetration,
obstacles, relative shape and location, contact orientation and
multiple contacts. The tests demonstrated that even devices of such a
relative simple design with low cost have potential to improve
cochlear implant surgery and other lumen mapping applications by
providing tactile sensory feedback information and thus controlling
the insertion through sensing and control of the tip of the implant
during the insertion. In that approach, the surgeon could minimize the
tissue damage and potential damage to the delicate structures within
the cochlear caused by current manual electrode insertion of the
cochlear implantation. This approach also can be applied to other
minimally invasive surgery applications as well as diagnosis and path
navigation procedures.
Abstract: Excessive fretting wear at the taper-trunnion junction
(trunnionosis) apparently contributes to the high failure rates of hip
implants. Implant wear and corrosion lead to the release of metal
particulate debris and subsequent release of metal ions at the tapertrunnion
surface. This results in a type of metal poisoning referred to
as metallosis. The consequences of metal poisoning include;
osteolysis (bone loss), osteoarthritis (pain), aseptic loosening of the
prosthesis and revision surgery. Follow up after revision surgery,
metal debris particles are commonly found in numerous locations. Background: A stable connection between the femoral ball head
(taper) and stem (trunnion) is necessary to prevent relative motions
and corrosion at the taper junction. Hence, the importance of
component assembly cannot be over-emphasized. Therefore, the aim
of this study is to determine the influence of head-stem junction
assembly by press fitting and the subsequent
disengagement/disassembly on the connection strength between the
taper ball head and stem. Methods: CoCr femoral heads were assembled with High stainless
hydrogen steel stem (trunnion) by Push-in i.e. press fit; and
disengaged by pull-out test. The strength and stability of the two
connections were evaluated by measuring the head pull-out forces
according to ISO 7206-10 standards. Findings: The head-stem junction strength linearly increases with
assembly forces.
Abstract: Targeted drug delivery is a method of delivering
medication to a patient in a manner that increases the concentration
of the medication in some parts of the body relative to others.
Targeted drug delivery seeks to concentrate the medication in the
tissues of interest while reducing the relative concentration of the
medication in the remaining tissues. This improves efficacy of the
while reducing side effects. In the present work, we investigate the
effect of magnetic field, flow rate and particle concentration on the
capturing of magnetic particles transported in a stent implanted
fluidic channel. Iron oxide magnetic nanoparticles (Fe3O4)
nanoparticles were synthesized via co-precipitation method. The
synthesized Fe3O4 nanoparticles were added in the de-ionized (DI)
water to prepare the Fe3O4 magnetic particle suspended fluid. This
fluid is transported in a cylindrical tube of diameter 8 mm with help
of a peristaltic pump at different flow rate (25-40 ml/min). A
ferromagnetic coil of SS 430 has been implanted inside the
cylindrical tube to enhance the capturing of magnetic nanoparticles
under magnetic field. The capturing of magnetic nanoparticles was
observed at different magnetic magnetic field, flow rate and particle
concentration. It is observed that capture efficiency increases from
47-67% at magnetic field 2-5kG, respectively at particle
concentration 0.6mg/ml and at flow rate 30 ml/min. However, the
capture efficiency decreases from 65 to 44% by increasing the flow
rate from 25 to 40 ml/min, respectively. Furthermore, it is observed
that capture efficiency increases from 51 to 67% by increasing the
particle concentration from 0.3 to 0.6 mg/ml, respectively.
Abstract: Introduction: The process to build a better safety
culture, methods of error analysis, and preventive measures, starts
with an understanding of the effects when human factors engineering
refer to remote microscopic diagnosis in surgery and specially in
organ transplantation for the remote evaluation of the grafts. It has
been estimated that even in well-organized transplant systems an
average of 8% to 14% of the grafts (G) that arrive at the recipient
hospitals may be considered as diseased, injured, damaged or
improper for transplantation. Digital microscopy adds information on
a microscopic level about the grafts in Organ Transplant (OT), and
may lead to a change in their management. Such a method will
reduce the possibility that a diseased G, will arrive at the recipient
hospital for implantation. Aim: Ergonomics of Digital Microscopy
(DM) based on virtual slides, on Telemedicine Systems (TS) for
Tele-Pathological (TPE) evaluation of the grafts (G) in organ
transplantation (OT). Material and Methods: By experimental
simulation, the ergonomics of DM for microscopic TPE of Renal
Graft (RG), Liver Graft (LG) and Pancreatic Graft (PG) tissues is
analyzed. In fact, this corresponded to the ergonomics of digital
microscopy for TPE in OT by applying Virtual Slide (VS) system for
graft tissue image capture, for remote diagnoses of possible
microscopic inflammatory and/or neoplastic lesions. Experimentation
included: a. Development of an OTE-TS similar Experimental
Telemedicine System (Exp.-TS), b. Simulation of the integration of
TS with the VS based microscopic TPE of RG, LG and PG applying
DM. Simulation of the DM based TPE was performed by 2
specialists on a total of 238 human Renal Graft (RG), 172 Liver Graft
(LG) and 108 Pancreatic Graft (PG) tissues digital microscopic
images for inflammatory and neoplastic lesions on four electronic
spaces of the four used TS. Results: Statistical analysis of specialist‘s
answers about the ability to diagnose accurately the diseased RG, LG
and PG tissues on the electronic space among four TS (A,B,C,D)
showed that DM on TS for TPE in OT is elaborated perfectly on the
ES of a Desktop, followed by the ES of the applied Exp.-TS. Tablet
and Mobile-Phone ES seem significantly risky for the application of
DM in OT (p