In this study, tendons that holds skeletal and muscular system together are investigated with the help of hyperelastic material models and results of different material models are interpreted with the help of computer aided engineering programs. Axial forces are applied to bovine tendons in order to obtain stress-strain curve while doing constitutive modelling. After that, curve fitting methods are used to get the Mooney-Rivlin and Ogden constants. Constitutive model is formed by finite element model with the help of computer aided engineering programs and results of Mooney-Rivlin and Ogden models are examined.
Cardiovascular diseases represent the leading causes of worldwide morbidity and mortality. These diseses causes death of more than 20 million people annually. More than 600,000 cardiovascular surgical interventions are performed every year and this costs around 200 billion dollars. The most prevalent cardiovascular diseases are heart tissue diseases which cause heart attack. One of the most prominent solution for this problem is to develop heart valves and heart tissues that are fabricated by 3D organ biofabrication methodologies such as bioprinters. The purpose of this research is; to fabricate heart valves and endothelial myocard tissues that have high durability and high biocompatibility by the help of stereolithography which is the most trending technique among other 3D bioprinting techniques.
In this study, the impedance spectroscopy is used as a detection tool in order to characterize graphene oxide and reduced graphene oxide coating on the gold surfaces. Gold surfaces are chosen as commercial surface electrodes. The impedance of redox solution through bare gold electrodes, graphene oxide and reduced graphene oxide coated gold electrodes is measured.
In recent years, breast cancers have been diagnosed by various imaging modalities. One of those imaging methods is Diffuse Optical Tomography (DOT). Currently, in imaging systems, image processing methods which is the next stage when digital images are obtained, are important task for the images to be well formed. This study was applied interpolation methods, one of the image processing methods to make the images better, to protect the details and also enlargement and resizing without distortion. In this study, we used three-dimensional (3D) images generated by measurements from breast phantom with the DOT system. Four interpolation methods; nearest neighbor interpolation, bilinear interpolation, bicubic interpolation and cubic spline interpolation are applied to the 3D images. The signal-to-noise ratios (SNR) were calculated to determine the quality of the images after the interpolation methods applied. In order to evaluate the images obtained from different directions and angles, two dimensional (2D) and three dimensional (3D)images were created and their advantages and disadvantages were compared. After interpolation methods were applied, signal-to-noise ratios (SNR) were compared and tested for compatibility with our system and it was determined that the most appropriate method was the cubic spline interpolation.
The heart rate measured by the user via the Grove pulse sensor is transferred to the Arduino Uno via the IIC communication protocol channel. The data received by Arduino Uno is accompanied by time-date information from the RTC DS1307 module. The processed data is then recorded to the SDCard on the Ethernet Shield at intervals of 4 seconds using the SPI communication protocol. The recorded data is also sent via serial communication via the HC-06 Bluetooth module and displayed by the "Arduino Bluetooth Controller" application in the smartphone.
Diabetes is a condition where the body does not produce enough insulin to convert sugar to energy, leading to a build up of sugar in the blood. This leads to a number of problems, including diabetic retinopathy. Diabetic retinopathy is a complication of diabetes that causes damage to the blood vessels of the retina that allowing you to see fine detail. It causes progressive damage to the retina. This paper proposes a simple yet an efficient approach for automatic detection of the exudates of the Diabetic Retinopathy. The detection of exudates of diabetic retinopathy is composed of eight steps: 1. RGB to gray conversion. 2. Moving mean to 0.5 3. Max Filter 4. Threshold specification 5. Optic disk removal 6. Remove of objects which is not exudates 7. Thresholding original image using the specified exudate regions 8. Computing statistical measures.
This study aims to specify biomarkers of Parkinson's disease mild cognitive impairment (PD-MCI) based on fractional anisotropy (FA) and mean diffusivity (MD) maps obtained from diffusion weighted magnetic resonance imaging (DWMRI). T1 and diffusion weighted MR images collected from 27 cognitively normal Parkinson's disease (PD-CN), 32 mild cognitively impaired Parkinson's disease (PD-MCI), and 18 healthy control (HC) volunteers, at a clinical 3T MR scanner, were processed using FMRIB Software Library (FSL)'s toolboxes. Average regional values of FA and MD maps and tract based spatial statistics (TBSS) were utilized to define statistically significant differences between the participant subject groups.
In this paper, the effects of spatial relationships in the classification of labeled cells in histopathological images have been evaluated. Firstly, the features of the square windowing cells in different sizes related to Haralick, Tamura and color spaces have been extracted and have been merged. After that, the training and test data sets have been created by using 10 fold cross-validation. Then, data sets have been classified by k-nearest neighbors, random forest and support vector machine algorithms. The accuracies of different window sizes on these classifiers have been observed. As a conclusion, a method for optimal window size has been recommended and comparative results have been presented in the graphics and in the tables.
