35 research outputs found

    Thermo, Electrical and Structural Properties of Solid Electroyte Doped Bi2O3 Binary and Ternary Systems

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    In this study; production and characterization of Bi2O3 based solid electrolytes used in medium-temperature solid oxide fuel cells (IT-SOFC) were performed. Solid electrolyte samples were obtained using compounds Eu2O3, Dy2O3 and Bi2O3. Stable phase which can create the highest power density δ-Bi2O3 (cubic-fcc) was tried to be reached for IT-SOFC. X-ray diffractometry (XRD) and differential thermal analysis and thermal gravimeter (TG/DTA) with binary (Eu2O3-Bi2O3) and ternary (Eu2O3-Dy2O3-Bi2O3) powder materials were analyzed for crystal structure identification. Bi2O3-based compounds with the cubic structure have been identified in those composition regions ((Bi2O3)0,6(Eu2O3)0,3) and ((Bi2O3)1-x-y(Dy2O3)x(Eu2O3)y, 0.25 ≤ x ≤ 0.35, y=0,05). Four point measurement techniques were used for electrical characterization. The conductivity of the ternary system is higher than the conductivity of the binary system. The highest conductive sample is (Bi2O3)0,7(Dy2O3)0,25(Eu2O3)0,05 0.3 S/cm at 800 oC

    Decreased ocular pulse amplitude and retinal nerve fibre layer in multiple sclerosis

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    This study was conducted to assess ocular pulse amplitude and retinal nerve fibre layer in patients with multiple sclerosis and their correlation with disease duration and with severity. Retinal nerve fibre layer thickness was measured by Heidelberg Retinal Tomography II (HRT-II; Heidelberg Engineering, Dossenheim, Germany) and ocular pulse amplitude was measured by dynamic contour tonometry (Ziemer Ophthalmic Systems, Port, Switzerland) in 37 multiple sclerosis patients and 72 age- and gender-matched controls. Ocular pulse amplitude was significantly reduced and retinal nerve fibre layer was significantly thinner in temporal, superotemporal, and nasal sectors in patients with multiple sclerosis regardless of having an optic neuritis attack. The retinal nerve fibre layer was thinner in eyes with a previous optic neuritis attack compared with the eyes without an attack, but the difference was not significant. Ocular pulse amplitude showed a positive correlation with visual evoked potential amplitude and a negative correlation with visual evoked potential latency. Retinal nerve fibre layer thickness showed a significant negative correlation with the disease duration but not with visually evoked potential, disease severity, nor previous optic neuritis. These findings indicate that the process of degeneration starts in the early period of the disease, as our study group is composed of early-middle-stage multiple sclerosis patients, and is independent of relapses. © Informa Healthcare USA, Inc

    Oxidative stress of crystalline lens in rat menopausal model

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    Purpose: To evaluate lenticular oxidative stress in rat menopausal models. Methods: Forty Wistar female albino rats were included in this study. A total of thirty rats underwent oophorectomy to generate a menopausal model. Ten rats that did not undergo oophorectomy formed the control group (Group 1). From the rats that underwent oophorectomy, 10 formed the menopause control group (Group 2), 10 were administered a daily injection of methylprednisolone until the end of the study (Group 3), and the remaining 10 rats were administered intraperitoneal streptozocin to induce diabetes mellitus (Group 4). Total oxidant status (TOS), total antioxidant capacity (TAC), and oxidative stress index (OSI) measurements of the crystalline lenses were analyzed. Results: The mean OSI was the lowest in group 1 and highest in group 4. Nevertheless, the difference between the groups was not statistically significant in terms of OSI (p > 0.05). The mean TOS values were similar between the groups (p > 0.05), whereas the mean TAC of group 1 was significantly higher than that of the other groups (p < 0.001). Conclusions: Our results indicate that menopause may not promote cataract formation

    Pseudoxanthoma elasticum: A pediatric case

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    Pseudoxanthoma elasticum (PXE) is a multisystemic, metabolic and autosomal recessive inherited disorder affecting especially elastic fibers of skin, retina and blood vessels. The prevalence varies from 1:25,000 to 1:100,000. The average age of onset is 13.5 years. Yellowish papules 1-3 mm in diameter and plaques merging as linear or reticular pattern are mostly on antecubital fossae, popliteal fossae, inguinal region, lower clavicle, neck, axilla, flexural regions as umbilicus and trauma sites. Of the patients, 85% have eye involvement. The first symptom of eye involvement is spot retinal pigmentation. Cardiovascular complications occur usually in adults. The most common and early cardiovascular complication is intermittent claudication. There is no specific treatment for skin signs. Lifestyle changes may have important effects on prognosis. A male patient with 3-year history of yellowish papules on his neck and 1-year history of yellowish papules on his groins, was presented in this case report. This 7-year-old patient received a diagnosis of PXE based on medical story, clinical examination and histopathological findings. This case was presented as PXE is a rare disease and should be diagnosed by the clinician at early ages. © 2015 by Turkish Society of Dermatology

    Does Fundus Fluorescein Angiography Procedure Affect Ocular Pulse Amplitude?

