MF - Makale Koleksiyonu | Biyomedikal Mühendisliği Bölümü / Department of Biomedical Engineering
https://hdl.handle.net/11729/1147
Biyomedikal Mühendisliği Bölümüne ait makale koleksiyonunu içerir.2024-03-29T00:36:20ZDeveloping an efficient deep neural network for automatic detection of COVID-19 using chest X-ray images
https://hdl.handle.net/11729/3096
Developing an efficient deep neural network for automatic detection of COVID-19 using chest X-ray images
Sheykhivand, Sobhan; Mousavi, Zohreh; Mojtahedi, Sina; Yousefi Rezaii, Tohid; Farzamnia, Ali; Meshgini, Saeed; Saad, Ismail
The novel coronavirus (COVID-19) could be described as the greatest human challenge of the 21st century. The development and transmission of the disease have increased mortality in all countries. Therefore, a rapid diagnosis of COVID-19 is necessary to treat and control the disease. In this paper, a new method for the automatic identification of pneumonia (including COVID-19) is presented using a proposed deep neural network. In the proposed method, the chest X-ray images are used to separate 2–4 classes in 7 different and functional scenarios according to healthy, viral, bacterial, and COVID-19 classes. In the proposed architecture, Generative Adversarial Networks (GANs) are used together with a fusion of the deep transfer learning and LSTM networks, without involving feature extraction/selection for classification of pneumonia. We have achieved more than 90% accuracy for all scenarios except one and also achieved 99% accuracy for separating COVID-19 from healthy group. We also compared our deep proposed network with other deep transfer learning networks (including Inception-ResNet V2, Inception V4, VGG16 and MobileNet) that have been recently widely used in pneumonia detection studies. The results based on the proposed network were very promising in terms of accuracy, precision, sensitivity, and specificity compared to the other deep transfer learning approaches. Depending on the high performance of the proposed method, it can be used during the treatment of patients.
2021-06-01T00:00:00ZComputational model of the ventricular action potential in adult spontaneously hypertensive rats
https://hdl.handle.net/11729/2053
Computational model of the ventricular action potential in adult spontaneously hypertensive rats
Padmala, Srikanth; Demir, Sıddıka Semahat
Introduction: Cardiac hypertrophy has substantial clinical significance because many hypertrophic cells have markedly prolonged repolarization behavior, which may lead to increased risk for cardiac arrhythmias. Spontaneously hypertensive rat (SHR) is one model of hypertension that is studied extensively and is considered to be the best laboratory model of human hypertension. We extended our previously published model of the rat ventricular myocyte to simulate the effects of hypertrophy in SHR. Methods and Results: In SHR it has been shown that the membrane capacitance is increased, the density of transient outward K+ current is decreased, the sarcoplasmic reticulum Ca 2+ ATPase activity is reduced, and the cell volumes are increased compared to those of the normal rat. We introduced these changes into our previous model of the rat ventricular myocyte and simulated the ventricular action potential of SHR. Our results demonstrated increased action potential duration (APD) and increased peak systolic value of the intracellular calcium transient in SHR. Simulations with reduced extracellular K+ concentration ([K+]o) have shown that there is increased APD shortening in SHR compared to that of the normal rat. Conclusions: Our computational model qualitatively simulated the electrophysiologic changes observed in SHR and provided the plausible mechanistic linkage between the prolonged APD and increased inotropy. Our model results also demonstrated the electrophysiologic changes observed with reduced [K+]o in SHR, a finding that is clinically significant in hypertensive patients with left ventricular hypertrophy undergoing diuretic treatment.