In this study, new fundamentals charecteristics and circuit model of the three dimensional electrically coupled cell networks are introduced in fractional domain. First, the general expression in matrise forms for the typical equivalent impedance and transfer function of the circuit network are derived by using node voltage analysis method in fractional domain equivalent impedance and transfer function are calculated in matrice form with the implicit analytical expression. Then, the effects of five system parameters (inductance(L), capasitance(C), the number of cell units(n) and fractional orders (α,β)) on the empedance and electrical network characteristics are investigated by the numerical computer simulations. Finally, PSPICE simulations which Show the experimental performance are applied to validate the study and simulation results are presented.
The proposed work covers an ionic electroactive polymer actuator production for use in a prosthetic finger design. The best mechanical design will be possible if it considers anatomical features of the real finger/hand structure. A number of different finger movements for different purposes are formed by the antagonistic pairs of muscles. Ionic electroactive polymer actuators are intended to be used instead of intrinsic muscles, which enable precise movement of the hand beyond the force required for movement due to their low power consumption, low noise, high power/mass ratio.
In pharmacological experiments, the effect of ion concentrations on Action potential (AP) and its association with important neurological disorders such as stroke, epilepsy and depression has been investigated. In this paper, Hodgkin-Huxley (HH) and Morris-Lecar (ML) membrane models, which have contributed to the literature of theoretical neural science, have been studied. In the first step, these two models have been simulated individually in Simulink environment using Matlab software. In the second step, the ratio of the amount of extracellular ion to the amount of intracellular ion was expressed as H d /H i . Based on Na + and K + as ions, the effect of H d /H i ratio change on AP signal was investigated based on HH and ML as a model. In the HH model, it was searched that the H d /H i change due to sodium ions influenced the amplitude of AP and the depolarization phase. The change in H d /H i ratio due to potassium ion concentrations was found to affect the threshold and hyper-polarization phase of AP. In the ML membrane model, it was observed that the change in H d /H i ratio due to intracellular and extracellular Ca +2 and K + ion concentrations affected the formation time of AP, firing time, amplitude and formation phases. HH and ML models showed similarity in the same parameters.
In cancer treatments photodynamic therapy, because of being a minimally invasive method and having no significant harmful side effect to the patient. This method begins with the administration of photosensitizer material prior to treatment in the tissue, which reacts chemically to the specific wavelength light. Dosimeter calculations determine the time required for photosensitizer the body to remain only in the tumor. At the end of this period, the tumor tissue becomes eligible for targeted treatment. In order to be able to create the thermal effect on the tissue with the laser beam, a laser with a constant wavelength must be used. When photosensitizer provides sufficient energy in the target tissue exited with specific wavelength light energy in the cell, the cancer cells lead to necrosis. In order to complete the treatment successfully, Photodynamic therapy system's laser diode must have a constant temperature and constant output power so that it can generate constant wavelengths. Since the laser diode temperature is directly related to the wavelength and the output power, control of the temperature at a single point is an essential issue.. In the study, the selected laser diode need to be stabilized at a temperature of 15 °C so that it could operate steadily at a wavelength of 635 nm which can excite the ALA- 5. The thermoelectric controller (TEC), the thermistor directly connected to the laser diode, detects the temperature of the diode. The sensed temperature value is applied to the (Dspic30f4013) microcontroller's ADC circuit via an analog circuit that will produce 5V for the maximum value and 0V for the minimum value of the thermistor. This feedback from the thermistor with PID control on the microprocessor determines the PWM on and off time ratio. Cooling control is provided instantaneously by PWM signal applied on the thermoelectric material.
Currently, there are several devices have been used for diagnosis of breast cancer such as X-ray tomography ultrasound and MRI. These devices sending harmful photons to the body, costly, lack of resolution and portability. Therefore searching new methods to diagnose breast cancer are necessity. One of these methods is Diffuse Optical Tomography (DOT). In DOT study, 808 nm wavelength laser which has a high penetration to tissue is used. In in-vitro experiments, DOT measurements were acquired from a breast phantom was mixture of water and 1% Intralipid. Indocyanine green (ICG) was added to the mixture to make absorption coefficient 0.04 cm -1 , similar to the breast tissue. A transparent balloon was filled Intralipid and ICG with absorption coefficient of 0.16 cm -1 to mimic tumor inclusion 3D Image of breast phantoms were created by using Algebraic Reconstruction Technique (ART) and Truncated Conjugate Gradient (TCG) methods. The results obtained by the TCG algorithm are closer to the real, which is the closest of inclusion's dimensions and contains less artifact. The system which we use consists of 2401 measurement and 2250 voxels so it is called as over-determined systems. According to findings, we inference that TCG algorithm works better than ART for over-determined system.