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    Purpose. This study examines the effects of fundus fluorescein angiography (FFA) procedure on ocular pulse amplitude (OPA) and intraocular pressure (IOP). Materials and Methods. Sixty eyes of 30 nonproliferative diabetic retinopathy patients (15 males, 15 females) were included in this cross-sectional case series. IOP and OPA were measured with the Pascal dynamic contour tonometer before and after 5 minutes of intravenous fluorescein dye injection. Results. Pre-FFA mean OPA value was  mmHg and post-FFA mean OPA value was  mmHg (). Pre-FFA mean IOP value was  mmHg and post-FFA mean IOP value was  mmHg (). Conclusion. Although both mean OPA and IOP values were decreased after FFA procedure, the difference was not statistically significant. This clinical trial is registered with Australian New Zealand Clinical Trials Registry number ACTRN12613000433707

    Estimation of the Total Brain Volume Using Semi-Automatic Segmentation and Stereology of the Newborns' Brain MRI

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    Brain development begins in the early embryonic period and proceeds through the second decade of postnatal life. However information related to the development of the brain during this period is currently quite limited. The aim of the current study was to compare the total brain (cerebrum, cerebellum and brain stem, without the ventricular system) volumes in newborns using stereological (point-counting) and semi-automatic segmentation methods and Archimedes' principle. Seven newborn cadavers, aged 39.9 (+/- 1.2) weeks, were included in the present study. Firstly, the total brain (TB) volume was determined by the use of the fluid displacement technique and then magnetic resonance images were analyzed by using two methods. The mean (+/- SD) TB volumes by fluid displacement, Cavalieri principle (point-counting), and semi-automated segmentation methods were 288.70 +/- 76.18, 270.12 +/- 78.93 and 282.39 +/- 73.17 cm(3) respectively. We did not find any significant differences among the three methods (p>0.05). From these results, it can be concluded that the semi-automated segmentation method and stereological technique can be used for reliable volume estimation of total brains in neonates. Based on these techniques we compared here in, the clinician may evaluate the growth of the brain in a more efficient and precise manner

    Early diagnosis of pancreatic cancer by machine learning methods using urine biomarker combinations

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    The most common type of pancreatic cancer is pancreatic ductal adenocarcinoma (PDAC), which accounts for the vast majority of pancreatic cancers. The five-year survival rate for PDAC due to late diagnosis is 9%. Early diagnosed PDAC patients survive longer than patients diagnosed at a more advanced stage. Biomarkers can play an essential role in the early detection of PDAC to assist the health professional. Machine learning and deep learning methods are used with biomarkers obtained in recent studies for diagnostic purposes. In order to increase the survival rates of PDAC patients, early diagnosis of the disease with a noninvasive test is a critical need. Our study offers a promising approach for the early detection of PDAC with noninvasive urinary biomarkers and carbohydrate antigen 19-9 (CA19-9). The Kaggle Urinary Biomarkers for Pancreatic Cancer (2020) open-access dataset consisting of 590 participants was used in this study. Seven machine learning classifiers (support vector machine (SVM), naive Bayes (NB), k-nearest neighbors (kNN), random forest (RF), light gradient boosting machine (LightGBM), AdaBoost, and gradient boosting classifier (GBC)) to detect PDAC disease classifier were used. Binary and multiple classification processes were carried out. Data was validated in our study using 5-10-fold crossvalidation. This study aimed to determine the best machine learning model by analyzing the performance of machine learning models in determining the classes of healthy controls, pancreatic disorders, and patients with PDAC. It is a remarkable finding that ensemble learning models were more successful in all our groups. The most successful classification method in classifying healthy controls and patients with PDAC was CV-10, while the GBC (92.99%) model was (AUC = 0.9761). The most successful classification method in classifying patients with pancreatic disorders and PDAC was CV-10, while the LightGBM (86.37%) model was (AUC = 0.9348). In the classification of healthy controls, pancreatic disorders, and patients with PDAC, the most successful classification method was CV-5, while the GBC (72.91%) model was (AUC = 0.8733)
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