Browsing by Author "Yuksekkaya, Mehmet"

Now showing 1 - 4 of 4

Desing and Test of an Incubator Analyzer
(2018) Sen, Gamze Tilbe; Yuksekkaya, Mehmet; 0000-0002-2665-5799; P-1760-2016
Incubators are cabins that provide the environment with necessary conditions for premature or newborn babies, and they are designed to allow monitoring and care of the baby. The incubator analyzer is the analyzer that shows the performance of the incubator. Knowing how close the values of a medical device are to the actual values is very important in the treatment process. To ensure the accuracy of medical devices, tests and controls are required. As a result of periodic tests and controls, it is possible to reduce the risks by preventing incorrect measurements. If the temperature, humidity and oxygen sensors of the incubators are measured incorrectly, the baby's life would be threatened. This study aims to determine the design requirements of a single incubator analyzer that measures heat, oxygen and humidity in the incubator and to design an analyzer. The general design of the incubator analyzer consists of a battery circuit, a microcontroller, a liquid crystal display (LCD) screen, five temperature sensors, a humidity sensor and an oxygen sensor. Incubator standards of our country and EU has been reviewed according to the design. In addition, within the scope of the project, the sensors in accordance with the standards have been researched and determined, but due to their high cost, alternative sensors are preferred. By that the design of the analyzer can be a model for the actual device. Proper firmware is programmed for temperature, oxygen and humidity sensors, and data from those sensors are processed and displayed on a LCD screen. Also a suitable case is designed by computer aided programs. The analyzer is tested in incubators and functioned properly. With this project, it is determined that a cost effective incubator analyzer can be designed and with more sensitive sensors proper standards can be achieved. This project can be a model for incubator analyzer design.
Engineering long shelf life multilayer biologically active surfaces on microfluidic devices for point of care applications
(2016) Asghar, Waseem; Yuksekkaya, Mehmet; Shafiee, Hadi; Zhang, Michael; Ozen, Mehmet O.; Inci, Fatih; Kocakulak, Mustafa; Demirci, Utkan; 26883474
Although materials and engineered surfaces are broadly utilized in creating assays and devices with wide applications in diagnostics, preservation of these immuno-functionalized surfaces on microfluidic devices remains a significant challenge to create reliable repeatable assays that would facilitate patient care in resource-constrained settings at the point-of-care (POC), where reliable electricity and refrigeration are lacking. To address this challenge, we present an innovative approach to stabilize surfaces on-chip with multiple layers of immunochemistry. The functionality of microfluidic devices using the presented method is evaluated at room temperature for up to 6-month shelf life. We integrated the preserved microfluidic devices with a lensless complementary metal oxide semiconductor (CMOS) imaging platform to count CD4(+) T cells from a drop of unprocessed whole blood targeting applications at the POC such as HIV management and monitoring. The developed immunochemistry stabilization method can potentially be applied broadly to other diagnostic immunoassays such as viral load measurements, chemotherapy monitoring, and biomarker detection for cancer patients at the POC.
Quantitative Color Doppler Ultrasonography Measurement of Thyroid Blood Flow in Patients with Graves' Disease
(2020) Yuksekkaya, Ruken; Celikay, Fatih; Gul, Serdar S.; Yuksekkaya, Mehmet; Kutluturk, Faruk; Ozmen, Cansel; 0000-0002-2665-5799; 32107993; P-1760-2016
Background: Graves' Disease is an autoimmune disorder characterized by increased levels of thyroid hormones correlated with increased thyroid blood flow. Thyroid scintigraphy is an important and conventional method. However, it has limited accessibility, has ionizing radiation, and is expensive. Objectives: To investigate the thyroid blood flow in patients with Graves' Disease by color Doppler Ultrasonography and a newly developed software Color Quantification. Methods: Forty-one consecutive subjects with GD and 41 healthy controls were enrolled. Color Doppler ultrasonography parameters of the thyroid arteries and Color Quantification values of the gland were measured by a radiologist. The correlations between thyroid blood flow parameters, levels of (99m)Technetium pertechnetate uptake, thyrotropin, and free thyroxine were evaluated. The diagnostic performances of these parameters were investigated. Results: The peak systolic-end diastolic velocities of thyroid arteries and Color Quantification values were increased in the study group (p < 0.05 for all). We observed negative correlations between thyrotropin levels and peak-systolic and end-diastolic velocities of superior thyroid arteries and Color Quantification values. There were positive correlations between (99m)Technetium uptake levels and thyroid blood flow parameters (p < 0.05 for all). In the diagnostic performance of thyroid blood flow parameters, we observed utilities significantly in peak-systolic and end-diastolic velocities of thyroid arteries and Color Quantification values (p < 0.05 for all). Conclusion: The increased peak-systolic and end-diastolic velocities of thyroid arteries, and increased Color Quantification values might be helpful in the diagnosis of Graves' Disease.
Reduced Graphene Oxide-GelMA Hybrid Hydrogels as Scaffolds for Cardiac Tissue Engineering
(2016) Shin, Su Ryon; Zihlmann, Claudio; Akbari, Mohsen; Assawes, Pribpandao; Cheung, Louis; Zhang, Kaizhen; Manoharan, Vijayan; Zhang, Yu Shrike; Yuksekkaya, Mehmet; Wan, Kai-tak; Nikkhah, Mehdi; Dokmeci, Mehmet R.; Tang, Xiaowu (Shirley); Khademhosseini, Ali; 0000-0002-2665-5799; 27254107; P-1760-2016
Biomaterials currently used in cardiac tissue engineering have certain limitations, such as lack of electrical conductivity and appropriate mechanical properties, which are two parameters playing a key role in regulating cardiac cell behavior. Here, the myocardial tissue constructs are engineered based on reduced graphene oxide (rGO)-incorporated gelatin methacryloyl (GelMA) hybrid hydrogels. The incorporation of rGO into the GelMA matrix significantly enhances the electrical conductivity and mechanical properties of the material. Moreover, cells cultured on composite rGO-GelMA scaffolds exhibit better biological activities such as cell viability, proliferation, and maturation compared to ones cultured on GelMA hydrogels. Cardiomyocytes show stronger contractility and faster spontaneous beating rate on rGO-GelMA hydrogel sheets compared to those on pristine GelMA hydrogels, as well as GO-GelMA hydrogel sheets with similar mechanical property and particle concentration. Our strategy of integrating rGO within a biocompatible hydrogel is expected to be broadly applicable for future biomaterial designs to improve tissue engineering outcomes. The engineered cardiac tissue constructs using rGO incorporated hybrid hydrogels can potentially provide high-fidelity tissue models for drug studies and the investigations of cardiac tissue development and/or disease processes in vitro.