PubMed ID: 12950545
2003-09-01T00:00:00ZHastane enfeksiyonlarına karşı implant yüzeylerinden kontrollü ilaç salımı
https://hdl.handle.net/11729/2127
Hastane enfeksiyonlarına karşı implant yüzeylerinden kontrollü ilaç salımı
Önder, Sakip
Hastane enfeksiyonları vücuda yerleştirilen implant malzemelerinin başarısını etkileyen en önemli faktörlerden birisidir. Enfeksiyonlar sonucu hastalar ciddi ağrılara maruz kalabilir, doku ve implant malzemesi arasındaki bağlanma zayıflayabilir, revizyon cerrahisi gerekebilir, hastadan implantın geri alınması söz konusu olabilir. Bu çalışmada enfeksiyonlarının önlenmesinde kullanılabilecek bir polimer/metal (kitosan/titanyum) sistemi üzerinde kontrollü antibiyotik (gentamisin) salım çalışmaları yapılmıştır. İlk olarak antibiyotik yüklü polimerler titanyum yüzeylere tutuklanmış, sonrasında farklı kuruma koşullarına (hava ile kurutma-liyofilizasyon) maruz bırakılmıştır. Liyofilizasyon işlemi uygulanan yüzeylerde porlu yapılar elde edilmiştir. Porlu yapının hem yüzeylerden salımı yapılan antibiyotik miktarı üzerine hem de kemik hücrelerinin yüzeylere tutunması ve çoğalması üzerine olan etkileri incelenmiştir. Sonuç olarak liyofilizasyon işlemi sonrasında oluşan porlu yapıların yüzeylerden antibiyotik salımını arttırdığı görülmüştür. Hücre çoğalması testi (MTS) ise özellikle 5. günde porlu kitosan ile kaplı titanyum yüzeylerinde kemik hücrelerinin düz kitosan kaplı yüzeylere kıyasla çok daha fazla çoğaldığını göstermiştir.; Hospital infections are one of the most important factors that affect the success of implant materials. Patients may have strong pain, integration between newly formed tissue and implant material may weaken, revision surgery may be needed, and even implant may be taken back from the patient as a result of infections. In this study, a polymer/metal (chitosan/titanium) system that can be used to prevent infections was tested in controlled antibiotic
(gentamicin) release studies. Firstly, antibiotic loaded polymers were immobilized onto titanium substrates and then these samples were exposed to different drying conditions (air drying-freeze drying). Porous structures were formed on the titanium samples after freeze-drying. The effects of porous structure on the amount of released antibiotic from surfaces and osteoblast attachment & proliferation were investigated. As a result, it was shown that porous structures leaded to an increase in released antibiotic amount. Furthermore, cell proliferation test (MTS) showed that cell proliferation was higher on porous chitosan coated surfaces than smooth chitosan coated surfaces, especially at day 5.
2016-01-01T00:00:00ZEffect of magnesium and osteoblast cell presence on hydroxyapatite formation on (Ti,Mg)N thin film coatings
https://hdl.handle.net/11729/1160
Effect of magnesium and osteoblast cell presence on hydroxyapatite formation on (Ti,Mg)N thin film coatings
Önder, Sakip; Çalıkoğlu Koyuncu, Ayşe Ceren Eren; Köse, Gamze Torun; Kazmanlı, Kürşat Muhammet; Kök, Fatma Neşe; Ürgen, Mustafa
TiN and (Ti,Mg)N thin film coatings were deposited on Ti substrates by an arc-physical vapor deposition technique. The effect of cell presence on hydroxyapatite (HA) formation was investigated using surfaces with four different Mg contents (0, 8.1, 11.31, and 28.49 at.%). Accelerated corrosion above 10 at.% Mg had a negative effect on the performance in terms of both cell proliferation and mineralization. In the absence of cells, Mg-free TiN coatings and low-Mg (8.1 at.%)-doped (Ti,Mg)N surfaces led to an early HA deposition (after 7 days and 14 days, respectively) in cell culture medium (DMEM), but the crystallinity was low. More crystalline HA structures were obtained in the presence of the cells. HA deposits with an ideal Ca/P ratio were obtained at least a week earlier, at day 14, in TiN and low-Mg (8.1 at.%)-doped (Ti,Mg)N compared with that of high-Mg-containing surfaces (>10 at.%). A thicker mineralized matrix was formed on low-Mg (8.1 at.%)-doped (Ti,Mg)N relative to that of the TiN sample. Low-Mg doping (<10 at.%) into TiN coatings resulted in better cell proliferation and thicker mineralized matrix formation, so it could be a promising alternative for hard tissue applications.
2016-07-19T00:00:00Z