In this study, it was aimed to perform cell detection in histopathologic images which contains ground truth information. Firstly, in the patches which taken from the image, it is aimed to find out whether there is a certain frequency content in certain directions by using Gabor Filter. Features are extracted from the patches. Thus, training and test data sets were created. Then, using the training data sets, k-nearest neighbors, support vector machine, and random forest trained classification methods were used for classification. The success of classifications were observed with using test dataset and the results were presented.
In undevelped countries waterborn epidemics are significantly threatening for health. Cholera is one of the main such diseases. For the initiation of preventive health care services, studies for designing biosensors that detects the cholera toxin which is the cause of this disease is necessary. Besides the experiments performed during the design which uses SPR and SPFS technology, usage of computational biology takes an important place. Investigation of the binding mechanisms taking place in the biosensor is possible at the atomistic scales by molecular modelling techniques and this going to be a preliminary work for the similar biosensor designs. In this research, ligands enable the detection by ensuring the specific binding of cholera toxin B (Ch B) were determined by the computation of binding energies and binding positions and interactions were investigated.
Magnetic Particle Imaging (MPI) is a new imaging modality that is used for imaging the spatial distribution of superparamagnetic iron oxide nanoparticles injected as tracers. Image reconstruction in MPI can be realized directly in X-space or with a system calibration matrix. It is envisaged that obtaining a system calibration matrix would take days for a field of view of clinical purposes. On the other hand, the need for real-time imaging for applications such as interventional angiography implies that faster and more efficient reconstruction algorithms are needed than the ones at present. In this work, we present rapid system calibration with compressive sensing, and reconstruction results that have higher resolution and contrast with respect to the most common technique, Kaczmarz, using Alternating Direction Method of Multipliers (ADMM).
In droplet based microfluidics, ability of controlling the motion of the droplets insidechips have great importance for the applications such guiding, sorting, mixing and dividing of liquid droplets. In this study, we fabricated hydrophilic microchannels inside the chips by femtosecond laser ablation technique in order to control droplet motion. The laser beam focused on PDMS converts the irradiated regions to hydrophilic by ablating the coating entirely from the surface. Droplets follow the tracks because of the difference in wettability of ablated region and PDMS surfaces together with the topographical profile of the ablated tracks. Within this study, we investigated the manipulation of three kind of liquid droplets (water/surfactant mixture, pure water and pure etylene glycol) along microchannels with depths of 1μm, 1.5μm and 2μm. We verified the experimental results with simulations and analyzed the trajectories of the moving droplets with the different wettability along the tracks of different depths. Our results showed that, while topographical effects play role in droplet guiding for 1.5μm and 2μm tracks, for the case of 1μm depth of channel, surface energy modifications cause the guiding rather than the topographical step on the surface. These results will pioneer for sorting applications of different micro droplets mixed in the same microfluidic chip.
Transcranial Magnetic Stimulation is a noninvasive magnetic stimulation of the motor cortex and motor pathways. Responses obtained from the target muscles through TMS can be evaluated electrophysiologically. There are 20 healthy volunteers who use the right hand actively in the study. There are active right hand 20 healthy volunteers in the study. Two sEMG electrodes are placed in the Abductor Pollicis Brevis (APB) and Orbicularis Oris (O.oris) muscles. APB muscle constitutes a hand representative in the cortical motor mapping. O.Oris muscle constitutes a face representative in the cortical motor mapping. The position, amplitude and latency values of muscular action potentialsinduced by magnetic stimulation are determined by signal processing methods. The results are mapped on 3-D human model. When the right-hand representation map is examined, the hot spot of the APB muscle is found as the C1. While the motor potential of the hot spot is 6.89(±1.67) mV, the latency time is 20.98(±0.87) ms. When the right-face representation map is examined, the hot spot of the O.Oris muscle's found as the F5. While the motor potential of the hot spot is 2.83(±1.81) mV, the latency time is 4.95(±0.05) ms. Moreover, the face representation intersects with the hand representation at some points and is active at distances close to the hand representation.
The modeling of the dynamic behavior of the human arm is an important issue in robotics, biomedical and medical fields. In this study, it was aimed to construct an inverse dynamics model for the sequential motion of the arm subjected to external force fluctuations using a two degree of freedom manipulator. In experiments with healthy participants, EMG signals measured from the arm surface during the arm's stationary position task and the planar motion task, and displacements in the x- and yplane of the arm were recorded. In previous studies, the arm admittance was estimated numerically and experimentally for both tasks. To demonstrate the dynamic arm dynamics, the model parameters obtained with the inverse model will be compared with the parameters calculated experimentally and with matrix frequency response method's.
The following topics are dealt with: medical image processing; biomechanics; diseases; cellular biophysics; neurophysiology; medical signal processing; cancer; brain; biomedical MRI; prosthetics.
